MATERIAIS E PROCESSOS INOVADORES - ubi.pt Actas 2010.pdf · MATERIAIS E PROCESSOS INOVADORES ......

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S I M P Ó S I O 2 0 10

MATERIAIS E PROCESSOS INOVADORES

COVILHÃ, UNIVERSIDADE DA BEIRA INTERIOR2-3 DE DEZEMBRO DE 201O

LIVRO DE ACTAS

Unidade de Materiais Têxteis e Papeleiros

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Reservados todos os direitos

Título:Actas do Simpósio 2010: Materiais e Processos Inovadores

UMTP, Universidade da Beira Interior

2-3 de Dezembro de 2010, Covilhã - Portugal

Coordenador da Edição:Manuel José dos Santos Silva

Comissão Organizadora:Manuel José dos Santos Silva

Ana Maria Carreira Lopes

José Mendes Lucas

Rogério Simões

Ana Paula Costa

Isabel Cristina Gouveia

Maria de Lurdes Franco Ciríaco

Carla Sofia Gaiolas

Isabel G. Trindade

Susana Ramos

Comissão Científica:Manuel José dos Santos Silva

Ana Maria Carreira Lopes

José Mendes Lucas

Rogério Simões

Maria Isabel Ferra

Isabel Cristina Gouveia

Isolina Gonçalves

Jesus Rodilla

Maria Emilia Amaral

Rui Miguel

Apoio Técnico:Maria da Conceição Camisão

Execução Gráfica:Serviços Gráficos da Universidade da Beira Interior

Tiragem:550 exemplares

ISBN:978-989-654-074-6

Depósito Legal:330730/11

Apoios:

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ÍNDICE

Programa da Conferência / Conference Programme ........................................................................ 9

Textiles and Paper - Innovative Materials and Processes, M. J. Santos Silva ....................... 15

The Paper group in the Unit of Textile and Paper materials, Rogério M. S. Simões .......... 19

The Textile Science Working Group in MTP Unit: Present and Future Research, José M.Lucas .................................................................................................................................................... 21

The Fundamental Sciences Group in the Unit of Textile and Paper Materials, A. Lopes ...... 24

Laminar Newtonian flows in square curved ducts at moderate Reynolds number, J. Malheiro,P. J. Oliveira, F. T. Pinho .............................................................................................................. 27

Influence of the technology of simple and double wool fabrics in the design and performance ofgarments, R. Miguel, S. Melo, M. Pereira, J. Lucas, M. Santos Silva ................................ 31

Influence of surface sizing with different binder systems on inkjet print quality, S. Sousa, A. P.M. de Sousa, B. M. Reis, A. Ramos ............................................................................................ 35

Filmes de nanocompósitos: sua utilização na Fotoelectrodegradação do Corante AO7, T. Frade,A. Videira, A. Gomes, M. I. da Silva Pereira, O. Monteiro, L. Círiaco, A. Lopes ......... 39

Antioxidant activity and bioactive compounds of methanolic extracts of some Portuguese shrubsspecies, Â. Luís, F. Domingues, A. P. Duarte ............................................................................. 43

Anodic oxidation of the dye Acid Orange 7 at different anode materials, D. Santos, L. Ciríaco,M.J. Pacheco, A. Lopes ................................................................................................................... 47

Intelligent Clothing for Health Care, I. G. Trindade, M. Pereira, R. Salvado, J. Lucas, N. Garcia,J. Santos Silva, R. Miguel ............................................................................................................... 50

Hydrolysis of 3-alkyl-2-methylbenzoazol-3-ium iodides: an useful reaction, S. S. Ramos, L. V. Reis,P. F. Santos, P. Almeida ................................................................................................................... 54

Non-Newtonian Flows in Two dimensional T-junctions, H. M. Matos, P. J. Oliveira ............ 56

Comparative study of fibres for Eucalyptus globulus based paper using experimental characterizationand 3D paper modeling, Curto, J., Conceição, E., Portugal, A., Simões, R. ........................ 60

Electrocoagulation of leachates from sanitary landfills, P. Rodrigues, D. Norma, M. J. Pacheco,L. Ciríaco, A. Lopes ......................................................................................................................... 64

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The homogeneity of the structure of spunbonded nonwovens, Rita Salvado, Jacques Silvy ....... 66

Influence of pH on the molecular structure of four azo dyes, M. J. R. G. Pires, M. I. A. Ferra,A. M. M. M. B. Amaro, I. M. S. C. Gonçalves ........................................................................ 69

Development of coated conductive textile materials through in-situ polypyrrole polimerization,M. Pires, J. Lucas, M. Magrinho, R. Miguel, I. Trindade, M. Santos Silva ............... 71

Novel strategy of oxide type electrodes preparation for electrolytic treatment technologies, S.Sério, G. Martins, M. E. Melo Jorge, Y. Nunes, M. I. S. Pereira, M. J. Pacheco, L. Ciríaco,A. Lopes ............................................................................................................................................... 75

Optimization of a diluted alkaline pretreatment of rock-rose to produce bioethanol, P. Baptista,N. Gil, M. E. Amaral, A. P. Duarte ............................................................................................ 79

Development of N-doped TiO2 thin films by DC reactive magnetron sputtering for photocatalyticapplications, S. Sério, M. E. Melo Jorge, G. Martins, M. J. P. Maneira, Y. Nunes ......... 83

POSTERS

Indocarbocyanines as New Ligands for Affinity Chromatography, D. Almeida, F. Sousa, P. Almeida,R. E. F. Boto ...................................................................................................................................... 89

Comparação de métodos analíticos para a determinação do teor de sulfato e nitrato na água dasribeiras Degoldra e Carpinteira, A. M. M. M. B. Amaro, E. M. Fernandes, M. H. B. Nunes,M. I. A. Ferra, M. J. R. G. R. Pires ........................................................................................... 91

GC-MS Analysis of Essential Oil of Rosmarinus officinalis L. from PNTI, João Paulo Araújo,Arlindo Gomes, Jesus Rodilla, Paula Gonçalves, Lúcia Silva ................................................ 93

Derivatized Carboxythiacarbocyanines as New Ligands in Affinity Chromatography, R. E. F. Boto,M. Madej, P. Almeida ....................................................................................................................... 95

Biodegradability Study of Cork Boiling Wastewater, N. Canto, A. C. Gomes, R. M. S. Simões,L. Silva, A. Albuquerque .................................................................................................................. 97

Cold plasma treatment as a tool to improve recycling, Filipe Gordino, Carla Gaiolas, MárioNunes, Maria Emília Amaral, Naceur Belgacem, Ana Paula Costa .................................... 101

Anaerobic biodegradation of spent brewery grains and aromatic compounds, I. C. Gonçalves,A. Fonseca, A. M. Morão, HM. Pinheiro, AP. Duarte, M. I. Ferra ............................... 103

Estabilidade e especiação de complexos metálicos de L-lisina em soluções de cloreto de potássio,E. M. J. Catalão, J. R. da Graça .............................................................................................. 105

Electrochemical degradation of the amine 8-aminonaftalene-1-sulfonic acid: Influence of stirring andflow rate, S. Sobreira, M. J. Pacheco, L. Ciríaco, A. Lopes ............................................... 108

Antioxidant activities of extracts from Acacia melanoxylon, Acacia dealbata and Olea europaeaand alkaloids estimation, Â. Luís, N. Gil, A. P. Duarte, M. E. Amaral .................................112

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Síntese e estudo de materiais poliméricos baseados no polipirrol, M. Magrinho, A. R. Santos,D. Mota, J. Matos, A. Faria .........................................................................................................116

Electrochemical degradation of 8-aminonaphthalene-2-sulfonic acid: a comparative study between Si/BDD and Ti/Pt/PbO

2 anodes, A. S. Rodrigues, M. J. Pacheco, L. Ciríaco, A. Lopes ........ 120

Extraction, purification and structural characterization of phenolic compounds from Prunus avium,S. Santos, M. I. Ismael, J. A. Figueiredo, R. Simões, J. Rodilla, A. P. Duarte ............. 123

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PROGRAMA DA CONFERÊNCIA / CONFERENCE PROGRAMME

Thursday, 2 December

09.00 - 09.30 Registration, Anfiteatro 8.1, School of Engineering

09.30 - 10.30 WELCOME SESSION MATERIALS AND PRESENTATION OF THE UNITOF TEXTIL AND PAPER MATERIALSAna Paula Coelho Duarte, Vice-Rector for Research and Innovation andCoordinator of the Research InstituteManuel José dos Santos Silva, Coordinator of the MTP research unitRogério Simões, Principal Investigator of the Paper groupJosé Lucas, Principal Investigator of the Textile groupAna Lopes, Principal Investigator of the Fundamental Sciences group

10.30 - 12.45 SESSION IChairpersons: José Lucas, Rogério Simões and Ana Lopes

10.30 - 11.00 Innovation in the pulp and paper industryM. Naceur BelgacemÉcole internationale du papier, de la communication imprimée et des biomatériaux, GrenobleINP, France

11.00 - 11.30 Propriétés Mécaniques des NanowebJean-Yves DréanDirector of the “Laboratoire de Physique et Mécanique Textiles”École Nationale Supérieure d’Ingénieurs Sud Alsace

11.30 - 12.00 Coffee Break and Poster Session

12.00 - 12.15 Laminar Newtonian flows in square curved ducts at moderate Reynold numberJ. Malheiro1, P. J. Oliveira1, F. T. Pinho2

1 Universidade da Beira Interior2 Faculdade Engenharia Universidade Porto

12.15 - 12.30 Influence of the technology of simple and double wool fabrics in the designand performance of garmentsR. Miguel, S. Melo, M. Pereira, J. Lucas, M. Santos SilvaTextile Department, Textile and Paper Materials R&D Unit, University of Beira Interior

12.30 - 12.45 Influence of surface sizing with different binder systems on inkjet print qualityS. Sousa1, A. P. M. de Sousa2, B. M. Reis2, A. Ramos1

1 MTP Unit and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal2 RAIZ - Institute of Forest and Paper Research, Apartado 15, 3801-501 Eixo, Portugal

13.00 - 15.00 Lunch at the Great Hall of the School of Engineering and Poster Session

15.00 - 18.30 SESSION IIChairpersons: Rui Miguel, Rogério Simões and Isabel Ferra

15.00 - 15.30 Pulp Industry: Challenges and Opportunities, Processes and MaterialsSerafim Tavares(General Director of RAIZ)

RAIZ - Instituto de Investigação da Floresta e Papel, Eixo, Portugal

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15.30 - 16.00 Development of Textile CollectionsPaulo Augusto Oliveira(Administrador of Grupo Paulo Oliveira)

16.00 - 16.30 Coffee Break

16.30 - 16.45 Filmes de nanocompósitos: sua utilização na Fotoelectrodegradação do CoranteAO7T. Frade1, A. Videira1, A. Gomes1, M. I. da Silva Pereira1, O. Monteiro2, L. Círiaco3,A. Lopes3

1 C. C. M. M., Dep. Química e Bioquímica, FCUL, Campo Grande, 1749-016 Lisboa, Portugal2 C. Q. B, Dep. Química e Bioquímica, FCUL, Campo Grande, 1749-016 Lisboa, Portugal3 MTP e Dep. Química, Universidade da Beira Interior, 6201-001 Covilhã, Portugal

16.45 - 17.00 Antioxidant activity and bioactive compounds of methanolic extracts of somePortuguese shrubs speciesÂ. Luís1, F. Domingues1,2, A. P. Duarte1,3

1 Health Sciences Research Centre2 Department of Chemistry3 Faculty of Health Sciences University of Beira Interior, Covilhã, Portugal

17.00 - 17.15 Anodic oxidation of the dye Acid Orange 7 at different anode materialsD. Santos, L. Ciríaco, M. J. Pacheco, A. LopesMTP Unit and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal

17.15 - 17.30 Intelligent clothing for health careI. G. Trindade1,2, M. Pereira1,2, R. Salvado1,2, J. Lucas1,2, N. Garcia1,3, J. SantosSilva1,2, R. Miguel1,2

1 Unidade R&D de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, Covilhã6201-001, Portugal2 Departamento de Ciência e Tecnologia Têxteis, Universidade da Beira Interior, Covilhã6201-001, Portugal3 Departamento de Informática, Universidade da Beira Interior, Covilhã 6201-001, Portugal

17.30 - 18.00 Discussion

18.00 - 18.30 Poster Session

19.00 Dinner at the Wool Museum

Friday, 3 December

09.00 - 09.30 Registration, Anfiteatro 8.1, School of Engineering

09.30 - 13.00 SESSION IIIChairpersons: José Lucas, Emília Amaral and Paulo Oliveira

09.30 - 10.00 Desenvolvimento de Colecções TêxteisPaulo Augusto Oliveira(Administrador of Grupo Paulo Oliveira)

10.00 - 10.15 Hydrolysis of 3-alkyl-2-methylbenzazol-3-ium iodides: an useful reactionS. S. Ramos, L. V. Reis, P. F. Santos, P. AlmeidaMTP Unit and Department of Chemistry, University of Beira Interior, Covilhã, Portugal

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10.15 - 10.30 Assessment of bacteria-textile interactions using scanning electronmicroscopy: A study on LbL chitosan/alginate coated cottonAna P. Gomes1, João F. Mano2, João A. Queiroz3, Isabel C. Gouveia4

1 Optical Centre, University of Beira Interior, 6201-001 Covilhã, Portugal2 IBB, 3B´s Research Group, AvePark, Guimarães, Portugal3 CICS - Health Sciences Research Centre, University of Beira Interior, 6201-001 Covilhã,

Portugal4 R&D Unit of Textile and Paper Materials, Faculty of Engineering, University of Beira Interior,

6201-001 Covilhã, Portugal

10.30 - 11.00 Coffee Break and Poster Session

11.00 - 11.15 Non-Newtonian Flows in Two dimensional T-junctionsH. M. Matos, P. J. OliveiraDepartamento de Engenharia Electromecânica, Universidade da Beira Interior, Portugal

11.15 - 11.30 Comparative study of fibres for Eucalyptus globulus based paper usingexperimental characterization and 3D paper modelingJ. Curto1, E. Conceição2, A. Portugal2, R. Simões1

1 MTP Unit and Department of Chemistry, University of Beira Interior, Covilhã, Portugal2 Research Centre for Chemical Processes Engineering and Forest Products (CIEPQPF),

University of Coimbra, Portugal

11.30 - 11.45 Electrocoagulation of leachates from sanitary landfillsP. Rodrigues, D. Norma, M. J. Pacheco, L. Ciríaco, A. LopesMTP Unit and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal

11.45 - 12.00 The homogeneity of the structure of spunbonded nonwovensRita Salvado1, Jacques Silvy1

1 Universidade Beira Interior, Unidade Materiais Têxteis e Papeleiros

12.00 - 12.15 Influence of pH on the molecular structure of four azo dyesM. J. R. G. Pires, M. I. A. Ferra, A. M. M. M. B. Amaro, I. M. S. C. GonçalvesMTP Unit and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã

12.15 - 12.30 Development of conductive coated textile materials through in-situ polypyrrolepolimerizationM. Pires1, J. Lucas2, M. Magrinho2, R. Miguel2, I. Trindade2, M. Pereira2, M. SantosSilva2

1 CITEVE - Centro Tecnológico das Indústrias Têxteis e do Vestuário, Covilhã, Portugal2 Textile Department, Textile and Paper Materials R&D Unit, University of Beira Interior

12.30 - 13.00 Discussion

13.00 - 15.00 Lunch at the Great Hall of the Faculty of Engineering and Poster Session

15.00 - 17.00 SESSION IVChairpersons: José Lucas, Rogério Simões and Lurdes Ciríaco

15.00 - 15.30 Cellulose-silicahybrids - a universal template for new cellulose-derivedmaterialsDmitry EvtuguinDepartment of chemistry, University of Aveiro, Portugal

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15.30 - 15.45 Novel strategy of oxide type electrodes preparation for electrolytic treatmenttechnologiesS. Sério1, G. Martins2, M. E. Melo Jorge2, Y. Nunes1, M. I. S. Pereira2, M.J. Pacheco3,L. Ciríaco3, A. Lopes3

1 CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia da UniversidadeNova de Lisboa, 2829-516 Caparica, Portugal2 Dep. Química e Bioquímica/Centro de Ciências Moleculares e Materiais, FCUL, Campo GrandeC8, 1749-016 Lisboa, Portugal3 MTP Unit and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã,Portugal

15.45 - 16.00 Optimization of a diluted alkaline pretreatment of rock-rose to producebioethanolP. Baptista1, N. Gil1, M. E. Amaral1, A. P. Duarte1

1 MTP Unit, University of Beira Interior, 6201-001 Covilhã, Portugal

16.00 - 16.15 Social networks in the research teams: Impact and future trendsMadalena Pereira, Rui Miguel, José Lucas, Manuel Santos SilvaTextile Department, Textile and Paper Materials R&D Unit, University of Beira Interior

16.15 - 16.30 Development of N-doped TiO2 thin films by DC reactive magnetron sputteringfor photocatalytic applicationsS. Sério1, M.E. Melo Jorge2, G. Martins2, M. J. P. Maneira1, Y. Nunes1

1 CEFITEC, Dep. Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa,2829-516 Caparica, Portugal2 Dep. Química e Bioquímica/Centro de Ciências Moleculares e Materiais, FCUL, Campo GrandeC8, 1749-016 Lisboa, Portugal

16.30 - 17.00 DISCUSSION and FINAL SESSIONChairpersons: Manuel Santos Silva, José Lucas and Rogério Simões

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SESSÃO DE ABERTURA

TEXTILES AND PAPER – INNOVATIVE MATERIALS AND PROCESSESManuel José dos Santos Silva, Coordenador Científico da Unidade de Materiais Têxteis ePapeleiros, Universidade da Beira Interior.

SESSÕES CONVIDADAS

INNOVATION IN THE PULP AND PAPER INDUSTRYM. Naceur BelgacemÉcole internationale du papier, de la communication imprimée et des biomatériaux, GrenobleINP, France. PROPRIÉTÉS MÉCANIQUES DES NANOWEBJean-Yves Dréan (Director of the “Laboratoire de Physique et Mécanique Textiles”)École Nationale Supérieure d’Ingénieurs Sud Alsace, France. PULP INDUSTRY: CHALLENGES AND OPPORTUNITIES, PROCESSES ANDMATERIALSSerafim Tavares (General Director of RAIZ)RAIZ - Instituto de Investigação da Floresta e Papel, Eixo, Portugal. DEVELOPMENT OF TEXTILE COLLECTIONSPaulo Augusto Oliveira (Administrador of Grupo Paulo Oliveira).

CELLULOSE-SILICA HYBRIDS - A UNIVERSAL TEMPLATE FOR NEW CELLULOSE-DERIVED MATERIALSDmitry EvtuguinDepartment of Chemistry, University of Aveiro, Portugal.

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Textiles and Paper – Innovative Materials and Processes M.J. Santos Silva

University of Beira Interior Abstract In this fast changing world, highly qualified human resources are the main drivers of evolution and development of societies and of competitiveness among them. Textile and paper materials have always been linked to human activity. They promoted and followed its development since the dawn of mankind until the present day. Research and development have allowed the emergence of new materials and processes, not forgetting services that make textiles and paper continue to play a key role in the European economy, producing goods with higher value added, that contribute to the competitiveness of their sectors. Introduction As we did in previous years, we are holding another Symposium of Textile and Paper Materials. Its main goal is to reflect and disseminate the scientific activity carried out by the unit and discuss with the community the program guidelines for research to be developed. Last year we discussed the future of teaching and research in the areas of textiles and pulp and paper, which justify the rationale of our unit. This year, the Organizing Committee has proposed the theme "innovative materials and processes", in view of knowledge that is being produced, and also because they constitute engines of economic development and competitiveness. In this world of rapid change and uncertainty, where everything is questioned, there are, however, some parameters that are considered pillars of the economy and competitiveness of countries and regions. In the knowledge society in which we live, we must bear in mind that the greater the asset in human resources are, the more educated and skilled they are, the greater the wealth of the organization in which we live. The use of textile and paper materials Textile and paper materials are – and I think they will continue to be – essential products to society. The use of textile materials for man protection dates back to the beginnings of humankind. Paper has always been a fundamental tool for ensuring communication among men. To support writing or as packaging material, paper became an indispensable product. It allows transmitting information and provides support to the registration of intellectual and artistic creation, which is linked to the progress of various civilizations. Nowadays the consumption of textile and paper per capita is directly related to the development index of a given society.

The Research Unit of Textile and Paper Materials is therefore linked to two materials of vital importance to humanity. Hence, we have the responsibility to continue to produce knowledge and transfer it to enterprises to be turned into innovation and added value to the economy. The financing of research and development Today, more than ever, the University/Enterprise cooperation is indispensable to progress. If, until recently, in Portugal, most of the research produced was financed by public funds, this trend has been changed with the increasing investment of the private sector, like most developed countries, which reached 50% in 2009, with a tendency to rise. According to EUROSTAT, the number of people allocated to R&D activities, both in textiles (= 0.1), as in paper (= 0.2), is rather low, as well as their investments. In a challenging and changing world, in face of the merge and closure of enterprises, problems of supply of raw materials and increasing demands on the environment and quality of final products, in addition to the entry of new markets such as China, last October Lisbon hosted the VI Ibero-American Congress on Research in Pulp and Paper, together with the XXI Meeting of TECNICELPA, whose theme was "New Paradigms of Pulp and Paper". Of the various interventions presented there, we can understand that, although it is undergoing a complex socio-economic period, the sector has managed to overcome the crisis in our country. The forest industry Unlike the Nordic countries, which have faced problems in obtaining raw materials (originating from Russia), Portugal has managed to diversify the sources from countries like Mozambique and South America, besides its major supply from the national forest. The forest industry is the basis of a sector of the economy that heavily contributes to the national GDP (3.2%) and industrial GDP (12%) and that represents 11% of the national exports, with an increase of 10.9% between 2005 and 2009, well above the global average which was 1.6%, apart from being a sector that contributes with one of the greatest added value for the economy. Despite the effort in creating legislation, especially in the year 2008, there is still much to do in the forestry sector, in a country where most of soils are suitable for forest. It is recognized that the most appropriate management and valuation of forestry resources is due to the leading producers of pulp (Portucel Soporcel/; Altri, SGPS, SA (Celbi)), but we would gain much more from a proper management of the forest in its entirety. It is well known that Latin America produces pulp of good quality at low prices, taking into account the low cost of the raw materials and also the scale factor. But

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when that pulp enters Europe or China it is necessary to take into consideration the costs of transportation, so most of the time it is not competitive. Thus, with the expanding Chinese market, despite on-going investment in that country and the proximity of the European market, Portugal continues to have a good opportunity to grow in the markets of pulp and paper, also taking into consideration the quality of the manufactured products. The sector has continued to invest heavily, as is the case, for example, of the recently inaugurated plant of Portucel in Setubal, which stands as the largest producer of writing paper in Europe. Despite its size, Portugal currently holds the 7th place worldwide in the production of bleached pulp and 17th place in paper production. In 2009 (EUROSTAT), the pulp sector in Portugal has a coverage rate (exports/imports) of 971%, and paper and paperboard has a rate of 107%. New fields of research and innovation The depletion of fossil energy resources and the rising price of oil, with all the existing problems in the environment, polluted air and water, poor management of water resources and waste and the proclaimed greenhouse gases (CO2 responsibility) paved the way for a new economy based on products of biological origin. Nature, through the infinite-dimensional machine of photosynthesis, produces carbohydrates and oxygen from water, carbon dioxide and solar energy. Human beings have always survived by using products provided by nature, from food to clothing or other more sophisticated goods that were obtained through successive transformations of natural materials, development of knowledge and taking advantage of the surrounding environment. While we seek alternative energy sources, such as wind and sun, we must take into consideration the energy we can get through the plant biomass, obtained, as referred, through photosynthesis. In fact the forestry production can, among others, give the pulp (and at the outset the production of energy) and paper and can be converted into products that will gradually replace petroleum products. Biorefinery is now an undeniable fact, allowing to obtain the most varied products through different processes: fuels and lubricants, alcohol, sugar, acids, etc., not forgetting the basis of natural polymers (cellulose, hemicelluloses and lignin) which in turn give rise to an increasing number of new materials with high added value, the nanoscale, which is a strong field of research and innovation. Plant biomass may be the oil of the future, contributing to a sustainable development of humanity and to a world with greater geopolitical stability. UBI’s contribution Since the early 1980s, UBI has been giving great importance to teaching and research in the area of pulp and paper in conjunction with enterprises and technicians of the sector and their associations. From 1991, with the

creation of the Research Unit of Textile and Paper Materials, research component has been increased, promoting the training of PhD students and building and equipping an enviable laboratory structure. The term paper has not been attractive to young people and paper engineering petered out in our institution, as has happened all over Europe. However, I believe that we must strive to attract human resources from other areas and continue to develop collaborative research with industry. Fortunately, the level of scientific contribution of the Faculty of Sciences, in particular of the Departments of Chemistry and Physics, has been growing, as well as in the Faculty of Engineering, through the Department of Electromechanics, which have been working on several issues related to materials processes and services. New trends for the textile industry Indeed, in this world of change and uncertainty, where is the pure product? There is always a mix of product, service and transformation process that will continue to add value up to the final consumer. We can see what the printing industry represents in terms of added value or the value chain ranging from a textile fibre to a high-fashion model who will wear an elegant woman in a ceremony of high society. All studies point towards the people’s tendency to concentrate in urban centres, which will become stronger in the coming years. What do we see while walking down the streets or avenues of any metropolis? Storefronts, shops, malls, etc., full of light and colour, where most of the products displayed to attract consumers are textile products, graphic impressions, of the most varied colour and exquisite packaging, in addition to magazines and books we find there. The consumption of textiles and clothing has been massifying, but it expresses simultaneously individualization features. Textile and clothing industry have faced structural changes in Europe in recent decades. The shift of means of production to countries with low labour cost has been constant, which inspires at the same time a huge competition in the sector. However, these activities still represent one of the largest industrial sectors and continue to be of the utmost social and economic importance for Europe. The three main areas are clothing, with 46% of total production, home textiles, with 32%, and technical textiles with 22%. (http://www.euratex.org). If Europe wants to continue to play a leading role in the global market, it will have to map out strategies to the sector. Thus, we have been witnessing a transformation, and I believe that this trend will grow in the future, with a sharp growth in aspects related to creativity and design fashion, quality, innovation and reorganization in production with the verticalization and integrating of marketing and branding. The need of verticalization and differentiation of industry has become more pressing with the

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liberalization of the textile markets and the abolition of import quotas in 2005. We are facing a new paradigm, in which business differentiation is accomplished by specializing in certain products and by its quality and functionality, but also for the flexibility and responsiveness to the market requests. Often and increasingly, it's not just the price of a product that counts, but the rapid response capability of the entire organization. Key factors for the future Nowadays, a product as a product itself no longer exists. What we have is a mix of products and services and quality management throughout the organization. The challenges of this new organizational order require adequate training of staff at the highest level and a workforce increasingly qualified. Leading countries were aware of this and continued to train young people for new challenges in order to have the largest percentage of the value added of production/marketing chain, regardless of where the article is produced. Let us consider what happened in the United Kingdom, Italy, in France, or even in the United States of America: the vast majority of Textile Engineering Schools that were developed until the 1970s and 1980s has resulted in Design Schools, Fashion, Marketing, etc., without neglecting the preparation of students in practical aspects, essential for the understanding and easy integration into the world of work. These schools continue to be placed in the heart of the city and its shopping centres, in order to awaken students to the world and trends in large cities, encouraging them to the creative aspects. However, alongside this transformation, they did not neglect the preparation of scientists and researchers in the areas of textile engineering, materials, chemistry, electronics and informatics, because the only way to innovate is by research and knowledge production. Basic and applied research is indispensable, as well as the transfer of their results for companies that must adapt them and produce, launching new products in the markets with added value. The differentiation among companies and their struggle to have an added value, simultaneously with the consumption decrease in the areas of clothing and home textiles, which may become more pronounced with the current crisis, has led companies, and also consumers, to redirect their concern for other products that require an increased research effort, such as technical textiles. Thus grows the interest and the development of smart textiles, textile applications in health and wellness, clothing for the practice of sport, for protection at work and also in outside use. In Europe and Portugal, the growing number of companies specializing in niches market in the field of functional and innovative textiles became more pronounced, even at the level of the garment, contributing to the social and economic progress of the textile and clothing industry.

All these new types of textiles require an increasing investment in research. The growth in demand and the longing for a better quality of life have contributed to the emergence of an increasing number of prototypes of smart textiles and an increase in scientific development. Clothing, home textiles and textiles for automobiles, which can be considered as the more traditional, have attracted attention. Recently the areas of textiles, health communication, show business and fun industries joined them. In fact, the world of textiles is rapidly transforming. The Centenary Conference of the Textile Institute was held in Manchester last 3 and 4 November. Contributions and assistance throughout the event demonstrated the dynamics of change that is operating globally, particularly in comparison with programs in the same Conference, a few years ago. Experts made several predictions of changes that may arise and mark the global village in the coming decades. Anyway, culture, education, training and knowledge production are key factors to be taken into account in the forecast of industry’s future. Consumers respond to markets and cultures create their own markets. The citizens of the 20th century had different attitudes from those of the 21st century and we should ask ourselves about how things will be in ten years! We should dwell on the predictions coming from different sides and try to develop strategies for research and training of young people through new curricular organizations, helping to define new careers and education methodologies, to invest and even to influence government policies. What does the future hold in new materials, fibres and fabrics (smart textiles) in the field of design, production and control technologies in different types of markets? Certainly the scientific and technological development will contribute to the emergence of new materials, through design and product development processes, with a strong component in the field of information technology will lead to new ways of using and handling textiles. In this chain we must not forget the part of the trade, marketing and distribution and its direct relationship with the consumer. There is an absolute need for a profound research involving the consumer and the designer. The involvement of the consumer in the design of textile products is of utmost importance, as well as collaboration between the University and industry, which certainly will bring significant gains for all. The world economic forum recently published the Global competitiveness report 2010-2011. Although the crisis has affected many countries in Europe, the truth is that, overall, Europe continues to have a good performance, being one of the most competitive regions in the world. The performance difference between the US and the EU is largely due to the structural weaknesses of European economies, coupled with the lower investment in education, research and development in the business and high technology sectors. For example, the US invest 2.9% of GDP in higher education, while in the EU this investment is around 1.2% (EUROSTAT).

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The business sector, with regard to investment in R&D, represents 1.87% of the US GDP, while in the EU is around 1.17%. The increased competitiveness of the American economy is reflected by the fact that both GDP per capita and per hour of work are higher than in the EU. The sectors that contributed most to the increase in productivity in the EU between 1999 and 2007 were manufacturing, transport and telecommunications. However, labour unit costs are still high on the EU compared with USA, mainly in sectors such as food industry, textile industry, transport and electrical equipment. Anyway, textile, pulp and paper industries continue to have an important role in European and world economy. Conclusions Over time, several factors led and influenced the productivity and competitiveness of countries, regions and societies. With Adam Smith, attention was given to specialization and division factors at work. Neoclassical economists emphasized the investment in human capital and physical structures. More recently, the focus has been placed on education, research, innovation, technological progress, in the state of health of the population, macroeconomic stability, the quality of governments and on the efficiency of markets, among other factors. The abovementioned report on competitiveness has grouped in twelve pillars the different components that contribute to it. But education, research and innovation are the most relevant to the more advanced economies, which lead to the frontiers of knowledge. Innovation, both public and private, entails investment in education, research and development, openness and cooperation among universities and enterprises and the protection of intellectual property. Europe and Portugal are moving towards a strategy of knowledge-based economy, but despite the progress that has been achieved in recent years there is still a long way to go to make this real. Our research unit has attempted to contribute to the variation desired in two important sectors for the national economy, with different characteristics, but with a common need: the need to invest more in research and development, to make them even more competitive. We must therefore make an effort to mobilize additional resources, both material and human, and get closer to the industrial sectors. We also want the business sectors to see us as partners with whom it is worthwhile to work. In this symposium we hope that the presentation of research undertaken may lead to new materials and processes, to the promotion of innovation and to a closer relationship between UBI and enterprises. Thanks again to everyone for participating in this Symposium. I wish you a fruitful work during these two days and a pleasant stay for our guests at UBI and in the city of snow. Thank you.

References 1. Borneman, J., Turning innovation into consumer

products, Textile World, Vol. 154 No. 10, pp 36-40, 2004.

2. Floresta - Espaço de Futuro – 2008 – MADPR, January 2009.

3. Kim, E. and Johnson, K.K.P, Forecasting the U.S. fashion industry with industry professionals – part 1, Materials and design, Journal of Fashion and Management, Vol. 13 No. 2, pp. 256-267, 2009.

4. New Paradigms in the Pulp and Paper Industry, XXI TECNICELPA Conference and Exhibition and CIADICYP, VI Iberoamerican Congress on Pulp and Paper Research, 12-15 October, Lisbon, Portugal.

5. O'Connor, K., How Smart Is Smart? T-shirts. Wellness and the Way People Feel About Medical Textiles, Textile, vol. 8, Issue 1, pp. 50-67, 2010.

6. Schwab, K., The Global Competitiveness Report 2009-2011, World Economic Forum, Geneva, Switzerland, 2010.

7. Schwarz, A. et al., A roadmap on smart textiles, Textile Progress, Vol. 42, no. 2, June 2010, pp. 99-180, 2010.

8. Sideri, E., The human age, AATCC Printing Symposium, "A Digital Reality", New York, May 2005.

9. Textiles Global Vision, The Textile Institute Centenary Conference, 3-4 November 2010, Manchester, U.K.

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The Paper group in the Unit of Textile and Paper materials Rogério M. S. Simões1

1UMTP and Department of Chemistry, University of Beira Interior, Covilhã, Portugal The Paper Group team is composed by 15 members with a PhD degree, two of them as collaborators. The research group accepts 4 Ph.D. students and several Ms. students. The general objectives of the group are: (1) to carry out applied and fundamental research on pulp and paper materials; (2) to investigate the potential of wood and non-wood raw-materials as source of chemicals, energy and renewable composite materials. The specific topics under investigations are as follows:

Wood and non-wood plants: Papermaking potential Sources of chemicals, biofuels and

composite materials (Biorefinery) Chemical pulping Bleaching of chemical pulps, including

biobleaching Refining of chemical pulps, including

biorefining Papermaking chemistry, including fiber

modification Paper production, including paper modeling Surface paper modification and characterization Paper physics and printability Paper recycling Effluent treatment

Regarding to the bioactive compounds from wood and non-wood species, the screening of different shrub species existing in the Portuguese forests will be continued, in order to evaluate their potential as a source of biological active compounds. Crude extracts, fractions and pure compounds will be screened for antimicrobial activity, potential antimutagenicity and genotoxicity and citotoxicity. Non-wood species like Erica spp., Cistus spp., Cytisus spp and Pterospartum tridentatum are under investigation. The lignocellulosic residues were submitted to solvent extractions, chromatographic separations, isolation of compounds, identification and chemical/biological characterization. The isolated and identified compounds could be used as high value chemicals, nutraceuticals, etc. We also intent to transform some natural compounds, to obtaining new natural derivatives with insecticidal activity, antifungal, antibacterial and antiparasitary activity. Some of these compounds have potential to be used as natural pesticides. Sugar as natural source will be used as starting material for promote the synthesis of new compounds, which can act as insecticides or antiviral agents.

The bioethanol project intends to implement a bioprocess for the production of bioethanol from forestry residues, which comprises the raw materials pretreatment and the biological conversion of sugars to ethanol. The study was started with the optimization of the process variables in biomass pretreatment, using different approaches: dilute acid and alkaline treatments. The pretreated biomass is hydrolysed by a mixture of cellulases and β-glucosidases from several microorganisms strains. Different microorganisms are tested for sugar fermentation to ethanol. In the scope of biorefinery, we are initiating the evaluation of the potential of the steam explosion process for chemicals and nanofibril production, using wood and non-wood materials. In the pulping area, a FCT project has the objectives of to identify and evaluate the extractives in wood from Eucalyptus globulus, to study their variation with seasonality, tree age, and to develop a prototype to test pretreatments for extractives removal, in order to decrease their negative influence in pulp and paper production. Regarding to pulp refining, we are studying the effect of enzyme-assisted refining for pine and eucalypt bleached pulps. Different commercial mixtures of cellulases, β-glucanases and xylanases are used at different charges and reaction times. The aim is to study the effect on the drainability properties, pulp resistance and morphological and physic-chemical characteristics of the fibers. The effect of enzyme treatment on the pulp refining ability vs. energy savings will be observed. Previous research works leading to the modelling of the refining process emphasized the importance of flocculation and rheological behaviour of the fibre suspension. These two specific points depend of such factors as consistency, temperature and pH, but are above all dependent on fibre morphological characteristics (specifically fibre length, shape factor and rigidity). This research line intends to establish models relating apparent viscosity with different fibre parameters in different fibre sources. Regarding to paper modelling, we are implementing a innovative tree dimension paper model. Departing from a sedimentation paper model like the KCL-PAKKA model, a three-dimensional random network structure of paper is formed. Fibre flexibility, dimensions and collapsibility are introduced in the model which gives realistic predictions for many paper properties. The model is developed using a MATLAB implementation and a cellular automata framework and presents several original contributions, such as allowing the study of fibre collapse influence.

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Experimental work was also carried out to validate the model, using the most important fibres used in office paper production. In the paper field, a FCT project aims to develop and implement an optical method, based on retrodiffusion and transmission of the laser radiation, in order to measure and analyse the structural characteristics of the paper sheet, on a microscopic level. An experimental optical scanning system, for non-contact data acquisition, will be developed and implemented to scan at once both sides of the paper sheets. The innovation of the proposed method is related with the fact that the measurements of the fibre orientation, in the surface and in the bulk, and the mass density are point correspondent for both paper sides. Regarding to paper surface modification, the main aim is to apply cold plasma, using coupling agents, to modify the paper surface, in order to improve the characteristics and the adhesion on other materials. Other objective is to improve the wet-strength paper properties by applying only cold plasma treatment or cold plasma associated to diverse coupling agents. This treatment is applied on a bleached pulp of Eucalyptus globulus subjected to several recycling cycles. In the scope of a QREN project, involving several research units and industrial partners, we intend to develop high performance printing papers. The contributions of UBI are: (1) develop new uncoated papers for digital and offset printing processes, (2) evaluate the penetration of several inks into the paper, using cross-section image analysis, (3) understanding/interpretation of the ink/paper and toner/paper interaction, (3) interpretation and explanation of the relationship between surface characteristics, ink penetration and print quality. In the environmental filed, we are working in three areas: in the kinetic of textile dye degradation by ozone, in the cork wastewater treatment, and in the characterization, valorization and integrated treatment of agro-industrial effluents. Regarding to dyes, in a previous study, the very fast decolourisation kinetic of textile dyes by ozone (pH 2.5 and radical scavenger) was established, using a continuous quench-flow system (milliseconds time scale). The present study intend to investigate the influence of pH, in the range 2.5 – 8, on the decolourisation kinetic, using two textile dyes: acid green 27 (anthraquinone) and acid orange 7 (azo). The decolourisation rate is extremely fast and increases with the pH, giving second order rate constant at 10ºC in the range 2.70 x 104 –4.68 x 106 M-1 s-1, for the acid orange 7. This correspond to decolourisation extents in the range 61—96 % for 144 milliseconds.

One FCT project aims to study the “Integrated treatment of cork processing wastewaters for potential reuse”. Portugal is the World’s leading country for cork production and transformation. Close to 80% of the income resulted from cork oak exploitation depends on cork value, which closely related with the acceptance of cork as natural premium raw material for stoppers. However, the wastewaters resulted from the boiling stage (about 400 l/ton of cork) are a dark liquor containing corkwood extracts, several of them are other toxic or recalcitrant compounds. This project is addressed to study an innovative depuration process integrating membrane technologies, ozonation and constructed wetlands. The objectives of the QREN project, intitled “Characterization, valorization and integrated treatment of agro-industrial effluents” are to consolidate the laboratorial infra-structure in terms of analytical equipment, and characterization, valorization and integrated treatment of agro-industrial effluents, namely olive oil wastewater and whey (“soro do leite”). The FCT and QREN financed projects are:

Project FCT: PTDC/AGR-CFL/110419/2009 (ISA, UBI, outros)

Project FCT - PTDC/CTM/102831/2008 Project QREN: PADIS Project FCT: PTDC/AGR-AAM/102042/2008 Project Mais-Centro: ID:36120

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THE TEXTILE SCIENCE WORKING GROUP IN MTP UNIT: PRESENT AND FUTURE RESEARCH

José M. Lucas, Coordinator of the Textile group Textile Department, Textile and Paper Materials R&D Unit, University of Beira Interior

Objectives Applied and Fundamental Research on Textile Materials in collaboration the members Paper and Fundamental Sciernces in a multidisciplinary way Team PhD: 14 PhD students: 7 Technicians: 5 Present and Future Research Projects Following the guidelines of European Technology Platform for the future of Textiles and Clothing:

• From Commodities to Specialty Products • New Textile Applications • From Mass Production Customisation

The Textile Group is carrying out the following subprojects: PTDC/EBB-BIO/113671/2009 Skin2Tex_Old peptides with new faces: A new strategy to develop non-toxic antimicrobial textiles for healthcare applications.

Team: Isabel C. Gouveia Ana Palmeira-de-Oliveira Luíza Granadeiro Mariana Henriques Ana Paula Gomes Erhan Piskin.

CICS – Centro de Investigação em Ciências da Saúde, da Universidade da Beira Interior, Centre of Biological Engineering e IBB- Institute for Biotechnology and Bioengineering, Braga, da Universidade do Minho e R&D Center for Bioengineering Universidade de Hacettepe, Ankara, Turquia Unidade MTP, Universidade da Beira Interior. Aproved funding: 115,117.00 €.

ICT_2009_02_038_2050 Biotechnology and nanotechnology as effective tools for the development of new bioactive and antimicrobial textiles for health and cosmetic applications. Programa QREN – Quadro de Referência Estratégico Nacional, MaisCENTRO – Programa Operacional Regional do Centro, Eixo Prioritário 1 – Competitividade, Inovação e Conhecimento, SAICT – Sistema de Apoio a Infra-estruturas Cientificas eTecnológicas.

Team: Isabel C. Gouveia Ana Palmeira-de-Oliveira Luíza Granadeiro Mariana Henriques José Martinez de Oliveira João A. Queiroz Ana Paula Gomes Duarte Leite.

CICS – Centro de Investigação em Ciências da Saúde, da Universidade da Beira Interior, Centre of Biological Engineering IBB- Institute for Biotechnology and Bioengineering, Braga, da Universidade do Minho Centro Hospitalar da Cova da Beira Playvest SA Unidade MTP, Universidade da Beira Interior. Financing: 320,389.87 €. Waiting for aproval TEXTILE AND CLOTHING MASS CUSTOMISATION

Some of the objectives of this project are: Methodologies of simulation and training. Design and product development. Co-design producer/consumer. Demands and functionalities of new products, communication strategies and benchmarking methodologies. Morphology and

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anthropometry of human body. Objective testing and quality control equipment through simulation. Guidelines to the development of an e-commerce platform for customized garments. E-learning project for the long life training clothing industry staff members.

UBI team: Rui Alberto Lopes Miguel José M. Lucas Manuel José S. Silva Madalena Pereira Francisco G. F. Franco Rita Salvado Elsa Lima Financing: FCT, MTP unit - 2007 a 2010. NEW APPLICATIONS OF HIGH TECH TEXTILES

Development of functional and wearable textiles:

1) New textiles to improve human being performance

2) Wearable textiles and garments

Financing: FCT, MTP unit - 2007 a 2010.

UBI Team: Rui Alberto Lopes Miguel Isabel Trindade José M. Lucas Manuel José S. Silva Luisa Rita Salvado Madalena Pereira Nuno Garcia MICROESTRUCTURA, CARACTERIZACIÓN Y PROPIEDADES DE LAS FIBRAS DE POLI(ÁCIDO LÁCTICO) Subproyecto 2: Caracterización, Propiedades y Aplicaciones de las Fibras de Poli(ácido láctico)

Development of woollen fabrics, this is, fabrics in which wool fibres are one component, having added functionalities coming from the blend of wool and PLA fibres, having specific and complementary properties according the end use.

Principal Investigator: Diana Cayuela Marín

UPC – Universidad Politécnica de Catalunia, Terrassa, Espanha. Subproject 2 Principal Investigator: Albert Maria Manich CSIC – Consejo Superior de Investigaciones Científicas, Barcelona, Espanha. Financiamento: Programa Nacional de Materiales del Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica – Espanha.

UBI Team: Rui Alberto L. Miguel Manuel Santos Silva Francisco G. F. Franco José M. Lucas Fitecom Team: João Carvalho Projecto Mobilizador PT 21 - POWERED TEXTILES SÉCULO 21; PPS – HIGHTECH FASHION/FASHION FABRICS Programa QREN – Quadro de Referência Estratégico Nacional Sistema de Incentivos à Investigação e Desenvolvimento Tecnológico (SI I&DT) Projectos de I&DT Empresas Mobilizadores

Promoted by: CITEVE - Centro Tecnológico das Indústrias Têxtil e do Vestuário de Portugal Co-Promotion: Universidade da Beira Interior – Unidade de I&D Materiais Têxteis e Papeleiros, Departamento de Ciência e Tecnologia Têxteis; FITECOM - Comercialização e Industrialização Têxtil, S.A.

Project responsible: CITEVE UBI project responsible: Rui A. L. Miguel Other UBI team members: José M. Lucas; Madalena Pereira; Rita Salvado; Isabel Trindade Total budget: 687,451.00€ (Projecto) UBI budget: 503,629.00€ (Projecto) 01/Jan/2011 - 31/Dec/2013

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MEDTEX- INTELLIGENT TEXTILE COATINGS FOR BEDRIDDEN AND PERSONS WITH REDUCED MOBILITY

These intelligent textiles will be developed in order to potentiate its application in different areas. The main objective of this project it to develop biomedical textiles – an electro textile intelligent system having maximized biofunctionality and thermophysiological comfort.

UBI team: Nuno José Ramos Belino FEMININE UNDERWEAR AS AN HYGIENIC TOOL

This Project aimed to develop feminine underwear with an optimized hygienic function, by applying textile materials that minimize the interaction between the textile and the skin, preserving by this way the natural genital ecosystem. The main objective is the development of feminine pants according to the principles of the absorbent hygienic products

UBI team: Luisa Rita Salvado Rui A. L. Miguel

INTERACTIVE TEXTILES This Project aims to develop smart textiles to integrate in clothes and interior products that allow the interaction between the user and the environment. The main objectives are the development of textile products to integrate in domotic, health monitoring systems and public spaces.

UBI team: Luisa Rita Salvado Pedro Araújo Andreia Rente DEVELOPMENT OF MULTIFUNCTIONAL FASHION COMPLEMENTS

The objectives of this research work is the development of new fashion complements or transformation of existing ones, improving multifunctionality by using design concepts, 2D and 3D garment modelling techniques and garment making techniques. The main objective of developed products is based in increasing quality of life of individuals as a function of observed needs in the present market and expertise future previewing.

UBI team: Madalena Pereira Rui Alberto Lopes Miguel Rita Salvado José M. Lucas

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The Fundamental Sciences Group in the Unit of Textile and Paper Materials

A. Lopes

UMTP and Department of Chemistry, University of Beira Interior, Covilhã, Portugal

The Fundamental Sciences Group team is composed by 17 members with a PhD degree, being 15 from the Department of Chemistry, 1 from the Department of Mathematics and 1 from the Department of Mechanical Engineering, 1 Post-Doc, 5 PhD students and 5 students with a grant. The main objectives of the Group are:

Applied Research on Textile and Paper Materials, in a multidisciplinary way

Fundamental Research in Chemistry and Physics and Fluid Dynamics, related directly or indirectly with Textile and Paper Materials and Industries

Based on these objectives, the following keywords were defined for the research developed by the Group:

Textile Dyeing and Effluent Treatment Nanomaterials New Anode Materials Chemical Characterization of Textiles and Plants Functional dyes Computational Rheology

The work developed by the Group is grouped in several different projects, described bellow in a succinct way. Project “Cleaner Environment”

This project involves 10 PhD people from the Department of Chemistry and has connections with researchers from other Institutions, namely, IST, FFCUL, FCT-UN and UE The purposes of the project are:

1. To reduce contaminants rejected in the effluents of several industries, combining different technologies: Aerobic and anaerobic biotechnologies Electrochemical techniques Photocatalytic oxidation and sorption processes

2. To study physical-chemical properties of dyes, namely dissociation constants and solubility.

The development of this project, that involves 5 different tasks, is based on the following keywords: Azo dyes; biodegradation; electrochemical oxidation; catalytic oxidation; acid dissociation constants; solubility of dyes. Task 1: Anaerobic biodegradability of xenobiotics Anaerobic biodegradation of residual xenobiotics (dyes and levelling agents) were carried out in UASB (Upflow Anaerobic Sludge Blanket) reactors. Depending on the type of carbon source and the hydraulic retention time a higher or lower decolourization rate was obtained

Task 2: Aerobic biodegradability of xenobiotics Biodegradation of aromatic amines and dyes was performed with several inocula in batch tests. The influence of type and position of substituent groups in the aromatic ring was studied and it seems that these factors have a significant influence on their biodegradation.

Task 3: Electrochemical degradation of persistent pollutants The electrochemical degradation of dyes, aromatic amines, pharmaceutical compounds and leachates from sanitary landfills was performed, using as anode materials boron-doped diamond, tin oxide, lead oxide and composite oxides. All products studied have shown very high degradation rates and, in most of the studies, almost complete mineralization were achived.

Task 4: Photocatalytic oxidation and sorption of aromatic amines The objective of this task is to produce a catalytic-adsorbent system to assess photocatalytic oxidation of persistent pollutants.

Work is being developed mainly in the following aspects: TiO2 anatase doped nanopowders preparation Nanopowders impregnated textiles preparation Soluble aromatic amines photodegradation kinetic studies under visible and UV light

Effects of doping TiO2 nanopowders with metal cations

Task 5: Acid dissociation constants and solubility of textile dyes Dissociation constants of several dyes have been determined, spectrophotometrically, in aqueous sodium chloride solutions, at various ionic strengths, and thermodynamic equilibrium constants could be evaluated from extrapolation to zero concentration. Studies concerning the determination of dyes solubility, at different temperatures, are also being carried out. Project “Green Chemistry in Medicinal Plants from

Angola”

This project includes 1 PhD from the Department of Chemistry, 3 PhD from the University of Luanda, Angola, 1 PhD from the Federal University of Alagoas, Brazil, and 2 PhD. students. The work developed can be described by the keywords green chemistry, medicinal plants and biological activity, and comprises 3 tasks. The main objectives of the project are:

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Chemical evaluation of the extracts already existing from different plants

Spectroscopic characterisation of the isolated compounds

Evaluation of biological activities Task 1 – Preparation and chemical evaluation of the extracts The extracts were fractionated by column chromatography, flash chromatography, tin layer chromatography and HPLC with suitable solvents and pure compounds were. They compounds were identified by means of NMR techniques.

Task 2 – Spectroscopic characterisation of the isolated compounds The compounds were fully characterised by means of IR, UV, 1H NMR, 13C NMR, GC-MS and 2D - NMR (HMBC and HMQC etc.).

Task 3 – Evaluation of biological activities The biological activities against tropical diseases of the extracts and compounds isolated in tasks 1 and 2 were evaluated. Project “New Stationary Supports for Affinity

Chromatography”

The people involved in this project are: 2 PhD from the Department of Chemistry, 1 post-Doc and 2 BIC grants. Several collaborators from the CICS Unit, from UBI, and from the University of Trás-os-Montes e Alto Douro are also involved in this project.

The keywords for the project are affinity chromatography, cellulose, cyanine dyes and protein purification, and its objective consists on:

Development of new stationary chromatography supports based on cellulose materials and monoliths, derivatized with cyanine dyes, able to interact selectively with proteins.

Figure 1 presents a schematic view of the project that comprises 3 tasks. Task 1: Synthesis and characterization of new cyanines The synthesis and fully characterization of reactive or funcionalizated cyanines by new methods or methods adapted from the literature was performed. Some new reactions were also developed.

Task 2: Immobilization of cyanine dyes onto cellulosic supports and monoliths The influence of different concentrations on the immobilization of cyanine dyes onto cellulosic supports and monoliths by optimised dyeing methods was studied. The cellulose derivatized was qualitatively and quantitatively characterised. Task 3: Studies of affinity chromatography for standard proteins The resulting dyed matrices were used as specific supports in affinity chromatography for standard proteins. The influence of mobile phase composition on the chromatographic behaviour of this biomolecules was studied.

Figura 1. Scheme of the project “New Stationary Supports for Affinity Chromatography”.

Sample application (loading)

Protein adsorption

Washing (removal of unbounded

material

Elution of desired protein

Ligand immobilization onto cellulosic

materials

Regeneration/cleaning

SSIIMMPPÓÓSSIIOO UUMMTTPP 22000099

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Project “Rheology and Computational Fluid Dynamics”

This project involves 1 PhD from the Department Mechanical Engineering, 1 PhD from the Department of Mathematics and 3 PhD students. This team cooperates with researchers from the Mechanical and Chemical Engineering Departments of the Faculty of Engineering of the University of Porto (FEUP), Department of Polymer Engineering of the University of Minho, Department of Engineering of the University of Liverpool and Department of Mechanical Engineering of the MIT. The main keywords for the project are rheology and computational fluid dynamics. During manufacturing and processing many materials in the textile and paper industries exhibit non-Newtonian

rheology, such as shear-thinning, normal-stress effects, viscoelasticity, thixotropy, etc. There is the need to be able to predict and understand the deformation and flow of such materials. In broad terms the aims of the group are:

Development of more robust and accurate numerical methods and techniques for the simulation of non-Newtonian flows. Acquire benchmark data to assess the numerical solutions.

Enhance physical understanding of flow phenomena involving non-Newtonian materials.

Task – Numerical investigations of fundamental non-Newtonian flows Research wase carried out with the following purposes: 1) Elastic instabilities in flows through expansions and

cross-slots – non-Newtonian viscoelastic models induce flow asymmetries in situations where the corresponding Newtonian flow is symmetric. Cross-slot devices, in particular, are employed in microfluidic applications, for example to uncoil and count DNA molecules.

2) Non-Newtonian flows in bifurcations – motivated by hemodynamical applications (genesis and location of atherosclerotic diseases). The size and intensity of vortices formed near bifurcating channels were quantified as a function of Reynolds and Deborah numbers.

3) Algorithms for computational rheology – robustness of present methods was enhanced by implementing the log-conformation formulation for the stress equations and different algorithms were tested in time-dependent viscoelastic flows.

Publications

The work developed by the Group of Fundamental Sciences has been published in the most diverse forms, being in Figure 1 a summary of the number and form of these publications in the last 6 years.

Tabela 1. Data concerning the publications, communications and advanced training of the Group of Fundamental Sciences.

Indicators 2005 2006 2007 2008 2009 2010 Total

Books - - - - 1 - 1

Papers in international journals 14 10 17 15 14 7 77

Papers in national journals 1 1 - - 3 - 5

International Scientific Meetings 30 9 14 13 14 23 103

National Scientific Meetings 9 6 - - 23 13 51

Organization of Conferences 1 - 1 2 4 3 11

PhD Thesis 2 2 1 2 1 2 10

MSc Thesis 2 1 - 6 7 9 25

Grants 1 1 1 8 6 7 24 Projects with financial support from the Fundação

para a Ciência e a Tecnologia

PTDC/CTM/64865/2006 Development of new electrode materials based in nanocomposite films for environmental applications, 2007-2011 (FCUL e UBI). PTDC/EME-MFE/70186/2006 “UNSTABLE- Instabilities in Viscoelastic Flows”, 2007-2010 (FEUP & UBI). PTDC/AAC-AMB/103112/2008 Electrochemical degradation of leachates from sanitary landfills, 2010-2013 (UBI, FCUL, UNL, UE). PTDC/QUI-QUI/100896/2008 Affinity Interactions between Cyanine Dyes and Biomolecules in Chromatographic Processes”, 2010-2012.

PTDC/EME-MFE/98558/2008 “Compressible Viscoelastic Flows”,. Jun. 2010 - (3 y) (UBI). PTDC/EME-MFE/113988/2009 “IProExt- Integrated System for the Automatic Design of Profile Extrusion Production Tools”, Jan. 2011 (3 y) (Univ. Minho & UBI). PTDC/EME-MFE/114322/2009 “EXTENSION- Extensional Flow of Complex Fluids in Microfluidic Devices”,, Jan. 2011 (3 y) (FEUP & UBI). PhD Grant, SFRH/BD/68357/2010 - Joana Mafalda Moura Malheiro, “Elastic and Inertial Instabilities in Laminar Flows with Curvature”, 2011.

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Laminar Newtonian flows in square curved ducts at moderate Reynolds number J. Malheiro1, P.J. Oliveira1, F.T. Pinho2

1Universidade da Beira Interior, 2Faculdade Engenharia Universidade Porto

Abstract The present numerical study is an introductory computer simulation work on the characteristics of incompressible fluid flow in curved ducts of square cross section. Here, the fluid is assumed Newtonian and the conditions of Bara et al [3], Mees et al [4] and Helin et al [7] were considered, in order to make comparison of results. Good agreement between the velocity profiles were found, especially for the lower Reynolds number (Re) considered. As Re was increased to 532 and 583, differences were observed at the end part of the curve. Those differences were higher for Re=583 and other solutions were presented to match the results of Bara et al [3].

Introduction Fluid flows in curved ducts can be found in many industrial and engineering applications, such as in most fluid transport systems within the chemical, food and manufacturing industries, in environmental engineering, in waste heat recovery systems, in air-conditioning, refrigeration and power production system ducts and in bio-engineering (e.g., human organs – arteries, lungs, catheter, etc.). Since the early XXth century this type of flow arose a particular interest in the scientific community. This interest comes from the centrifugal induced secondary flows first reported by Dean in 1927 that straight channels do not show. Although this secondary flows may have undesirable effects (e.g., increase in pressure drop; degradation of long chain molecules of polymeric fluids by the high shear stress), it can also be beneficial as it improves heat and mass transfer (e.g., in thermal homogeneity and membrane separation, respectively), enhance cross-sectional mixing (e.g., homogeneity of a mixture along the cross-section of the channel) and reduction in axial dispersion (e.g., diffusion of a solute in a flowing liquid). [1, 2]. The secondary flow in a curved channel, also known as Dean flow, is induced by unbalanced centrifugal forces, as consequence of a non-uniform axial velocity distribution, and results in a pressure gradient normal to the streamwise direction. This pressure gradient (the pressure is higher at the outer wall than at the inner, bottom and top walls, where there is slow moving fluid) generates a secondary flow from the outer to the side and inner walls and finally towards the centre of the channel which then feeds the outer wall region. Thus, the flow is characterized by two symmetrical vortices that occupy the entire cross-section of the channel and its magnitude is measured by the Dean number (Dn). The Dean number is defined by the ratio of the square root of the product of inertial and centrifugal forces to the viscous force [3]:

ReDn

Rc, where Re

Ua

is the Reynolds number

and R

Rca

is the curvature ratio [3]. U is the average

velocity at inlet, a is the side of the square cross section and R is the radius of curvature of the channel. However, as Re is increased, in the laminar regime, the flow becomes more complex and a second symmetrical pair of counter-rotating vortices appears near the outer wall [3]. Mees et al [4] showed that at Dn = 453 a third pair of counter-rotating vortices appears, Winters [5] presented multiple solutions within certain ranges of values of Re, and Soh [6] showed that the inlet conditions affect the flow downstream. More recently, Helin et al [7], following the same geometry of Bara et al [3], presented results of the development of the flow considering a viscoelastic fluid. Many works dealing with flows in curved channels have been published [1, 2], for different cross-sections, values of Re (or Dn), curvature ratios, fluid models, etc., using both numerical and experimental approaches, and thus showing how complex this kind of flow can be. However flows in curved channels of complex fluids are not yet completely understood, and even for Newtonian fluids the results obtained by different investigations are not always in agreement thus justifying the present contribution.

Governing Equations Here we consider three-dimensional, laminar, isothermal, steady flow of an incompressible Newtonian fluid. The governing equations, which describe the behaviour of the flow, are presented in general form:

i) Mass conservation: 0.u

ii) Momentum conservation:

tot

Dp

Dt t

u uu. u .τ

where u is the velocity vector (with u, v and w components for the x, y and z directions, respectively), ρ is the fluid density, t is the time, p the pressure and τtot the extra stress tensor.

iii) Constitutive equation:

2T u u D

which is Newton’s law for viscosity, where η is the

constant fluid viscosity and Tu is the transpose of the

velocity gradient tensor. Numerical Method The numerical solution of the governing equations is obtained by the Finite Volume Method, which maps the computational domain in cells (control volumes) and discretizes the equation in time and space, resulting in a

28

linearized set of algebraic equations solved by adequate conjugate gradient solvers and the SIMPLEC algorithm. The geometry is a three-dimensional curved channel with square cross-section. To generate the mesh the channel is divided into three blocks (Figure 1-a)):

i) Block I: a straight channel of width 1a and length 20Le a at the entrance;

ii) Block II: a connecting 180º curved channel, with internal radius 1 14.6R a and external radius

2 15.6R a (these dimensions are the same as those of Bara et al [3], Mees et al [4] and Helin et

al [7] 1 2

15.12

R RR

);

iii) Block III: and a straight channel at the exit, having the same dimensions as the inlet channel.

The origin of the Cartesian coordinates system (x, y, z) is at the bottom corner of the first block of the curved channel (Figure 1-b)). A non-uniform spaced mesh has been used and its geometrical characteristics are presented in Table 1. This table shows the number of cells in each block for each direction, the total number of control volumes (NCV) and the factor of compression/expansion (f) for each direction. The value of this factor defines the size of the smallest cell and is such that guarantees smooth transition between cell dimensions. Thus, when the mesh is uniform it takes the value of one, and when the mesh is non-uniform, as the case here, the compression factor in the x direction is about 4.8% in Block I and the expansion factor is about 5% in Block III. Table 1 – Geometrical characteristics of the computational mesh

Mesh

NX × NY × NZ x

f yf

zf

Block I 30 × 20 × 20 0.95212 1.00000 1.00000

Block II 161× 20 × 20 1.00000 1.00000 1.00000

Block III 30 × 20 × 20 1.05029 1.00000 1.00000

NCV 88400

A no-slip condition is applied at all walls (u = v = w = 0) and a uniform velocity profile is imposed at the inlet of the entrance channel. Its length is such as to guarantee that the flow is fully developed when entering the curved part of the channel. At the exit of the outlet channel a zero axial-gradient condition was imposed. The simulations were done using the entire domain of the channel, due to the possibility of occurrence of asymmetries in the flow. Results and Discussion The results are presented mainly for three different Re numbers: Re = 486, Re = 532 and Re = 583, which correspond to Dn = 125, Dn = 137 and Dn = 150, respectively. The same conditions from Bara et al [3], which were later considered by Mees et al [4] and Helin et al [7], were also assumed here. Figure 2 exhibits contour and vector plots of the distribution of dimensionless streamwise velocity and the secondary

Figure 1 – Geometrical characteristics of the channel (geometry not to scale). velocity field at the entry to the curve. At this position the maximum of the velocity is located at the centre of the channel, which corresponds approximately to a parabolic velocity profile along the symmetry plane of the cross-section. Theoretically this velocity for fully-developed flow in a straight square duct is 2.096 and numerically we obtained 1.978, 1.959 and 1.939 for Re = 486, Re = 532 and Re = 583 in the curved duct, respectively.

Figure 2 – Contours and vector plots of dimensionless axial and secondary velocity at the entry to the curved channel. At the beginning of the curve, the flow tends, in the first place, to run as in a straight channel due to its inertia until it finds the outer wall. As the fluid moves along the curve, the centrifugal force maintains the maximum velocity towards the outer wall as illustrated in Figure 3, which shows contours of axial velocity along the curve mid-plane (z=0.5) and also axial velocity contours and secondary velocity vector plots in the cross-section at 90º (middle of the curve), for different values of Re. This figure demonstrates that, at 90º, the secondary flow is already established and the two symmetrical counter-rotating vortices are clearly observed. Looking to the vector plots in Figure 3, and as shown previously [3,7] at this location of the channel there is still no sign of an additional pair of vortices, except for Re=583 which shows, near the outer wall and between the large vortices,

29

the early development of an additional pair of smaller vortices. This could probably be predicted with a refined mesh near the outer wall The development of the streamwise velocity profiles along the symmetry plane of the channel is plotted in Figure 4. In this figure the results are compared with those of Bara et al [3]. For Re= 486, at the beginning of the curve (20º), the velocity profile is already asymmetric and the maximum velocity is located near the outer wall due to the inertia of the incoming flow. At 40º, the maximum velocity has decreased and started to move back to the centre of the channel and the velocity near the inner wall increase, as a result of the redistribution of momentum induced by the secondary flow that is gradually setting in. At 60º the transfer of momentum continues and the velocity near the inner wall and centre slightly increase. However, at position between 80º and 100º the flow is already developed, and no change in velocity profile is verified until the end of the curve. Up to 80º, for Re=532 the flow develops in the same way as for Re=486. After 100º the velocity profile shows that the maximum velocity moves back toward the centre of the channel, which confirms the early development of the additional vortices near the outer wall, and the flow does not reach a fully developed regime as it progresses along the curve. For Re=583 the flow development is approximately the same up to 60º, but then the development of the additional pair of vortices occurs at an earlier position (80º), and downstream of 140º the maximum velocity peak is located near the centre of the channel. Once again, the curved channel length (a 180º curve that is L = πR ) is not sufficient for the flow to develop completely before exiting through the outlet channel. Now, comparing results with those obtained by Bara et al [3], it can be seen in Figure 4 that they are not completely in agreement. At Re=486 (Figure 4 a)) our results were practically the same as those of Bara et al [3]. This is also verified at Re=532 (Figure 4 b)) but only up to 140º. At 160º and 180º a slight difference is observed and a better agreement is obtained when our predictions use a somewhat higher Reynolds number of Re=556. At Re=583 the discrepancy between results becomes larger and is observed upstream of that for Re=532. At θ=100º and for higher angles there is a better match between our predictions and those of Bara et al [3] if the Reynolds number is increased to Re=600. Conclusions The purpose of this work was to verify the major characteristics of an incompressible Newtonian fluid flow in a curved duct of square cross section, already reported by many authors [1-7], as an introduction to a deeper investigation of this kind of flows in the future. Thus, the same conditions assumed by Bara et al [3] were also considered here. It was verified that at 90º only for the higher Re= of 580 signs of an additional pair of counter-rotating vortices appear near the outer wall.

a)

b)

c) Figure 3 – Counters of axial velocity in the central plane of the channel (left) and the cross-section (right top) and velocity vectors in the cross-section (right bottom) at position of 90º for: a) Re=486 (Dn=125), b) Re=532 (Dn=137) and c) Re=583 (Dn=150). In general, the evolution of velocity profiles in the channel is very similar for the different Re. At the beginning of the curved channel the maximum velocity is rapidly shifted towards the outer wall; further downstream the maximum velocity peak decreases and starts to move

30

back to the centre of the channel, because the secondary flow sets in and there is a tendency for the flow to recover a more fully profile shape. For Re=482 the flow is fully developed before the maximum velocity reaches the centre of the channel, and the flow is characterised by a secondary flow consisting of one pair of counter-rotating vortices. On the other hand, for Re=583 the maximum velocity (which was located near the wall at the initial stages of the curve) almost reaches the centre of the channel due to the appearance of an additional pair of vortices.

The velocity profiles at the central plane of the channel were compared with those presented by Bara et al [3]. Although good agreement was found for Re=480, the same was not verified for higher Re. At Re=532, the disparity between the results is small and is only observed at the end of the curve. However, for Re=580 the differences tend to increase and occur earlier in the flow. In order to match the results to those of Bara et al [3] it was necessary to use higher values of Re for the Re=532 and 583 cases of Bara et al [3].

a)

0

0.5

1

a

40 80 120 160 20020 60 100 140 180

b)

0

0.5

1

a

40 80 120 160 20020 60 100 140 180

c)

0

0.5

1

a

40 80 120 160 20020 60 100 140 180

Figure 4 – Comparison of the predicted velocity profiles at the central plane of the channel for: a) Re=486 (+); b) Re=532 (+) and 556 (); c) Re= 583 (+) and 600 (), against the results of Bara et al [3] (lines) for Re= 486 (a)), 532 (b)) and 583 (c)). References 1. Vashisth, S., Kumar, V., Nigam, K.D.P., Ind. Eng.

Chem. Res., 47, 3291, 2008. 2. Berger, S.A., Talbot, L., Yao, L.-S., Ann. Rev. Fluid

Mech, 15, 461, 1983. 3. Bara, B., Nandakumar, K., Masliyah, J.H., J. Fluid

Mech., 244, 339, 1992. 4. Mees, P.A.J., Nandakumar, K., Masliyah, J.H., J. Fluid

Mech., 314, 227, 1996. 5. Winters, K.H., J. Fluid Mech., 180, 343, 1987.

6. Soh, W.Y., J. Fluid Mech., 188, 337, 1988. 7. Helin, L., Thais, L., Mompean, G., J. Non-Newtonian

Fluid Mech, 156, 84, 2009.

Acknowledgements The authors acknowledge Fundação para a Ciência e Tecnologia for the financial support under the project PTDC/EME-MFE/70186/2006.

31

Influence of the technology of simple and double wool fabrics in the design and performance of garments

R. Miguel, S. Melo, M. Pereira, J. Lucas and M. Santos Silva Textile Department, Textile and Paper Materials R&D Unit, University of Beira Interior

Abstract This work aims to study the different behaviour of single and double fabric types when applied to the same garment. Through a comparative analysis, it is intended to evaluate and characterize the performance of two fabrics (one single and one double) in designing the same garment (jacket), namely aesthetic and functional fabric behaviours during wear. In this comparative process it is also intended to highlight the close links between technology and design of fabrics and garments, through the relationship of the technical characteristics of fabrics with the aesthetic and functional performances of fabrics and clothing. Introduction ICSID (International Council of Societies of Industrial Design) states that "Design is a creative activity whose aim is to establish the multi-faceted qualities of objects, processes, services and their systems in whole life cycle. Therefore, design is the central factor of innovative humanisation of technologies and the crucial factor to the economic and cultural exchange". For the designer Peter Dormer (1993), "the relationship between design and technology is not unilateral. The technological development does not determine what the manufacturer intends to produce, determines the ways that the designer creates". To Bürdek (2005), "the design ... is aggregated to the concepts of creativity … and of technical innovation and so generates an expectation of the design process to be a kind of cerebral act". This author reinforces the idea that creativity and technique are crucial in a design process. The design has been asserting itself, filling historical gaps, settles itself between four traditionally hardly-interacting knowledge systems: humanities, technology/engineering, art/creativity, economy and management (Figure 1). Its attitude in catalyzing contents and synthesizing their effects in terms of form, function, value and meaning for the final user represents an essential component and constitutes the object of a growing number of studies focalizing on the so-called “metaprojectual” phase of the design process (Celaschi et al., 2009). The clothing conception (and its components) is a special case of involvement design in the project of products. This peculiarity arises from the importance that clothing has for the physical and psychological human well-being, since we live in a constant relation with garments. The fabric, as raw material for clothing, has a huge relevance in aesthetic and functional components of clothing design project. Regarding the clothing, fabrics must answer primarily to two factors: the functional and aesthetic. It is essential to

the fabric to be functional in order to be able to meet the basic needs of protection and comfort. The aesthetic component of the fabric is related to the colour and harmony of colours in patterns, the weave and the relationship weave/ pattern, the drape or fluidity of the fabrics and the overall look that is still influenced by the raw materials and finish. The domain of these parameters by designers allows introducing the differentiation, leading to consumer satisfaction when they wear certain products. These two factors, functional and aesthetic, are critical in conception of a fabric design project aiming its success in response to market, embedded in a logic of constant demand by designers, as an integral part of the design process, creativity and innovation.

Figure 1: Design as mediator between knowledge systems (Celaschi e al., 2009) Double fabrics are those consisting of two warps and two wefts, creating a woven fabric composed of two juxtaposed simple fabrics. The production technology of double fabrics is used in conventional fabric weaving, depending on the weave and yarn densities, being used when it is intended to obtain heavier fabrics, while avoiding the increase of rigidity caused by increasing the yarn densities, thus keeping the flexibility at satisfactory levels. On the other hand, double fabrics, because they are made of two simple ones, allow a range of appearance and function between their two sides, in terms of colours, patterns and types of yarns, including raw materials, as shown in Figure 2. Generally, fabric drape determines the sensory comfort and aesthetics that fabrics give to garments. The more fluid or more armed shape, that is, with more volume, as

32

Figure 2: Wool/polyester double fabric produced at the Weaving Workshop of Textile Department of UBI the garment having a good drape, according to the aesthetic the designer intends for his garment, is related to the bending and shear rigidities of the fabric that makes the garment, including its ability of fabric to adapt to the three-dimensional shape of the garment (Miguel, 2000). In textile fashion design project there are quality parameters to be followed as a strategy for achieving the application performance which is expected for fabrics. Examples of quality parameters of fabrics on their performance in the comfort and drape during wear are: Fabric drape "Drape" (Drapemeter apparatus); Air permeability (Air Permeabilimeter aparatus); Thermal Resistance (Alambeta apparatus); Resistance to water vapour (Permtest apparatus); Fabric objective properties (mechanical) (FAST and Kawabata systems). Materials and Methods In the experimental methodology, two fabric and two garment projects were developed, which gave rise to so many prototypes aiming to evaluate and compare the aesthetic and functional behaviour of single and double fabrics during wear (Melo, 2010) . The development of the technical fabrics project started by defining the weight/m2 considering fashion trends and the intended application for the fabrics: Winter coats for ladies. In this definition and considering that both single and double fabrics must have the same weight/m2, it was also considered the compatibility between weight/m2, yarn count, weave, cover factor and fabric type - double and single. Thus, it was considered for both fabrics a weight/m2 of 340g/m2. From this definition and taking into account the equation for the theoretical calculation of weight/m2 of Miguel (2000):

M/m2 =((DB.100).((CLB+100)/100))/Nm+((DT.100). ((CLT+100)/100))/Nm

Where: M/m2 - weight per square meter of fabric in g/m2 DB – Warp yarn density in yarns/cm DT – Weft yarn density yarns/cm CLB – Warp fabric contraction in %

CLT – Weft fabric contraction in % Nm – Yarn count in metric system (Nm) as well as the use of siro-spun dyed yarn, having a 2/50 Nm count for the double fabric and, twisted to give a 4/50 Nm count, for use in the simple fabric, the warp and weft yarn densities for each fabric were calculated, considering an average warp and weft contraction of 7.5%, according to Escobet (1960). As the same yarn in the warp and weft was used, it was also considered, for calculations purposes, the same densities of warp and weft, being after increased in the fabric production the warp density, reducing the one on weft in the same proportion (Table 1). In the UBI workshops the project was materialized into two prototypes, a double and a simple fabric, with the same regular woollen finish, carried out at Fitecom SA. company. Table 1: Technical construction of simple and double fabrics

Simple fabric Double fabric Fabric composition 55% Polyester/45% Wool Fundamental weave Neutral 4 twill Derived weave Broken twill with oposition Fabric contraction 7.5% Weight/m2 340g/m2 Yarn count (Siro-spun) 4/50Nm 2/50Nm Warp density 21 yarns/cm 40 yarns/cm Weft density 18.6 yarns/cm 39 yarns/cm Average float 2 2 for each

simple fabric Weave coefficient 0.5 0.5 for each

simple fabric In order to evaluate the drape of single and double fabrics in their final applications and during wear, the development and prototyping of garments was analyzed starting from fabrics. After searching trends in www.syle.com and www.massimodutti.com sites and the definition of the concept, a pre-selection was done and the garment chosen for the implementation of the prototype was a short coat for Winter in a casual style. The choice of this typology was due to the fact that it is a propitious shape to highlight the fabric drape, having no lining and non-conventional reverses. The technical worksheet of prototypes to be produced was developed – two equal ladies’ coats, one for each fabric, single and double (Figure 3). The prototyping of the coats was made in the Clothing Workshop of the Textiles Department of UBI, having the type of fabric as the only differentiating variable between coats. Results and Discussion With this work very interesting results in terms of technology of fabrics and the interaction between technology and design were obtained. The results of laboratory tests, shown in Table 2, reveal, first, that the fabric parameters show quality levels that meet the standards required by international organizations such as the Woolmark Company.

33

Figure 3: Technical worksheet of coats prototypes For the group of properties related to comfort, the two fabrics have different behaviours. The double fabric is more permeable to air (472l/m/s) and water vapour (6.8%) and more insulating to heat (17.2 m2.K/W) than the simple fabric (84.7 l/m²/s, 7.5%, 10.4 m2.K/W). The double fabric has the same weight/m2 than the simple one at the expense of the increased thickness formed by the two overlapping simple fabrics, but also due to the use of thinner and more widely spaced yarns. For this reason, the spatial geometry of the double fabric is more porous as compared to the simple one, favouring the air and water vapour permeabilities. It is also because it has a greater thickness and the corresponding air content, that the double fabric is more heat insulating than simple fabric. Considering the weight/m2 of fabrics, the application of both is in winter clothing, the double fabric being the one that best meets the weather requirements, with the exception of being more uncomfortable than the simple fabric on windy days. Concerning the mechanical behaviour of fabrics, including the bending and shear rigidities, both fabrics show also differences in their behaviour. The double fabric has a smaller drape (48.3%) in the drapemeter than the simple fabric (33.9%). In the FAST system, the warp bending rigidity is equal for both fabrics (0.4 uN.m), while for the weft is higher in the simple fabric (0.6 uN.m) than double (0.3 uN.m). These results of the bending rigidity measured using FAST system and

drapemeter seem contradictory, but they represent a very interesting innovation in this study. The ability of fabrics to adapt to the three dimensions of the garment is higher in the double fabric than in simple one, according to the respective values of shear rigidity (20N/me 37N/m). Indeed, in the double fabric yarns are less compressed and thus have a greater freedom of movement, presenting therefore lower shear rigidity. Table 2 also shows the influence of the characteristics and properties of fabrics in the design of fabrics and garments made with them. The results are also very interesting. As it can be seen, all the technological fabrics parameters have some influence on design, either in surface appearance, either in the fabric drape and touch. The performance level of some parameters influence the use of fabrics, although in the cases studied it appears that fabrics are suitable for the manufacture of coats chosen. The study shows that the fabrics roughness, measured with a surface analysis test, has a direct relationship with the look and touch, conditioning the application. Indeed, the double fabric has a higher roughness (6.855) than the simple (3.642), since yarns are packed in the simple fabric. In the double, the yarn densities of the component fabrics are more open and the three-dimensional effect causes greater yarn positional freedom to floats, favouring increased irregularity of fabric surface and the gain of a textured look, so suitable to casual applications. In this perspective, the double fabric showed the best fit to the coat chosen, considering its casual cut. The relationship between the drape of the fabrics, their bending and shear rigidities and the aesthetic aspect of the drape of coats is very interesting to discuss. Figure 4a shows the shape of the drape of double fabric, i.e., in all directions at once. There is a regular shape with seven pleats less pronounced than on the simple fabric (Figure 4b) that shows a less regular contour with six pleats. These results indicate that the double fabric has a more fluid drape but with more volume. The volume is noticed by the drape value given by the drapemeter test and is due to the higher thickness (1.162 mm and 0.767 mm) and to the three-dimensional structure of the double fabric.

a b Figure 4: Fabric drape in drapemeter, a. double fabric and b. simple fabric The greater fluidity is noted by the increased number of pleats formed in drapemeter test and also by the lower bending rigidity given by the FAST system (0.3uN.m and

34

0.6uN.m). The lower shear rigidity of the double fabric contributes to uniformity and naturalness of fabric and coat drape. Figures 5 and 6 show the two coats in actual wear. Figure 5 shows the coat constructed with the double fabric, being easy to observe what was proved by the

technological parameters results, i.e., a more voluminous, natural and fluid drape than the in the coat built with the simple fabric shown in Figure 6. Similarly and even the aesthetic point of view, the double fabrics offer two sides, which may be distinct, to the designer's creativity

Table 2: Influence of characteristics and properties of fabrics in fashion design

Values

Characteristics and properties of fabric Simple Fabric

Double Fabric

Constraints and influence in fabrics and clothing

design

Air permeability (l/m2/s) 84.7 472.0 Application, comfort Water vapour permeability (Permetest method)

Coefficient of variation – CV% - (reference CV=5%)

7.5 6.8 Application, comfort

Thermal behaviour (Alambeta method)

Thermal resistance – r (m2.K/W)

10.4 17.2 Application, comfort

Fabric drape (Drapemeter method) (%) 33.9 48.3 Sensorial comfort, look Warp (C-1) 4.8 4.8Bending lenght

(mm) Weft (C-2) 5.7 4.4Warp (B-1) 0.4 0.4

Ben

ding

Bending rigidity (uN.m) Weft (B-2) 0.6 0.3

Sensorial comfort, drape, adaptation of garment to the 3rd dimension

Shear rigidity (G) (N/m) 37 20Sensorial comfort, drape, adaptation of garment to the 3rd dimension

Under 2g (T2) 0.767 1.162Under 100g (T100) 0.641 0.857

Det

erm

inat

ion

of (

FA

ST

) pa

ram

eter

s

Com

pre

ssio

n

Thi

ckne

ss (

mm

)

Surface thickness (ST) 0.126 0.305

Application, look, comfort – thermal behaviour

Surface properties evaluation Kawabata KES-FB4 system

Average roughness SMD

3.642 6.855 Application, look, touch

Figure 5: Coat made with double fabric

Figure 6: Coat made with simple fabric

Conclusions The purpose of this study was satisfied. Very interesting results in the comparative analysis of two samples with the same weight/m2, a single and another double, with regard to its aesthetic and technical performance in clothing were obtained. For application in casual Winter coats the double fabric showed better performance with the exception of the air permeability behaviour. References 1. Dormer, P., El diseño desde 1945, Ediciones Destino,

1993. 2. Burdek, B., História, Teoria e Prática do Design de

Produtos, Editora Edgard Blücher Ltda, São Paulo, 2005.

3. Celaschi, F., et al., Design culture: from Product to Process, Building a network to develop design processes in Latin countries, 2010.

4. Miguel, R., Modelização da influência das características estruturais nas propriedades condicionantes do comportamento ao uso dos tecidos de lã e mistos, Tese de Doutoramento, UBI, Covilhã, 2000.

5. Melo, S., Análise comparativa do design, do desempenho e da aplicação de tecidos simples e duplos, Dissertação de Mestrado em Design de Moda, UBI, Covilhã, 2010.

6. Escobet, V., Tecnologia del Tejido, Terrasa, 1961.

35

Influence of surface sizing with different binder systems on inkjet print quality S. Sousa 1, A.P.M. de Sousa 2, B.M. Reis 2, A. Ramos1

1Research Unit of Textile and Paper Materials, University of Beira Interior, 6201-001 Covilhã, Portugal 2RAIZ – Institute of Forest and Paper Research, Apartado 15, 3801-501 Eixo, Portugal

Abstract The aim of this study is to analyze the paper surface modifications carried out by surface sizing with formulations composed by different binder systems and evaluate the inkjet print quality of the produced papers. Cationic starch and polyvinyl alcohol had been used in order to improve the inkjet print quality. These binders originate papers with different structure and physical-chemical properties and therefore distinct print quality. Parameters such as line width, blur, raggedness, inter-color bleed, circularity and dot gain, gamut area and optical printing densities were measured. The results showed higher performance of the paper surface sized with only polyvinyl alcohol exhibiting better balance between color and line/dot properties. This paper sample presents lower air permeability, higher smoothness and non-polar surface. In opposition, the paper treated with starch gives higher raggedness, significant polar component and lowest gamut area.

Introduction Inkjet printing is a popular low-cost method producing high quality digital images. The inkjet print quality depends on the printer, inks nature and paper characteristics [1,2]. Recent developments in printer technology and printing inks lead to an increase in the requirements for paper performance. Most inkjet inks have low viscosity and low surface tension, which set high demands on paper porosity and absorbency characteristics. Different surface treatments can be carried out in order to improve print quality. The main types of surface treatments are: surface sizing, calendering and coating [2]. Surface sizing process consists of the application, under pressure, on both sides of the paper, of a formulation composed basically by binders, wetting or hydrophobizing agents and resins or polymers, with a typical dry solids content between 2-15% [3,4]. A conventional surface size dispersion is composed of dissolved starch and a suspended sizing agent which makes the paper surface hydrophobic in order to reduce the water absorption [5,6]. Other agents such as polyvinyl alcohol, sodium alginate, carboxymethyl cellulose, polyurethane, styrene acrylate copolymers, styrene maleic anhydride copolymers, among others, are also used [2,5,7-12]. The print quality evaluation is made with specific tests of a printed paper sample, involving image analysis for the quantification of various parameters such as blur, raggedness, inter-color bleed, circularity and dot gain and optical printing density.

The ideal paper for inkjet printing should absorb quickly the ink carrier liquid, whilst, at the same time, retains the coloured dye or pigment on the surface. Colorant retention on the sheet surface minimizes the blur, raggedness and inter-color bleed while maximizing the color densities [9,13]. Fewer studies have been published on open literature concerning surface sizing and their impact on inkjet print quality [7,8,12,14,15]. The present study reports the influence of various surface sizing formulations designed with different binders compositions on paper properties (structural and physical-chemical), and their relation to inkjet print quality parameters. Materials and Methods Materials: The 74.4 g/m2 base paper (B) used for surface sizing treatments was produced from bleached softwood and hardwood mix kraft pulp and was internal sized. The binders used in surface sizing were cationic starch (S) and a fully hydrolyzed polyvinyl alcohol (PVA). The test liquids employed on contact angle measurements for surface energy determination, were distilled water, methylene iodide (Aldrich, 99% purity) and ethylene glycol (Merck, > 99.5% purity).

Sizing preparation and application: Four formulations were produced, with blends of the cationic starch suspension and PVA solution in different proportions - S/PVA: 100/0; 80/20; 50/50 and 0/100. All formulations were prepared with 11.8% solids content, excepting S/PVA: 0/100 formulation which was 8% solids content. The surface sizing was applied with a laboratory reverse roll coater (Mathis Type RRC-BW) at room temperature, only on one side of the base paper. The coater operating conditions were maintained constant: pressing power between applicator roll and transport roll at 3.5 bar, the nip between dip roll and applicator roll was -125 m and rolls speed was 20 m/min. All sized sheets were dried on an IR drier for 2 min reaching a final temperature of 100ºC. The papers were conditioned at 23ºC and 50% relative humidity during 24 hours, before physical characterization and printing.

Surface sized papers characterization: The surface sizing pick up was determined according to ISO 536:1995 standard. Bendtsen air permeability and Bekk smoothness of the paper sheets were determined according to ISO 5636-3:1992 and T 479 om-91 standards, respectively. The surface free energy and corresponding dispersive and polar components of the samples were obtained by

36

contact angle measurements performed with the Dataphysics equipment OCAH 200 by means of sessile drop method using three test liquids. The surface free energy was determined using the geometric mean according to Owens, Wendt, Rabel and Kaelble approach [16].

Print evaluation: The surface sized papers were printed on a HP Deskjet F370 printer with a particular test chart, in order to evaluate the line and dot print quality parameters and color reproduction capacity. The width, raggedness and blur of horizontal black line were measured, whereas inter-color bleed was calculated from black over yellow and yellow over black line sections. From a matrix of black dots, gain and circularity were also measured. The parameters related with the line and dot quality analysis were performed on a QEA personal image analysis system (PIAS II). The software for parameters analysis is based on ISO/IEC-13660:2001. Color measurements were carried out in an Avamouse Spectrocam handheld reflection spectrometer under the following conditions: D65 illuminant, observer 2º, instrument geometry 45º/0º and Status I as density spectral response. The gamut area was calculated as the area of hexagon (a*,b*), where a* and b* are the L*a*b* CIE coordinates obtained for cyan, magenta, yellow, red, green and blue. The optical printing density of the black was calculated by the difference between optical density of the printed area and the paper. Results and Discussion Paper properties are presented in Table 1. The sizing pick up range from 1.7 to 3.5 g/m2, depending on the formulations viscosity and solids content. It is also possible to observe that all surface sized papers have similar and low air permeability, indicating that the papers have a closed structure. This low air permeability is provided by the base paper. Table 1 – Values of sizing pick up, Bendtsen air permeability and Bekk smoothness of paper samples

Paper Sizing pick

up (g/m2)

Bendtsen air

permeability

(ml/min)

Bekk

smoothness

(s)

B -- 337 23.80 S 3.5 247 5.75

S/PVA:80/20 1.8 291 16.17 S/PVA:50/50 1.8 290 16.00

PVA 1.7 289 20.30 Concerning Bekk smoothness, all surface sized papers presented lower smoothness, relating to base paper. A possible explanation for this result is the re-humidifying of the paper during the sizing process and the subsequent drying with lower tension, resulting in greater fibers freedom reorganization. The paper surface sized with starch showed less smoothness. According to Maurer and Keraney [17], drying conditions for starch binder in a

coating must be carefully controlled in order to avoid non-uniform porosity. The lower effectiveness of the starch in terms of film formation, compared with PVA, may explain the lower smoothness of the paper surface sized with starch against PVA.

From a physical-chemical point of view, the papers sized with different formulations showed somewhat similar values for surface free energy but with distinct characteristics of polarity, as can be seen in Fig. 1. The base paper is practically non-polar due to internal sizing that make it hydrophobic. The paper surface sized with starch presents a significant polar component. Starch formulation, although composed by a mixture of several additives, mainly contains starch. This is a hydrophilic polymer that binds to cellulose fibers through hydrogen bonds [17], providing a noteworthy polarity.

0

5

10

15

20

25

30

35

40

B S S/PVA:80/20 S/PVA:50/50 PVA

Su

rfa

ce e

nerg

y (

mN

/m)

Total Dispersive Polar

Figure 1 – Total surface free energy and its dispersive and polar components for the paper samples

The addition of 20% PVA practically does not change the physical chemistry of the paper surface when compared with the starch treatment. Only at a higher level of PVA addition (50%) there has a significant decrease of the polar component, maintaining however a similar paper surface free energy. Paper treated only with PVA, exhibit a polar component close to zero. Despite the PVA polymer being hydrophilic [18], the paper surface sized with this polymer has a hydrophobic nature. Schuman et al. [18] found that the PVA fully hydrolyzed, exhibited lower moisture absorption when compared with other grades, being considered more water resistant than a partially hydrolyzed PVA. The same author explains that this trend is due probably to the larger number of hydrogen bonds between the hydroxyl groups in PVA fully hydrolyzed, making them less accessible to the water molecules [18]. The PVA used in the present work is fully hydrolyzed and the possible establishment of hydrogen bonds within polymer chains may also explain the non-polar character of the paper surface treated only with PVA.

The diagram of Figure 2 shows the performance of the different papers concerning to line and dot print quality parameters. The analysis of these parameters is quite difficult, since there are no clear trends. The assessment

37

of the parameters separately shows that the paper treated with starch presents highest blur, i.e., poorer sharpness. Concerning raggedness, a measure of the contour irregularity, it appears that all formulations improve the line contour. This parameter depends of the paper’s ability to spread the ink from its initial position, due to capillarity phenomena. The paper surface sized only with PVA, exhibit in general lower line width in relation to the papers treated with formulations containing starch. With regard to inter-color bleed, a comprehensive analysis of the results shows that base paper presents the highest value, and consequently, the poorest performance. The surface sizing improves the inter-color bleed, especially when using only PVA. Dot circularity values are fairly similar for the different papers in analysis. Dot gain increases with all treatments; however the paper surface sized with only PVA shows the better performance.

Figure 2 – Diagram of the line and dot print quality parameters. Performance worsens from chart center. (Dot_cir: dot circularity; L_Rag: raggedness and ICB: inter-color bleed)

In order to evaluate the color reproduction performance of the produced papers, optical printing density of the black and gamut area data are presented in Figure 3. As can be seen, all formulations have a positive effect in color reproduction. The lowest value of gamut area was observed for the paper treated with starch. Increasing PVA content in the formulation enhances the gamut area.

Concerning to optical printing density of the black, no clear trends was found. However, paper treated with only PVA show slightly higher value. The good film-forming nature of PVA contributes to achieve excellent performance on color reproduction. The PVA film prevents the deep ink absorption, keeping the dye/pigment at the surface, contributing to the higher gamut area and optical printing density.

7000

7400

7800

8200

8600

B S S/PVA:80/20 S/PVA:50/50 PVA

Ga

mu

t a

rea

1,0

1,1

1,2

1,3

1,4

Op

tica

l p

rin

tin

g d

en

sity

Gamut area PD-Bk

Figure 3 – Gamut area and optical printing density of the black for the paper samples. The paper surface sized with starch presents poor color reproduction properties and weak line and dot quality when compared to the others. These poor results may be related to the higher surface roughness and simultaneously higher polarity that contribute to ink spreading. Starch and PVA blends generates intermediate properties between starch and only PVA formulations, closer to the results obtained with starch or PVA depending on the properties considered. Conclusions In the present work, the paper surface was modified by application of different formulations. These were composed by blends of starch/PVA and the two binders isolated in order to evaluate the performance of these treated papers on inkjet print quality. The surface treatments produced papers with similar surface free energy but different polarity. There are no great variations in air permeability and roughness. The paper sized with PVA exhibit lower Bendtsen air permeability, higher Bekk smoothness and a non-polar surface. The existence of competing variables that determine the color reproduction and the line and dot printing parameters were clearly shown in the current study. High hydrophilicity and smoothness originates lower gamut area, resulting, probably, in the higher absorption and/or spreading of the inks. A higher performance was obtained when the surface sizing was carried out with only PVA. These papers exhibit a better balance between color capacity reproduction and line and dot print quality.

References 1. Xu, R., Fleming, P.D., and A. Pekarovicova, J. Imag.

Sci. Technol., 49(6), 660, 2005. 2. Fardim, P., TAPPI J., 1(7), 2002. 3. Heikkilä, L., Tommeras, A., Engels, T., and Knudsen,

E., Pigment Coating and Surface Sizing of Paper, In Gullichesen J. and Paulapuro H. (eds.), Papermaking Science and Technology, Book 11, Chap 20, TAPPI PRESS, Finland, 289, 2000.

4. Cho, B.-U., and Garnier, G., TAPPI J., 83(2), 2000.

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5. C., Andersson, and L., Jarnstrom, Distribution of starch and hydrophobic sizing agents, Proc. 5th International Paper and Coating Chemistry Symposium, Montreal, Canada, 2003.

6. Anderson, J., Surface sizing, In Brander J. and Thorn I. (eds.), Surface application of paper chemicals, Blackie Academic & Professional, London, UK, 138, 1997.

7. Koskela, J.P., and Hormi, O.E.O., Appita J., 56(4), 296, 2003.

8. Moutinho, I.M.T., Ferreira, P.J.T., and Figueiredo, M.L., Ind. Eng. Chem. Res., 46, 6183, 2007.

9. Boylan, J.B., TAPPI J., 80(1), 68, 1997. 10. Gunning, J.R., and Hagemeyer, R.W., Coating,

Converting, and Specialty Processes, In M. Kouris, (ed.), Pulp and Paper Manufacture, Vol 8, Chap I, TAPPI/CPPA, Atlanta, 3, 2000.

11. Garrett, P.D., and Lee, K.I., TAPPI J., 81(4), 198, 1998.

12. Batten Jr, G.L., Tappi J., 78(1), 142, 1995. 13. Ryu, R.Y., Gilbert, R.D., and Khan, S.A., TAPPI

J., 82(11), 128, 1999. 14. Saraiva, M.S., Gamelas, J.A.F., de Sousa, A.P.M.,

Reis, B.M., Amaral, J.L., and Ferreira, P.J., Materials, 3, 201, 2010.

15. Sousa, S., de Sousa, A.P.M., Koskela, J.P., Vaz, A., and Ramos, A., Appita J., 63(4), 300, 2010.

16. Owens, D.K., and Wendt, R.C., J. Appl. Polymer Sci., 13(8), 1741, 1969.

17. Maurer, H.W., and Kearney, R.L., Starch, 50, 396, 1998.

18. Schuman, T., Wikström, M., and Rigdahl, M., Nord. Pulp Paper Res. J., 18(1), 81, 2003.

39

Filmes de nanocompósitos: sua utilização na Fotoelectrodegradação do Corante AO7

T. Frade 1, A. Videira1, A. Gomes1, M. I. da Silva Pereira1, O. Monteiro2, L. Círiaco3, A. Lopes3 1C.C.M.M., Departamento de Química e Bioquímica, FCUL, Campo Grande, 1749-016 Lisboa, Portugal

2C.Q.B, Departamento de Química e Bioquímica, FCUL, Campo Grande, 1749-016 Lisboa, Portugal 3 UMTP e Departamento de Química, Universidade da Beira Interior, 6201-001 Covilhã, Portugal

Abstract Zn-TiO2 and Zn-TiO2/Ag2S nanocomposite films were prepared by pulse-reverse current electrodeposition, on titanium substrates, using an acidic zinc sulphate solution with TiO2 and TiO2/Ag2S nanoparticles in suspension. The SEM results show that different morphologies can be obtained depending on the particle nature incorporated into the metal matrix. After the electrodeposition process, the Zn-TiO2 nanocomposite films have been heated in air at 450 ºC for 6h. The XRD analysis of the deposits points to the metal matrix conversion from Zn to ZnO. The heat treated Zn-TiO2 films were used for the first time on the photoelectrochemical degradation of the AO7 dye. The degradation tests were performed at 1.0 V vs Ag/AgCl, under white light irradiation, in 0.035 M Na2SO4 solution with 5 ppm AO7, for 2 h. UV-Vis spectroscopy showed that the AO7 was efficiently degraded, with 40 % of color removal, after a 2 h period. Sumário Filmes de nanocompósitos de Zn-TiO2 e Zn-TiO2/Ag2S foram preparados por electrodeposição galvanostática pulsada, em substratos de titânio, usando uma solução de sulfato de zinco acidificada, com nanopartículas de TiO2 e de TiO2/Ag2S em suspensão. Os resultados de SEM mostraram que é possível obter diferentes morfologias de nanocompósitos de matriz metálica de Zn dependendo do tipo de partículas incorporadas na matriz metálica. Após o processo de electrodeposição, os filmes de nanocompósitos de Zn-TiO2 foram sujeitos a um tratamento térmico ao ar a 450 ºC durante 6h. As análises de XRD revelaram que houve uma conversão da matriz de Zn para ZnO. Os filmes de nanocompósitos de Zn-TiO2 tratados termicamente foram usados, pela primeira vez, na fotoelectrodegradação do corante AO7. Os ensaios de degradação foram realizados a 1.0 V vs Ag/AgCl, sob irradiação de luz branca, numa solução electrolítica de 0.035 M Na2SO4 e 5 ppm de corante AO7, durante 2 h. Análises por espectroscopia de UV-Vis mostraram que o corante foi eficientemente degradado, com uma percentagem de remoção de cor de 40 %, ao fim de 2 h. Introdução Presentemente os corantes utilizados na indústria têxtil têm exigido especial atenção devido à sua persistência no meio hídrico, após o tratamento dos efluentes, provocando problemas ambientais à escala mundial [1].

Existem vários métodos que permitem a remoção de cor e carga orgânica dos efluentes, mas muitos têm a desvantagem de serem de elevado custo, o que impossibilita a sua aplicação em larga escala na indústria têxtil [2]. A fotoelectrocatálise tem-se mostrado eficiente, económica e “amiga” do ambiente no tratamento de efluentes. Este método baseia-se na formação de pares electrões/lacunas, foto-gerados por irradiação de um semicondutor do tipo-n, que irão reagir com a água para formar radicais hidroxilo que serão os responsáveis pela degradação das moléculas dos corantes [3]. A aplicação, através de um circuito externo, de uma densidade de corrente ou de um potencial anódico constante ao fotoânodo irá permitir a foto-injecção de electrões que serão continuamente extraídos do fotoânodo, melhorando a eficiência do processo [4]. Os filmes de nanocompósitos de matriz metálica têm se mostrado promissores tanto como fotocatalisadores como fotoelectrocatalisadores para a degradação de poluentes devido às propriedades fotocatalíticas das nanopartículas incorporadas na matriz metálica. A sua preparação por electrodeposição galvanostática pulsada envolve baixos custos e permite uma grande versatilidade na preparação destes materiais, mediante o controlo dos parâmetros de deposição [5]. Neste trabalho estudaram-se filmes nanocompósitos, de matriz metálica de Zn, com nanopartículas de TiO2 e TiO2/Ag2S incorporadas. Avaliou-se a actividade fotoelectrocatalítica dos filmes contendo partículas de TiO2 bem como a sua aplicação na degradação do corante AO7, muito utilizado na indústia têxtil e papeleira. Parte Experimental Preparação dos filmes de nanocompósitos de Zn-TiO2 e Zn-TiO2/Ag2S Os nanocompósitos de Zn-TiO2 e Zn-TiO2/Ag2S foram preparados a partir de uma solução aquosa acidificada a pH 4 composta por 0.1 mol.dm-3 ZnSO4.7H2O (Sigma-Aldrich, 99 %), 0.2 mol.dm-3 MgSO4.7H2O (Sigma-Aldrich, ≥ 99 %), 0.15 mol.dm-3 H3BO3 (Panreac, 99.8 %) e 10 g.dm-3 de partículas de TiO2 (Aeroxide® P25) ou TiO2/Ag2S sintetizadas no nosso laboratório [6]. A electrodeposição decorreu sob agitação, fluxo de azoto e à temperatura ambiente.

Usou-se uma célula de vidro de dois compartimentos, e uma placa de Zn como eléctrodo secundário e um eléctrodo comercial de Ag/AgCl como referência. Foram utilizados, como eléctrodos de trabalho discos e placas de

40

Ti com áreas entre 0.8 e 1.5 cm2 (Goodfellow Corporation) Estes foram sujeitos a um pré-tratamento antes das electrodeposições. Os filmes de nanocompósitos foram preparados por electrodeposição galvanostática pulsada, aplicando as condições apresentadas na Tabela 1.

Table 1 – Valores do perfil eléctrico aplicado na

electrodeposição dos filmes de nanocompósitos. Tipo Ic

/ mA Ia

/ mA tc

/ ms ta

/ ms tdep total

/ min. Zn-TiO2 -15 15 16 8 100

Zn-TiO2/Ag2S -94.5 0 4 20 100 As electrodeposições foram realizadas usando um Potenciostato/Galvanostato Autolab PGSTAT12, com aquisição automática de dados por software GPES 4.9. Os nanocompósitos de Zn-TiO2 foram posteriormente aquecido ao ar durante 6h a 450 ºC, usando uma velocidade de aquecimento de 1 ºC/min. Caracterização dos filmes A caracterização estrutural dos filmes de nanocompósitos foi realizada por Difracção de raios-X (XRD), num Philips Analytical PW 3050/60 X’Pert PRO equipado com um detecto X’Celerator e com aquisição automática de dados, usando uma radiação monocromática de CuKα como feixe incidente. Os difractogramas foram obtidos por varrimento contínuo num intervalo de 2θ de 20 a 80 º, com um passo 2θ de 0.02 º e a uma velocidade de varrimento de 10 s/passo. A caracterização morfológica e elementar dos filmes foi realizada por Microscopia Electrónica de Varrimento acoplada a Espectroscopia de Dispersão de Energias (SEM/EDS) num FEG-SEM JEOL 7001F, com um feixe de electrões de 25 kV de potência.

Estudos fotoelectroquímicos e ensaios de fotoelectrodegradação Os estudos fotoelectroquímicos e os ensaios de fotoelectrodegradação foram realizados apenas para os nanocompósitos de Zn-TiO2 após a conversão da matriz metálica de Zn para ZnO. Registaram-se fotovoltamogramas na presença e ausência do corante AO7 (Sigma-Adrich), a λ=365 nm. O intervalo de potencial estudado foi de -0.15 a 1.20 V vs Ag/AgCl, a velocidade de varrimento de 2 mV.s-1 e a frequência de irradiação de 0.1 Hz. Utilizou-se como electrólito 0.035 M Na2SO4 +5 ppm de corante AO7. Os ensaios de fotoelectrodegradação do corante AO7 foram realizados potenciostaticamente a 1.0 V vs Ag/AgCl, sob irradiação de luz branca durante 2h, sob

agitação, à temperatura ambiente. O volume de solução foi 100 mL.

O processo de fotoelectrodegradação foi acompanhado por Espectroscopia de UV-Vis, num intervalo de 200 a 700 nm através de um espectrofotómetro Jasco V-560, com aquisição automática de dados, utilizando células de quartzo de 1 cm de percurso óptico. Resultados e Discussão Na Figura 1 estão representadas imagens de SEM de filmes de nanocompósitos de Zn-TiO2 (Fig. 1a) e Zn-TiO2/Ag2S (Fig. 1b), sendo as morfologias observadas muito distintas. Os nanocompósitos de Zn-TiO2 (Fig. 1a), apresentam a formação de estruturas hexagonais de dimensões variáveis, correspondentes à matriz metálica de Zn, sendo também visíveis alguns aglomerados que correspondem às nanopartículas de TiO2. No caso dos nanocompósitos de Zn-TiO2/Ag2S é difícil diferenciar a matriz metálica de Zn das nanopartículas. Este resultado é devido à elevada redução do tamanho de grão do Zn promovido pela presença das nanopartículas de TiO2/Ag2S.

Figura 1 – Imagens de SEM de filmes de nanocompósitos

de Zn-TiO2 (a) e Zn-TiO2/Ag2S (b) (ampliação de 5000x).

Zn TiO2

a)

b)

41

Na Tabela 2 apresentam-se os valores de distância interplanar (d), intensidade relativa (I) e planos de difracção correspondentes aos picos de difracção dos nanocompósitos de Zn-TiO2 antes e depois de sujeitos a um tratamento térmico de modo a modificar a matriz metálica de Zn para ZnO. Todas as reflexões dos nanocompósitos de Zn-TiO2 antes do tratamento térmico correspondem à fase cristalina do Zn hexagonal [7]. Após o aquecimento, a matriz metálica foi transformada com sucesso na estrutura cristalina de ZnO hexagonal [8]. Table 2 – Identificação das fases constituintes dos nanocompósitos de Zn-TiO2 antes e após o tratamento térmico.

O sucesso da conversão da matriz poderá ser atribuído à presença das partículas de TiO2 incorporadas na matriz metálica. Estudos realizados anteriormente, comprovaram que a presença de nanopartículas incorporadas numa matriz metálica promovem a diminuição do tamanho de cristalite [9], que por sua vez, permitirá a conversão da matriz de Zn em ZnO bem sucedida [10]. Segundo Lin et al [11], a presença das partículas de TiO2 afecta o crescimento do tamanho de grão da matriz metálica, impedindo o aumento do tamanho de grão durante o processo de recristalização por acção de calor.

Na Figura 2 mostram-se os fotovoltamogramas registados para os nanocompósitos de ZnO-TiO2 na ausência e na presença de 5 ppm de corante AO7, sob irradiação alternada.

Verifica-se que os fotovoltamogramas são semelhantes, no entanto, o valor da intensidade da fotocorrente é menor na presença do corante. Tipicamente, semicondutores do tipo-n, como o ZnO e o TiO2 originam fotocorrentes anódicas elevadas, que diminuem na presença de corantes [12]. Esta diminuição é devida à absorção da luz pelo próprio corante [13].

Figura 2 – Fotovoltamogramas obtidos para os nanocompósitos de ZnO-TiO2, no intervalo de potencial -0.15 a 1.20 V vs Ag/AgCl, em 0.035 M de Na2SO4, na ausência e na presença de 5 ppm de corante AO7. Velocidade de varrimento de 2 mV.s-1 e frequência de irradiação de 0.1 Hz. A Figura 3 mostra a evolução dos espectros de UV-Vis das soluções resultantes da fotoelectrodegradação do corante AO7. Como se pode observar, as bandas características do corante que se encontram a 485, 310 e 228 nm, sofrem alterações de amplitude ao longo do tempo de degradação. A banda de absorção a 485 nm que corresponde à ligação azo (-N=N-) presente no corante, sofre uma diminuição considerável com o tempo. Essa diminuição está associada à quebra da ligação azo, que leva à perda de coloração da solução. Observa-se o aumento das bandas 310 e 228 nm, que estão relacionadas com a formação de intermediários com anéis naftaleno e benzeno, respectivamente. Outros autores já obtiveram resultados semelhantes usando filmes mesoporosos de TiO2 [14].

Figura 3 – Evolução dos espectros de UV-Vis com o tempo

de irradiação para uma solução inicial de 5 ppm de AO7 em 0.035 M de Na2SO4, para um potencial aplicado de 1.0 V vs Ag/AgCl e sob irradiação de luz branca.

Zn-TiO2 após deposição Zn-TiO2 após o aquecimento

d / Å I / % (hkl) d / Å I / % (hkl)

2.4682 54.52 Zn (002) 2.8097 29.01 ZnO (100)

2.3034 26.71 Zn (100) 2.6007 21.03 ZnO (002)

2.0880 100.00 Zn (101) 2.4712 46.32 ZnO (101)

1.6861 15.82 Zn (102) 1.9087 8.52 ZnO (102)

1.3405 15.10 Zn (103) 1.6241 12.26 ZnO (110)

1.3313 10.80 Zn (110) 1.4754 10.58 ZnO (103)

1.1726 11.60 Zn (112) 1.3577 4.21 ZnO (201)

1.1234 8.00 Zn (201) - - -

200 300 400 500 600 7000.0

0.2

0.4

0.6

0.8

Ab

s

λλλλ / nm

0 min 30 min 60 min 90 min 120 min

42

A partir do valor de absorvância da banda a 485 nm foram calculadas as concentrações das amostras de AO7 ao longo do tempo, a partir da lei de Lambert-Beer, de modo a calcular a percentagem de remoção de cor do corante, em solução. Verificou-se que ao fim de 2 h de ensaio, a percentagem de remoção de cor é de aproximadamente 40 %, indicando que a fotoelectrodegradação do corante AO7 foi bem sucedida usando este tipo de material de eléctrodo. Estudos idênticos usando os filmes nanocompósitos Zn-TiO2/Ag2S encontram-se neste momento a decorrer no nosso laboratório.

Conclusões Mediante a incorporação de diferentes tipos de nanopartículas, foi possível obter morfologias diferentes para os filmes de nanocompósitos de matriz metálica de zinco.

A análise de DRX dos nanocompósitos de Zn-TiO2, após tratamento térmico, confirma a conversão da matriz metálica de Zn para ZnO.

Estes materiais revelaram-se fotoânodos eficientes para a degradação do corante AO7, tendo sido obtida uma remoção de cor de 40 % ao fim de 2 h. Referências 1. Oliveira, L. C. A.; Gonçalves, M.; Oliveira, D. Q. L.;

Guerreiro, M. C.; Guilherme, L. R. G.; Dallago, R. M.; J. Hazard. Mater., 141, 344, 2007.

2. Kunz, A.; Zamora-Peralta, P.; Moraes, S. G.; Durán, N.; Química Nova, 25, 78, 2002.

3. Rauf, M. A.; Ashraf, S. S.; Chem. Eng. J., 151, 10, 2009.

4. Martínez-Huitle, C. A.; Brillas, E.; Appl. Catalys. B: Environ., 87, 105, 2009.

5. Conway, B.; Vayenas, C.; White, R.; Gamboa-Adelco, M.; Modern Aspect of Electrochemistry, Vol. 38, Klumer Academic/Plenum Publishers, New York, 2005.

6. Neves, M. C.; Nogueira, J. M. F.; Trindade, T.; Mendonça, M. H.; Pereira, M. I.; Monteiro, O. C.; J. Photochem. Photobio. A: Chem., 204, 168, 2009.

7. JCPDS-ICDD International Center for Diffraction Data, Powder Diffraction File Alphabetical Index, Swathmore, PA, File 4-0831, 1988.

8. JCPDS-ICDD International Center for Diffraction Data, Powder Diffraction File Alphabetical Index, Swarthmore, PA, File 36-1451, 1988.

9. Frade, T.; Bouzón, V.; Gomes, A.; Silva Pereira, M. I. da; Surf. Coat. Technol., 204, 3592, 2010.

10. Deguchi, T.; Imai, K.; Iwasaki, M.; Tada, H.; Ito, S.; J. Electrochem. Soc., 147, 2263, 2000.

11. Lin, C. S.; Lee, C. Y.; Chang, C. F.; Chang, C. H.; Surf. Coat. Technol., 200, 3690, 2006.

12. Carneiro, P. A.; Osugi, M. E.; Sene, J. J.; Anderson, M. A.; Zanoni, M. V. B.; Electrochim. Acta, 49, 3807, 2004.

13. Bard, A. J.; Faulkner, L. R.; Electrochemical Methods, Fundamentals and Applications, vol. 4, Wiley, New York, 1970.

14. Li, J.; Wang, J.; Huang, L.; Lu, G.; Photochem. Photobiol. Sci., 9, 39, 2010.

Agradecimentos Os autores agradecem ao financiamento da Fundação para a Ciência e Tecnologia (Portugal), através do projecto de investigação PTDC/CTM/64856/2006. Também agradecem ao Doutor Killian Lobato pela ajuda nos estudos fotoelectroquímicos.

43

Antioxidant activity and bioactive compounds of methanolic extracts of some

Portuguese shrubs species Â. Luís 1, F. Domingues 1,2, A. P. Duarte 1,3

1Health Sciences Research Centre, 2Department of Chemistry, 3Faculty of Health Sciences University of Beira Interior

Abstract The Portuguese forest area is around 3.3 million hectares which represents about 38% of the territory. This leads to the production of large quantities of forest residues composed by several different shrubs species and tree branches. Those plants can be used as raw material for achieving high value chemicals, like bioactive compounds. Several constituents of plant extracts have been shown to have antioxidant activity, such as ascorbic acid, tocopherol, b-carotene, flavonoids, tannins, phenolics, and anthocyanins. The purpose of this work was to determine the phenolic, flavonoid and alkaloid contents of the methanolic, extracts of some shrub species, and then try to correlate it with antioxidant activity of same extracts. It was concluded that the antioxidant activity of extracts is directly related to their phenolics amount.

Introduction The Portuguese forest area is around 3.3 million hectares which represents about 38% of the territory. This leads to the production of large quantities of forest residues composed by several different shrubs species and tree branches. Examples of shrubs that grow spontaneously in Portuguese forests are Pterospartum tridentatum, Juniperus communis, Rubus ulmifolius, Cytisus multiflorus, Crataegus monogyna and Erica arborea. Those plants can be used as raw material for achieving high value chemicals, like bioactive compounds [1]. Pterospartum tridentatum is a Leguminosae belonging to the subfamily Papilionoideae that grows spontaneously in Portugal where it is known as Carqueja or Carqueija. The flowers are used in popular medicine for the treatment of throat irritation conditions and in herbal mixtures for diabetes. As far as we know, no phytochemical, pharmacological or toxicological studies have been reported for this species but quinolizidinic alkaloids and isoflavonoids are characteristic secondary metabolites of Leguminoseae species and their pharmacotoxicological properties are known for a long time [2]. Juniperus communis or common juniper is a coniferous shrub distributed throughout the Arctic and temperate zone of the northern hemisphere. Its dried blueish-black cones, known as “juniper berries”, are said to stimulate the appetite and are used as a flavouring agent for culinary purposes and in the preparation of gin spirits. They have also been used for various medicinal purposes, including as an abortifacient, antiseptic, contraceptive, diuretic, and as a remedy for urinary tract infections, chest complaints, diabetes, rheumatism and backache. The

smoke from burnt juniper branches has been used as a fumigant to prevent the spread of infections. More interestingly, juniper has been reported as a traditional cure for chest troubles such as bronchitis and for tuberculosis [3]. Rubus species (family Rosaceae) have been used traditionally for therapeutic purposes. Leaves and young shoots of Rubus ulmifolius are used in folk medicine for their anti-inflammatory, anti-odontalgic and gastrointestinal spasmolytic properties; crushed young shoots are applied to wounds, infected insect bites and pimples. It has also been reported that crude methanolic extracts of closely related species of Rubus ulmifolius exhibit antimicrobial properties on bacteria and fungi [4]. Cytisus spp. is used as diuretic, hypnotic and sedative, anti-diabetic and also as hepatoprotective [1]. Crataegus monogyna has long been used as a folk medicine due its sedative actions, protective effects against arrhythmias, and increase of coronary vessel flow. Activities of the extracts on skin microcirculation disturbances have also been studied. Previous chemical studies on Crataegus monogyna resulted in isolation of know flavonoids and phenolic acids [5]. Erica multiflora often used by hyperlipidaemic subjects as an alternative therapeutical tool to treat hyperlipidaemia, was also used in folk medicine as a diuretic and antiseptic agent. The phytochemical study of this plant was showed that the tannins, proanthocyanidols and flavonoids represent major compounds of its flowers [6]. Oxidation is essential to many organisms for the production of energy to fuel biological processes. However, reactive oxygen species are often over-produced under pathological conditions, resulting in oxidative stress. An over-production of various forms of activated oxygen species, such as free-radical and non-free-radical species, is involved in the onset of many diseases such as cancer, cardiovascular diseases, rheumatoid arthritis, and atherosclerosis, as well as in degenerative processes associated with aging. In order to reduce damage to the human body, synthetic antioxidants are used for industrial processing at the present time. However, the presence of unwanted side effects is almost unavoidable, and those most commonly observed have been suspected of being responsible for liver damage and carcinogenesis. Thus, it is essential to develop natural antioxidants so that they can protect the human body from free radicals and retard the progress of many chronic diseases. Several constituents of plant extracts have been shown to have antioxidant activity, such as ascorbic acid, tocopherol, b-carotene, flavonoids, tannins, phenolics, and anthocyanins [7].

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No single chemical component is responsible for the medicinal properties of plant-based drugs, and their synergic action or bioenhacement is due to the presence of other chemical substances in the plant material. Therefore, the determination of the total amount of different classes of components is essential for the standardization of the plants [8]. Alkaloids are low molecular weight nitrogen-containing substances with characteristic toxicity and pharmacological activity. These properties, which have traditionally been exploited by humans for hunting, execution and warfare, have also been used for the treatment of disease [9]. The purpose of this work was to determine the phenolic, flavonoid and alkaloid contents of the methanolic, extracts of the species mentioned above, and then try to correlate it with antioxidant activity of same extracts. The Folin-Ciocalteu’s method was used for the determination of total phenols, a colorimetric method with aluminum chloride was used in the determination of total flavonoids and Dragendorff’s reagent method was used to alkaloid estimation. The method of DPPH (2,2-diphenyl-1-picryl-hidrazil) was used to assess the antioxidant activity of extracts. Materials and Methods Plant material Aerial parts (stems, leaves, flowers and fruits) of the shrubs (Pterospartum tridentatum, Juniperus communis, Rubus ulmifolius, Cytisus multiflorus, Crataegus monogyna and Erica arborea) were collected in Serra da Estrela. Plant materials were dried at 35 ºC in a ventilated oven during 48 hours and reduced to coarse powder (< 2 mm) using a laboratory cutting mill. A voucher specimen of all species of shrubs has been deposited in the Biology Laboratory of Health Sciences Research Centre, University of Beira Interior. Extraction process Methanolic extracts were obtained with Shoxlet apparatus until the solvent became colorless, using 100 g of raw material and 1000 mL of solvent. The extract solutions were filtered under vacuum using a crucible of porosity 2 and then distilled under vacuum to remove the solvents to a final volume of 100 mL. Then, 5 mL of each extract was diluted in 45 mL of methanol. Aliquots (5 mL) of the extracts were removed for subsequent evaporation to dryness for the calculation of extraction yield. Total phenolic compounds determination The phenols were determined by Folin-Ciocalteu’s colorimetric method. The methanolic solutions of each extract (50 μL) or gallic acid (standard phenolic compound) were mixed with 450 μL of distilled water and then 2.5 mL of Folin-Ciocalteu’s reagent 0.2 N (diluted with distilled water) was added. The mixtures were allowed to stand for 5 minutes, and then 2 mL of aqueous Na2CO3 (75 g/L) was added. After incubation of these reaction mixtures (90 minutes / 30 C) the total phenols

were determined by colorimetry at 765 nm. The standard curve was prepared using 500, 400, 350, 325, 300, 250, 225, 200, 150, 125, 100 and 50 mg/L solutions of gallic acid in methanol (y=0.0009x; R2=0.9875). Total phenol values were expressed as gallic acid equivalents (mg/g of dry mass), which is a common reference compound for phenolic compounds [10,11]. Flavonoids determination Aluminum chloride colorimetric method was used for flavonoids determination according to Pourmorad, F. et al, [11] . Each extract (500 μL) in methanol was separately mixed with 1.5 mL of methanol, 0.1 mL of 10 % aluminum chloride, 0.1 mL of 1 M potassium acetate and 2.8 mL of distilled water. This solution remained at room temperature for 30 minutes; the absorbance of the reaction mixture was measured at 415 nm using a spectrophotometer. The calibration curve was constructed by preparing eight quercetin solutions at concentrations ranging from 12.5 to 200 μg/mL in methanol (y=0.0071x; R2=0.9979). Total flavonoid values were expressed as quercetin equivalents (mg/g of dry mass), which is a common reference compound for flavonoids [11]. Alkaloids estimation The alkaloids estimation was performed by spectrophotometric method of Dragendorff’s reagent as it was described by Sreevidya, N. et al, [8]. Briefly, 10 mL amount of each crude extract was centrifuged over 10 minutes (3000 rpm) to remove residual suspended particles and then 5 mL of the supernatant were mixed with 1 mL of HCl 0.1 N, 2.5 mL of Dragendorff’s reagent was added to the previous mixture, and after precipitation the precipitate was centrifuged over 5 minutes (3000 rpm). The precipitate was further washed with 2.5 mL of ethanol. The filtrate was discarded and the residue was then treated with 2.5 mL of disodium sulfide solution (1% w/v). The brownish black precipitate formed was then centrifuged (5 minutes, 3000 rpm). This residue was dissolved in 2 mL of concentrated nitric acid, with warming if necessary; this solution was diluted to 10 mL in a standard flask with distilled water and 1 mL was then pipetted out and mixed with 5 mL of thiourea solution (3% w/v). The absorbance of this solution was measured at 435 nm against a blank containing 1 mL of concentrated nitric acid and 2.5 mL of thiourea solution (3% w/v). The standard curve was prepared using 750, 500, 400, 250, 200, 150 and 100 mg/L solutions of pilocarpine nitrate in HCl 0.1N (y=0.0012x-0.1044; R2=0.9851). Alkaloid contents were expressed as pilocarpine nitrate equivalents (mg/g of dry mass) [8]. Evaluation of antioxidant activity: DPPH scavenging assay The antioxidant activity of the extracts and standards (gallic acid, quercetin, rutin and trolox) was determined by the radical scavenging activity method using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) as it was

45

described by Scherer, R. et al, [12]. Briefly, about 0.1 mL aliquots of methanolic solutions of the extracts or standards at different concentrations were added to 3.9 mL of a DPPH methanolic solution. Three DPPH solutions were tested, 0.2000, 0.1242 and 0.0800 mM, prepared by dissolving 39.4, 24.5 and 15.8 mg in 500 mL of methanol, respectively. These concentrations were selected due to the linearity range of DPPH solutions: above 0.2 mM the concentration is very high, and below 0.5 mM the color is very weak having a limited range of absorbance reading. The blank sample consisted in a solution of 0.1 mL of methanol mixed with 3.9 mL of DPPH. After a 90 min incubation period at room temperature in the dark, the absorbance was measured at 517 nm. The radical scavenging activity was calculated as follows: I % = [(Abs0 - Abs1) / Abs0] × 100, where Abs0 was the absorbance of the blank and Abs1 was the absorbance in the presence of the test sample at different concentrations. The IC50 (concentration providing 50% inhibition of DPPH radicals) was calculated graphically using a calibration curve in the linear range by plotting the extract concentration vs the corresponding scavenging effect. The antioxidant activity was expressed as the antioxidant activity index (AAI), calculated as follows: AAI = (final concentration of DPPH - µg.mL-1)/(IC50-µg.mL-1) [12]. Thus, the AAI was calculated considering the mass of DPPH and the mass of the tested sample in the reaction, resulting in a constant for each sample, independent of the concentration of DPPH and sample used. In this work it was considered that shrub extracts showed poor antioxidant activity when AAI < 0.5, moderate antioxidant activity when AAI between 0.5 and 1.0, strong antioxidant activity when AAI between 1.0 and 2.0, and very strong when AAI > 2.0, according to Scherer, R. et al, (2009). Assays were carried out in triplicate and all the samples and standard solutions, as well as the DPPH solutions, were prepared daily [12].

Results and Discussion As can be seen by the graphic of the Figure 1, generally, the extracts from stems and leaves have higher amount of phenolic compounds. By contrast, extracts of flowers and fruits have more flavonoids. The extract of stems of Crataegus monogyna is the one that have the greatest concentration of total phenols. Simultaneously this extract had the greatest antioxidant activity, i.e., this extract is the one that required the lowest concentration to promote 50% of inhibition (IC50) and higher value of AAI, which classifies the activity of this extract as being a very strong antioxidant. All Erica arborea extracts have very strong antioxidant activity, which indicates no significant differences in the composition of total phenols and flavonoids in different parts of this shrub. In other way, Cratageus monogyna fruits have moderate antioxidant activity with correspondent value for IC50, which is the biggest and lower AAI. It can be observed that the content of phenolics in the extracts correlates with their antiradical activity. Those results suggest that the phenolic compounds contribute significantly to the antioxidant capacity of the investigated species. The extract from stems of Cytisus multiflorus is the richest in alkaloids. These species are known to possess alkaloids, namely spartein, with anti-arrhythmic properties [13]. Of all the studied species, Juniperus communis is the poorest in alkaloids.

Figure 1 – Phenolic compounds (mg gallic acid equivalents / g dry mass) and flavonoids (mg quercetin / g dry mass).

050

100150200250300350400

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46

Conclusions All studied extracts showed significant antioxidant activity. This activity is directly related to the presence of phenolic compounds. It is necessary to identify the compounds responsible for this activity and carry out studies of cytotoxicity and genotoxicity for the pure compounds. It should be noted the presence of alkaloids in all extracts, and the extracts of Cytisus multiflorus are the richest in these compounds.

References 1. Luís, Â., Domingues, F., Gil, C., Daurte, A.P., Journal

of Medicinal Plants Research, 3, 886, 2009; 2. Vitor, R., Mota-Filipe, H., Teixeira, G., Borges, C.,

Rodrigues, A., Teixeira, A., Paulo, A., Journal of Ethnopharmacology, 93, 363, 2004;

3. Gordien, A., Gray, A., Franzblau, S., Seidel, V., Journal of Ethnopharmacology, 126, 500, 2009;

4. Sisti, M., Santi, M., Fraternale, D., Ninfali, P., Scoccianti, V., Brandi, G., LWT, 41, 946, 2008;

5. García, M., Sáenz, M., Ahumada, M., Cert, A., Journal of Chromatography A, 767, 340, 1997;

6. Harnafi, H., Bouanani, N., Aziz, M., Caid, H., Ghalim, N., Amrani, S., Journal of Ethnopharmacology, 109, 156, 2007;

7. Xu, W., Zhang, F., Luo, Y, Ma, L., Kou, X., Huang, K., Carbohydrate Research, 344, 217, 2009;

8. Sreevidya, N., Mehrotra, S. , Journal of AOAC International, 86, 1124, 2003;

9. De Luca, V., Pierre, B., Trend in Plant Science, 5, 168, 2000;

10. Tawaha, K., Alali, F., Gharaibeh, M., Mohamed, M., El-Elimat, T., Food Chemistry, 104, 1372, 2007;

11. Pourmorad, F., Hosseinimehr, S., Shahabimajd, N., African Journal of Biotechnology, 5, 1142, 2006;

12. Scherer, R., Godoy, H., Food Chemistry, 112, 654, 2009;

13. Raja, S., Ahamed, N., Kumar, V., Mukherjee, K., Bandyopadhyay, A., Mukherjee, P., Journal of Ethnopharmacology, 109, 41, 2007.

Acknowledgements Â. Luís acknowledges a fellowship from Fundação Para a Ciência e a Tecnologia (Reference: SFRH / BD / 65238 / 2009).

Table 1 – Alkaloids and antioxidant properties of methanolic extracts studied.

Specie Plant part Alkaloids (Pilocarpine nitrate

Equivalents mg/g of dry mass)* IC50 (mg/L)* AAI*

Antioxidant

Activity

Pterospartum tridentatum Stems and leaves 11.83 ± 0.64 69.65 ± 11.92 0.69 ± 0.06 Moderate

Flowers 12.12 ± 0.10 26.09 ± 1.31 1.69 ± 0.06 Strong

Juniperus communis Stems 8.03 ± 0.28 12.39 ± 0.31 3.44 ± 0.07 Very strong Leaves 3.13 ± 0.29 16.78 ± 0.58 2.37 ± 0.07 Very strong Fruits 4.90 ± 0.02 81.11 ± 6.87 0.63 ± 0.05 Moderate

Rubus ulmofolius

Stems 18.99 ± 0.99 14.70 ± 1.22 2.71 ± 0.20 Very strong Leaves 11.97 ± 0.31 17.26 ± 1.17 2.45 ± 0.35 Very strong Flowers 10.92 ± 1.82 10.96 ± 0.54 3.21 ± 0.16 Very strong Fruits 5.26 ± 0.11 78.80 ± 5.87 0.66 ± 0.04 Moderate

Cytisus multiflorus

Stems 78.55 ± 0.45 64.90 ± 3.16 0.77 ± 0.05 Moderate Leaves 39.39 ± 0.56 35.14 ± 1.39 1.40 ± 0.05 Strong Flowers 22.78 ± 0.11 71.52 ± 8.76 0.70 ± 0.09 Moderate Fruits 37.83 ± 0.67 76.96 ± 8.56 0.71 ± 0.07 Moderate

Crataegus monogyna

Stems 13.47 ± 0.49 8.54 ± 0.20 5.26 ± 0.13 Very strong Leaves 13.63 ± 0.52 16.46 ± 0.33 2.74 ± 0.05 Very strong Flowers 9.49 ± 0.23 13.64 ± 0.19 3.29 ± 0.05 Very strong Fruits 10.31 ± 0.21 86.47 ± 12.52 0.62 ± 0.06 Moderate

Erica arborea Stems 17.05 ± 1.37 14.60 ± 1.48 3.10 ± 0.28 Very strong Leaves 6.69 ± 1.07 10.87 ± 0.11 3.08 ± 0.04 Very strong Flowers 12.42 ± 0.48 16.14 ± 0.71 2.07 ± 0.10 Very strong

Trolox - - 8.38 ± 0.13 6.62 ± 0.10 Very strong Gallic acid - - 2.23 ± 0.02 22.77 ± 0.25 Very strong

Rutin - - 10.66 ± 0.39 4.90 ± 0.21 Very strong Quercetin - - 4.32 ± 0.39 12.17 ± 1.71 Very strong

* Results in terms of mean ± standard deviation

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Anodic oxidation of the dye Acid Orange 7 at different anode materials D. Santos, L. Ciríaco, M.J. Pacheco, A. Lopes

UMTP and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal

Abstract The electrodegradation of a model compound, Acid Orange 7 (AO7), was performed with 3 different anodes: a commercial boron-doped diamond (BDD) and two SnO2-Sb2O4 electrodes prepared in our laboratory, with and without platinization of the titanium substrate, followed by alternate electrodepositions of antimony and tin, with further calcination, to form the oxides, and to obtain the Ti/Pt/SnO2-Sb2O4 and Ti/SnO2-Sb2O4 anodes. The structural, morphologic and chemical characterization of the electrodes was done by X-ray diffraction, scanning electron microscopy and spectroscopy of dispersion energy, respectively. The anodes were tested in the degradation of AO7 in the presence of a salt, Na2SO4, at two different current densities, 10 and 20 mA cm-2, during 6 hours for BDD anode and 24 hours for the SnO2-Sb2O4 anodes. The degradation tests were followed by UV-Vis absorption spectrophotometry and chemical oxygen demand (COD) and total organic carbon (TOC) determinations. The best results for the removal of COD and TOC were obtained with the BDD electrode, followed by the Ti/SnO2-Sb2O4 anode. The platinization of the substrate did not improve the COD removal but it increased the service-life of the electrode. Introduction The treatment of industrial effluents arising from dye houses is, nowadays, of important concern because of the environmental problems they can cause. Dyes are harmful substances, since most of them are toxic and cancinogenic for live organisms, affecting many ecosystems. Some of those dyes are not biodegradable, or give origin to non biodegradable metabolites. So, more efficient treatment processes must be achieved to avoid the anthropogenic contamination of waters. In the last decades, electrochemical oxidation has shown to be a good alternative process to eliminate pollutants. Several anode materials have been studied in the last years, like noble metals, metallic oxides, namely doped SnO2, and boron doped diamond; these later materials have conduced to effective degradation/ mineralization of several pollutants [1-4]. From all the studies performed, it is evident that the choice of the anode material is highly important, since it must possess some important properties, namely: stability in the experimental conditions of the electrodegradation process, even at high anodic current intensity; high potential for the oxygen evolution reaction; long lifetime; and the preparation process should not be too expensive. In this work the electrodegradation of AO7 was performed with 3 different anodes: a commercial BDD anode and two composite electrodes, Ti/Pt/SnO2-Sb2O4

and Ti/SnO2-Sb2O4, prepared in our laboratory, with and without platinization of titanium substrate. The platinization of the substrate intends to improve the service-life of the anode by avoiding a TiO2 inter-layer formation [5-7].

Materials and Methods Preparation of the SnO2-Sb2O4 electrodes To prepare the Ti/Pt/SnO2-Sb2O4 electrode, the titanium substrate was first submitted to a pre-treatment [4]. After that, the electrodeposition of platinum was performed at 65 ºC, in an H2PtCl6 acid solution, applying a current density of 250 mA cm-2 [7], and using two plates of platinum with 10 cm2 as anodes and, as cathode, the titanium plate, with 10 cm2 (both sides) geometric area, placed between the anodes. The electrodeposition of tin was performed, at 35 ºC, in a acid solution of SnCl2, applying a current density of 10 mA cm-2, and using two plates of platinum as anodes and the plate of platinized titanium as cathode, between them. The antimony electrodeposition was also performed at 35 ºC, in an acid solution of Sb2Cl3, applying a current density of 10 mA cm-2, and using an experimental set-up similar to that used in the electrodeposition of tin. Alternate electrodepositions of Sn and Sb were performed four times. The titanium substrate with the electrodeposited metals was annealed at 550ºC, during 6 hours, to obtain the respective oxides. In the preparation of the Ti/SnO2-Sb2O4 electrode, the platinization step was omitted. Structural, morphologic and chemical characterization of the anodes The prepared electrodes were characterized by the following techniques:

X-Ray diffraction (XRD) Scanning electron microscopy (SEM) Energy dispersive spectroscopy (EDS)

Monitorization methods for the degradation assays The following analyses were performed with the samples collected during the electrodegradation assays:

UV-Vis absorption spectrophotometry COD determinations TOC determinations

Experimental conditions for the degradation assays Figure 1 presents the experimental set-up used in the degradation assays. The assays were run at 10 and 20 mA/cm2 applied current densities. 200 mL of solution were used, containing AO7 with a concentration of 100 ppm and the supporting electrolyte, Na2SO4, 0,035 M.

48

Figure 1 – Experimental set-up for the degradation assays. 1- Power supply; 2 - Anode – Ti/Pt/SnO2-Sb2O4 (10 cm2), Ti/SnO2-Sb2O4 (10 cm2) or BDD (10 cm2); 3 - Cathode – stainless steel (10 cm2); 4 - Magnetic stirrer; 5 – Stirring plate Results and Discussion In Figure 2 the X-Ray diffractograms for the prepared anode materials allowed the identification of two phases: SnO2 and Sb2O4. The micrographies, presented in figure 3, show a similar aspect for both materials, i.e., with and without platinization, meaning that, in principle, the platinization shouldn’t interfere with the degradation assays’ performance.

Figure 2. X-Ray diffractogram of the prepared materials.

a) b)

Figure 3. Micrographies of (a)Ti/Pt/SnO2-Sb2O4 and (b) Ti/SnO2-Sb2O4

The micro-analysis of the electrodes’ surface by EDS shows similar compositions for both materials, with the following atomic percentages:

• Ti/Pt/SnO2-Sb2O4 - 74% O; 9% Sn; 17% Sb. • Ti/SnO2-Sb2O4 - 75% O; 9% Sn; 16% Sb.

The COD results for the samples collected during the anodic oxidation assays are presented in the upper part of figure 4. The highest COD removal rate was obtained with the BDD anode.

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Figure 4. COD, TOC and Abs(482 nm) results for the samples collected during the AO7 degradation with the different anode materials, at the two applied current densities (10, 20 mA cm-2). Regarding the two composite materials, the best results were attained with the material prepared without platinization of the substrate. These conclusions are also valid for TOC results (figure 4, middle graphic), being the discrepancy between TOC removals obtained with

49

Ti/Pt/SnO2-Sb2O4 and Ti/SnO2-Sb2O4 anodes even higher than those for COD. Regarding the absorbance removals, at 482 nm (lower part of figure 4), the same tendency is observed, but with smaller differences for the different anode materials. The behaviour observed for the material with the platinized substrate may be due to the cauliflower aspect of the surface, with high porosity, that allows the contact between the solution and the platinized layer. Platinum is known to show a high tendency towards adsorption that leads preferentially to conversion rather than combustion reactions. In fact, this is the behaviour shown in the electrodegradation of AO7 at Ti/Pt/SnO2-Sb2O4, where very high absorbance removal, medium COD decay and very low TOC elimination was observed. Conclusions Composite materials were prepared and used in the electrodegradation of the dye Acid Orange 7 and the following conclusions were obtained: - The Ti/Pt/SnO2-Sb2O4 and Ti/SnO2-Sb2O4 composites present similar morphology, with high porosity. - Ti/Pt/SnO2-Sb2O4 is the anode that shows lower COD and TOC removals, probably due to the porosity of the oxides deposit and the adsorption tendency presented by platinum, conducting to a lower mineralization of AO7. - Ti/SnO2-Sb2O4 anode present higher COD and TOC removals than the platinized anode, but the service-live was significantly improved with the platinization, that avoid the TiO2 inter-layer formation, with high resistivity. - BDD anode is the one that presents the best results for the absorbance, COD and TOC removals, after 6 hours assays as can be seen in Table 1.

Tabela 1. Results for the COD, TOC and Absorbance removals for the electrodegradation assays of AO7 run at 20 mA cm-2.

Removal at 6 h / % Anode material COD TOC Abs (482 nm)

Ti/Pt/SnO2-Sb2O4 27 9 97

Ti/SnO2-Sb2O4 53 25 98

BDD 96 76 100 References 1. Kotz, R., Stucki, S., and Carcer, B., J. App.

Electrochem., 21, 14, 1991. 2. Cossu, R., Polcaro, A.M., Lavagnolo, M.C., Mascia,

M, Palmas, S., and Renoldi, F., Environ. Sci. Technol., 32, 3570, 1998.

3. Stucki, S., Kötz, R., Carcer, B., and Suter, W., J. App. Electrochem., 21, 99, 1991.

4. Electrochemistry for the Environment, Ed: Ch. Comninellis and G. Chen, Springer New York Dordrecht Heidelberg London, 2010.

5. Montilla, F., Morallón, E., De Battisti, A., and Vázquez, J.L., J. Phys. Chem. B, 108, 5036, 2004.

6. Río, A.I., Molina, J., Bonastre, J., and Cases, F., J. Haz.. Mater., 172, 187, 2009.

7. Andrade, L.S., Rocha-Filho, R.C., Bocchi, N., and Biaggio, S.R., Quim. Nova, 27, 866, 2004.

Acknowledgements The financial support of FCT is gratefully acknowledged: - PTDC/CTM/64856/2006 - BI Grant awarded to D. Santos

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Intelligent Clothing for Health Care

I. G. Trindade 1,2, M. Pereira1,2, R. Salvado1,2, J. Lucas1,2, N. Garcia1,3, J. Santos Silva 1, 2 and R. Miguel1,2 1Unidade R&D de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, Covilhã 6201-001, Portugal 2Departamento de Ciência e Tecnologia Têxteis, Universidade da Beira Interior, Covilhã 6201-001, Portugal 3Departamento de Informática, Universidade da Beira Interior, Covilhã 6201-001, Portugal Abstract In this article, two prototypes of intelligent clothing are presented. One consists of a sleeve to monitor skeleton muscle activity by surface electromyography (SEMG), the other consists of a T-shirt, to monitor heart-beat rate (HBR). Both, the sleeve and the T-shirt, are made of elastic knitting (lycra). An innovative approach was used, consisting in the application of plain-weave fabrics, to integrate textile electrodes for the physiological sensing, that are sewed in a particular manner to the inner-face of the elastic knits of the clothing. Introduction Since the year 2000, European Union considered Research and Development (R&D) in intelligent clothing or smart garments of great strategic importance, mainly for cuts in Health Care costs but also for improvement of human beings quality of life. Several European Projects, involving prestigious Industrials and Research Centers have been funded [1-7]. The main achievements consist of T-shirts to monitor the cardiac complex wave (P QRS T wave) in the 5-lead configuration, knitted by the seamless technique and the intarsia method, where the electrodes are stainless steel (SS) based electrically conductive yarns [8]. The T-shirts also integrate textile sensors to monitor pulmonary and abdominal ventilation and body movement. Muscle activity monitoring has also been demonstrated. Nowadays, many spin-offs from Universities have been formed, e.g. in Italy [9], Finland [10], United Kingdom [11] and Portugal [12]. Nevertheless, for reasons that are beyond the scope of this article, intelligent garments are not yet commonly used in Health Care. Furthermore, the research and development in the area have not stopped to increase. It is expected that in the near future, intelligent garments will replace the traditional ones; the new generations have great proximity to electronics and they may prefer and adapt well to garments that are also functional. Examples are garments that integrate devices to accumulate electrical energy to recharge computers and mobile phones [13] or fashionable garments that use shape memory materials [14]. To acquire know-how in these emerging technologies is important. Furthermore, some issues remain to be solved; signal fidelity with the person walking, standing or sleeping; signal isolation; clothing architecture to have it as little intrusive as possible and appealing to use and maintain.

This article describes an innovative concept for the integration of textile electrodes in garments. Two prototypes were developed, a sleeve to monitor muscle activity of forearms by SEMG measurements and a T-shirt to monitor cardiac beat rate. Both prototypes were conceived to be used with a commercial wireless portable unit and their evaluation was made with volunteers standing still and in motion. Comparisons with signals obtained with standard electrodes are presented and discussed. Materials and Methods The plain-weave fabrics that are used as support for the textile electrodes are made of 45% wool / 55% polyester. Small size plain-weave fabric strips (about 10cm x 10cm) had sewed rectangular shape embroidery electrodes, using a stitching machine and SS/cotton yarn supplied by Dyntex Korea. The yarn consisted of two cotton plies twisted around a 30m diameter SS filament. The mono-filament is non-corrosive and has good resistance to break. Two stitching passages were used in the embroidery pattern making, to assure that if a thread was broken in the process, the electrode could be finished, by continuing the stitching from the point it was interrupted [15]. Moreover, the two layers provide the electrode with higher robustness and lower electrical resistance. Polyester thread was used for tacking. In the sleeve, one fabric strip integrated two electrodes, with an area each of 1cm2 and a distance between the center of each electrode defined by ye-e= distance along the length of the muscle fibers and xe-e= distance along the width of the muscle, of 2.5cm and 1cm, respectively. In the T-shirt, three electrodes with similar area and xe-e = 2cm were used. The plain-weave fabrics suffer very little dimensional variation, under applied stress, keeping the distance between electrodes nearly unchanged. The fabric strips with the embroidery electrodes were immersed in a 70% concentration sulfuric acid aqueous solution bath at a temperature of 40 0C for 15 minutes. After the chemical treatment, the cotton fibers were completely removed from the electrodes, exposing the SS filaments. Consequently, the face of the textile electrodes making contact with the skin is electrically conductive while the outer-face (polyester side) is not. The plain-weave strips were then sewed to the elastic knits of lycra that shape the clothing. The elastic knitting provides applied pressure to the electrodes against the skin, for good electrical contact.

51

For the signal acquisition and recording, a commercial wireless portable unit (BioPlux) was connected to the textile electrodes, through snap fasteners and interconnects of twisted cotton/SS threads. A view of the textile electrodes and portable unit are shown in Fig. 1. In Fig. 1c) are also visible standard electrodes tapped to a volunteer human forearm.

The electrical signals captured by either standard or textile electrodes, are conducted through twisted threads and two BioPlux cables to an electronic proximity module. In the module, the signals are filtered and amplified by a factor of 1000 and connected through one cable to the portable unit, which transmits the signals as data at a rate of 1 kHz, via wireless, to a PC within a spatial radius of about 30 meters. To evaluate the performance of the prototypes, the signals obtained with them were compared with those obtained in similar conditions, including electrodes positioning, but using standard bipolar Ag/AgCl electrodes. The muscle activity monitoring experiments through SEMG signals were performed with a nine to ten event sequence, consisting of the tightening of the hand of the

forearm muscle being exercised, during a short period of time, followed by hand opening for a similar period of time. A view of the sleeve for the monitoring of skeleton muscle activity of the forearms is shown in Fig. 2. As previously indicated, the sleeve integrates two snap fasteners to allow the connection of the wireless portable unit cables. In SEMG measurements, a third electrode, the electrical ground, must be connected to a part of the skin that does not cover muscle (in Fig. 2, tapped to bone of the wrist). A view of the T-shirt for the monitoring of the HBR is shown in Fig. 3. The lycra T-shirt is covered by a stylish cotton cover (Fig.3a). The portable unit is held inside a pocket (Fig3b and c). In the HBR measurement, the BioPlux uses three electrodes and cables, connecting the electronic proximity module of the BioPlux to the textile

interconnects through snap fasteners (Fig 3d). The experiments consisted of a volunteer wearing the T-shirt, either standing or walking. Results and Discussion A comparison between the SEMG signals obtained with the sleeve (textile electrodes) and standard electrodes is shown in Fig. 4. The signal amplitude and shape are very similar in both experiments, but the noise level, observed in the baseline signal (corresponding approximately to no muscle activity) is higher in the experiments with textile electrodes than in those with standard ones. Furthermore, it was observed that in some regions of the

Fig. 1: a) and b), embroidery textile electrodes in plain-weave stripes, before and after cotton removal, respectively; c) BioPlux portable unit connected to standard electrodes on human arm.

Fig. 2: Photo of sleeve worn by a volunteer during forearm muscle exercising. A standard electrode is used for the electrical ground.

Fig. 3: a) Front-view of T-shirt as exposed at Portugal Tecnológico 2010; b) back-side view of interior of T-shirt showing BioPlux wireless portable unit; c) same as b) but with portable unit inside pocket; d) detail of snap fasteners connections BioPlux to textile twisted yarns interconnects.

52

room, the noise level in the experiments with the sleeve, could be very high (not shown), indicating the need to integrate a scheme for shielding signal interference of electromagnetic and electrostatic nature. In Fig. 5 are compared the cardiac signals obtained with the volunteer standing and using either standard electrodes or wearing the T-shirt. Because the T-shirt was made with a lycra knitting that applied low pressure and exhibited low resilient properties, two issues occurred. Firstly, the contact between the textile electrodes and the skin was low, causing too high noise level, so the experiments had to be performed with the volunteer applying pressure with his hand over the heart region (Fig.5b). Secondly, an attempt was made to not use the volunteer hand over the electrodes, by narrowing the T-shirt by approximately 2.5cm on each side. As shown in Fig. 5, while the pressure applied by hand was enough to provide a signal comparable to that obtained with standard electrodes in terms of amplitude and noise level, the same was not obtained by narrowing the T-shirt by 5cm (Fig.5c). While the signal obtained is good enough to obtain the HBR, the noise level is considerably higher than in the other two experiments. In addition, after some time, the noise level became too high. After the T-shirt was taken out by the volunteer, strong deformation in the T-shirt was present. The experiments with the volunteer walking exhibit strong artifacts in the case the T-shirt was being worn, as shown in Fig. 6. In accordance with literature, artifacts caused by motion of the person wearing the intelligent garment are always present and require specific algorithms to be minimized [16-19]. However, the HBR can still be measured as the cardiac peaks are still

resolved and not masked by the artifacts.

Fig. 5:a) Cardiac signal versus time obtained with a) standard electrodes; b) textile electrodes and applied force with hand over electrodes regions; c) textile electrodes with narrower T-shirt. .

Fig. 4: SEMG signals (electrical signals versus time) obtained with sleeve and standard electrodes.

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Conclusions First steps were done toward the making of intelligent clothing integrating textile electrodes that are comfortable, non-intrusive, appealing in aspect and long-lasting. Two prototypes were made, a sleeve to monitor skeleton muscle activity and a T-shirt to monitor cardiac beat rate, based in a Clothing manufacture concept that uses embroidery electrodes of electrically conductive yarns on plain-weave tough fabrics that are sewed to elastic knits. The prototypes architecture was adapted to have the textile electrodes and inter-connects connecting to the described commercial wireless portable unit. The experiments accomplished with both prototypes indicated several issues. There is a need to apply a threshold pressure to the electrodes against the skin to prevent too high noise levels. The pressure achieved and maintained over time is very dependent upon the elastic knitting that makes the clothing. The knits must be resilient and able to conform in a tight manner to the body. The signal isolation regarding ambient interference must be integrated. In addition, a combination of filtering hardware and/or software to remove artifacts and ambient interference should be explored and applied. Acknowledgements The authors would like to thank Plux for ceding the BioPlux wireless portable unit, standard electrodes and software for the data recording. References 1.EU Project "Clevertex" on Multifunctional Intelligent Textile Materials, 1/10/2005 to 31/03/2008 (487,190€), available on-line on www.clevertex.net. 2.EU Project "Proetex" on Protection e-Textiles: MicroNanoStructured fibre systems for Emergency-Disaster Wear, 1/02/2006 to 31/01/2010, available on-line at www.proetex.org. 3.EU Project "Systex", on Coordination action for enhancing the breakthrough of intelligent textile systems (e-textiles and wearable microsystems), 30/04/2008 to 30/04/2011 (800,000€), available on-line at www.systex.org. 4.EU Project "Tremor", to validate, technically, functionally and clinically, the concept of mechanically suppressing tremor through selective Functional Electrical Stimulation (FES) based on a (Brain-to-Computer Interaction) BCI-driven detection of involuntary (tremor) motor activity, 1/09/2008 to 31/08/2011 (2,820,269€). 5.EU Project "Mobiserv", An Integrated Intelligent Home Environment for the Provision of Health, Nutrition and Mobility Services to the Elderly, 30/11/2009 to 30/11/2012 (3,600,742€), available on-line at www.mobiserv.eu. 6.EU Project "Psyche", Personalised monitoring SYstems for Care in mental Health, 1/01/2010 to 30/04/2013 (3,820,363€), available on-line at www.psyche-

project.org. 7.EU Project "Veritas", Virtual and Augmented Environments and Realistic User Interactions To achieve Embedded Accessibility DesignS, 1/01/2010 to 31/12/2013 (11,653,738€), available on-line at http://veritas-project.eu. 8. E. P. Scilingo et al., "Performance Evaluation of Sensing Fabrics for Monitoring Physiological and Biomechanical Variables", IEEE Trans. On Inf. Tech. in Biomed. 9, no.3, pp. 345-352 (2005). 9.on-line information at www.smartex.it. 10.on-line information on http://smartlifetech.com 11.on information www.meagemg.com 12.on-line information www.biodevices.pt 13. M. B. Schubert and J. H. Werner, "Flexible solar cells for clothing", Mat. Today 9, pp. 42-50 (2006). 14. information on-line at www.xslabs.net/skorpions/ 15. I. G. Trindade, J. Lucas, R. Miguel, P. Alpuim, M. Carvalho, N. Garcia, "Lightweight Portable Sensors for Health Care", presented at IEEE HealthCom International Conference, Lyon (2010), to be published. 16.X. Guo, Y. Li, W. Yan, "The SEMG Analysis For the Lower Limb Prosthesis Using Wavelet Transformation", Proceedings of the 26th Annual International Conference of the IEEE EMBS, S. Francisco, USA (2004). 17. S. H. Nawab, S. H. Roy, Carlo J. De Luca, "Functional Activity Monitoring From Wearable Sensor Data", Proceedings of the 26th Annual International Conference of the IEEE EMBS, S. Francisco, USA (2004). 18.R. Paradiso, G. Loriga, N. Taccini, "A Wearable Health Care Systems Based on Knitted Integrated Sensors", IEEE Trans. On Inf. Tech. in Biom. 9, no. 3, pp. 337-344 (2005). 19. P. Jourand, H. De Clercq, R. Puers, "Robust monitoring of vital signs integrated in textile", Sens. and Act. A 161, pp. 288-296 (2010).

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Hydrolysis of 3-alkyl-2-methylbenzoazol-3-ium iodides: an useful reaction S. S. Ramos 1, L. V. Reis 2, P. F. Santos 2, P. Almeida 3

1UMTP and Department of Chemistry, University of Beira Interior, 6200-001 Covilhã, Portugal; 2 Departamento de Química and Centro de Química – Vila Real, Universidade de Trás-os-Montes, Apartado 1013, 5001-801, Vila Real, Portugal; 3CICS,

Health Sciences Research Center, University of Beira Interior, 6201-001 Covilhã, Portugal Abstract The hydrolysis of 3-alkyl-2-methylbenzoazol-3-ium iodides in boiling ethanol in the presence of triethylamine was found to afford N-(2-hydroxyphenyl)- or N-(2-mercaptophenyl)-N-alkylacetamides, which are useful ortho-substituted aniline synthons.

Introduction Cyanine dyes have been extensively studied over the past century, mainly as photosensitisers for photography.1-3 In recent decades, other applications such as visible and near-infrared laser dyes,4-6 optical recording and storage media,3,4 biological fluorescent stains and probes,7 agents for photodynamic therapy,8,9 among others, have added renewed interest to the study and development of this family of dyes especially due to their absorption in the infrared region.

N-alkyl quaternary benzoazole ammonium salts are important precursors in cyanine dyes synthesis and they are used as end group-forming synthons, allowing the introduction of specific substituents both in the heterocycle and at the quaternary nitrogen atom. With such range of possibilities, these salts contribute to a large diversity of dye structures.10-15 In the present report, we describe the reaction of some heterocyclic salts which under residual water and basic conditions suffer heterocycle ring opening. The reaction between the quaternary ammonium salts 1 with water does not stop at the hydroxylated benzoazole compounds 2 as thought previously,.14,16,17 but cleavage of the heterocycle ring occurs to yield the corresponding N-(2-hydroxyphenyl)- or N-(2-mercaptophenyl)-N-alkylacetamides (scheme 1).

Scheme 1

Materials and Methods All reagents were purchased from Sigma-Aldrich and used without further purification. Solvents were of analytical grade. The 3-alkyl-2-methylbenzoazol-3-ium iodides were prepared heating under reflux a solution of 2-methylbenzoazole and the appropriate alkyl iodide, in acetonitrile, as described in the literature (step a), scheme 1).18 Reactions were monitored by thin layer chromatography (TLC) using 0.25 mm aluminum sheets pre-coated with silica gel 60 F254 (Merck). The TLC sheets were eluted with CH2Cl2/MeOH (9:1) and the spots examined under 254, 312 and 365 nm UV light. 1H and 13C NMR spectra were acquired on a Brücker ACP 250 NMR spectrometer (250.13 and 62.90 MHz). All spectra were recorded in CDCl3 at room temperature. Chemical shifts are reported in ppm using CDCl3 as an internal standard for the 1H and 13C spectra. General procedure for the hydrolysis of 3-alkyl-2-methylbenzoazol-3-ium iodides 1 to the corresponding N-(2-hydroxyphenyl)- or N-(2-mercaptophenyl)-N-alkylacetamides 3 A solution of 3-alkyl-2-methylbenzoazolium iodide 1 (1.0 mmol) and triethylamine (1.1 mmol) in 96% ethanol (100 mL) was heated under reflux. The reaction was complete

in 30 to 60 min. The solvent was removed under reduced pressure and the crude reaction product was dissolved in ethanol. Following the addition of sodium hydroxide (1.2 mmol with reference to salt 1) and the appropriate alkyl iodide (1.0 mmol), the reaction mixture was heated under reflux for more 2 to 5 hr. After completion of the reaction, the solvent was removed under reduced pressure, the crude residue was dissolved in CH2Cl2 and extracted sequentially with 10% aqueous HCl and 10% aqueous NaOH. The organic layer was then washed with water, dried over anhydrous Na2SO4 and evaporated to dryness. The resulting product is a pinky-red oil which is obtained in moderate to good yields (table 1). Results and Discussion This alternative synthetic route to N-(2-hydroxyphenyl)- and N-(2-mercaptophenyl)-N-alkylacetamides appears to be a useful and advantageous synthetic method compared to the usual electrophilic aromatic substitution starting from either thiophenol, phenol or aniline. By this strategy it is possible the selective introduction of different R1 and R2 substituents, which is not easily carried out starting from ortho-hydroxy- or ortho-thiohydroxy- substituted anilines.

55

As an example, NMR data for 2a: 1H NMR (250.13 MHz) 1.00 (t, J = 7.3 Hz, 3H, SCH2CH2CH3); 1.07 (t, J = 7.3

Hz, 3H, NCH2CH3); 1.63-1.73 (m, 2H, SCH2CH2CH3); 1.73 (s, 3H, C(=O)CH3); 2.85 (t, J = 7.0 Hz, 2H, SCH2CH2CH3); 3.16 (q, J = 7.0 Hz, 1H, NCH2CH3); 4.09 (q, J = 7.0 Hz, 1H, NCH2CH3); 7.08 (dt, J = 7.0 and 1.5 Hz, 1H, aromatic H); 7.15 (dd, J = 7.5 and 2.0 Hz, 1H,

aromatic H); 7.22-7.31 (m, 2H, aromatic H). 13C NMR (62.90 MHz) 12.7 (SCH2CH2CH3); 13.2 (NCH2CH3); 21.6 (SCH2CH2CH3); 21.9 (C(=O)CH3); 32.6 (SCH2CH2CH3); 41.7 (NCH2CH3); 124.7, 125.5, 128.20 and 129.24 (aromatic CH); 137.7 and 139.2 (aromatic C); 170.0 (C=O).

Table 1 – N-(2-hydroxyphenyl)- and N-(2-mercaptophenyl)-N-alkylacetamides overall yields and hydrolysis and alkylation time reactions

Salt 1 Step b) (min) Step c) (hr) Acetamide 3 Yield (%)

a, R1 = Ethyl 30 3 a, R1 = Ethyl; R2 = Propyl 91

b, R1 = Ethyl 30 4 b, R1 = Ethyl; R2 = Hexyl 76

c, R1 = Propyl 30 4 c, R1 = Propyl; R2 = Ethyl 85

d, R1 = Propyl 30 4 d, R1 = Propyl; R2 = Hexyl 73

e, R1 = Hexyl 45 5 e, R1 = Hexyl; R2 = Ethyl 63

X = S

f, R1 = Hexyl 45 5 f, R1 = Hexyl; R2 = Propyl 59

g, R1 = Ethyl 40 2 g, R1 = Ethyl; R2 = Propyl 84

h, R1 = Ethyl 40 2 h, R1 = Ethyl; R2 = Hexyl 62

i, R1 = Propyl 60 3 i, R1 = Propyl; R2 = Ethyl 87

j, R1 = Propyl 60 5 j, R1 = Propyl; R2 = Hexyl 57

k, R1 = Hexyl 60 4 k, R1 = Hexyl; R2 = Ethyl 64

X = O

l, R1 = Hexyl 60 5 l, R1 = Hexyl; R2 = Propyl 68

Conclusions The synthesis of some new N-(2-hydroxyphenyl)- and N-(2-mercaptophenyl)-N-alkylacetamides is presented as a regioselective, efficient and expeditious synthetic route to ortho-hydroxy- or ortho-thiohydroxy-substituted anilines, alternative to the classical electrophilic aromatic substitution starting from thiophenol, phenol or aniline.

References 1. West, W., Photograph. Sci. Eng., 18(1), 35-48, 1974. 2. Zollinger, H., in “Color Chemistry - Synthesis,

Properties and Applications of Organic Dyes and Pigments”, 2nd ed. Weinheim: VCH Publishers, 1991.

3. Sturmer, D., M., Heseltine, D., W., in James TH editor, “Sensitizing and desensitizing dyes - the theory of the photographic processes”, 4th ed., York, Macmillan, 1977.

4. Matsuoka, M. editor, in “Infrared absorbing dyes”, New York, Plenum Press, 1990.

5. Okawara, M., Kitao, T., Hirashima, T., Matsuoka, M., in “Organic colorants - a handbook of data of selected dyes for electro-optical applications”, Amsterdam: Elsevier Science Publishers B. V., 1988.

6. Fabian, J., Nakazumi, H., Matsuoka, M., Chem. Rev., 92, 1197-1226, 1992.

7. Haugland, R. F., in “Handbook of fluorescent probes and research chemicals, 7th ed., Molecular Probes, Inc., 1999.

8. Diwu, Z., Lown, W., Pharmac. Ther., 63, 1-35, 1994. 9. Wainwright, M., Chem. Soc. Rev., 351-359, 1996. 10. Tyutulkov, N., Fabian, J., Mehlhorn, A., Dietz, D.,

Tadjer, A., in “Polymethine dyes: structure and properties”, Sofia: St. Kliment Ohridsky University Press, 1991.

11. Bach, G., Daehne, S., in “Cyanine dyes and related compounds. In: Rodd’s chemistry of carbon compounds”, vol. IVb, Elsevier Science, 383-481 (chapter 15), 1997.

12. Mishra, A., Behera, R. K., Behera, P. K., Mishra, B. K., Behera, G. B., Chem. Rev., 100, 1973-2011, 2000.

13. Miltsov, S., Encinas, C., Alonso, J., Tetrahedron Lett., 42, 6129-6131, 2001.

14. Ramos, S., Santos, P. F., Reis, L., V., Almeida, P., Dyes Pigments, 53, 143-152, 2002.

15. Encinas, C., Miltsov, S., Otazo, E., Rivera, L., Puyol, M., Alonso, J., Dyes Pigments, 71, 28-36, 2006.

16. Nunes, M. J., Reis, L. V., Santos, P. F., Almeida, P., Tetrahedron Lett., 48, 5137-5142, 2007.

17. Pais, I. R., Nunes, M. J., Reis, L. V., Santos, P. F., Almeida, P., Dyes Pigments, 77, 48-52, 2008.

18. Ramos, S. S., Pardal, A. C., Serrano, P., Santos, P., Reis, L., Almeida, P., Molecules, 7, 320-330, 2002.

56

Non-Newtonian Flows in Two dimensional T-junctionsH. M. Matos 1, P. J. Oliveira 1

1Departamento de Engenharia Electromecânica, Universidade da Beira Interior,Rua Marques D’Ávila e Bolama, 6200-001 Covilhã, Portugal

Abstract A computational fluid dynamics simulation study has been carried out for steady and unsteady laminar flows in a planar 2D T-junction, using inelastic and viscoelastic non-Newtonian fluids.The present work aims to quantify the effects of flow rate ratio, inertia and elasticity upon the main flow characteristics in a dividing T-junction geometry, namely the size of the two recirculation zones created near the bifurcation and the stress fields. In hemodynamics such flow complexities are related to the genesis and development of vascular diseases, like the formation ofatherosclerotic plaques and thrombi.This study is also a first attempt to apply viscoelastic rheological models in bifurcation flows such as those which are relevant in hemodynamics.

Introduction Bifurcation flows are important in many engineering and bio-engineering applications. In engineering applications, bifurcations are commonly used in liquid distribution systems. However when the working fluid is composed by a mixture of a number of fluids and other materials like it may be found in dyeing processes in the textile industry or in the production process of paper, phase distribution inthe main and the branch ducts is inevitably different, affecting the flow control and processing facilities downstream. In some situations, like in the petroleum industries, this phenomenon is advantageous and is used to accomplish the first stage of oil and gas phase separation, with attending improvement in the efficiency of the transport system [1].In bio-engineering, bifurcation flow has strong relevance in hemodynamics, since it is well-known that vascular diseases tend to occur near the branches of arterial bifurcations [2, 3].

Figure 1 – Atherosclerotic plaques in a carotid bifurcation (Malek et al., 1999).

Atherosclerosis is the most common vascular disease. Itoccurs due to a damage of the endothelial cells in zones with small and oscillatory stress gradients [3], like those occurring in recirculation bubbles near arterial bifurcation (Fig. 1), and thus promoting the adhesion of platelets, red cells and lipoids into the endothelial wall (Fig. 2) [4].

Figure 2 – Atherosclerotic plaque formation (http://www.manualmerck.net/).

One of the principal areas of research investigating the cause of atherosclerosis is the role of blood flow and its interaction with the artery wall through the action of fluid shear stress. In many studies the blood is modelled as a Newtonian fluid; however blood is a complex fluid that consists of a suspension of platelets, leucocytes and erythrocytes in plasma [5], and possesses therefore non-Newtonian properties. Blood exhibits a shear-thinning viscosity, is thixotropic and viscoelastic [6].The present study aims to quantify the influence of inertia, elasticity, shear-thinning viscosity and flow rate ratio, on steady and unsteady laminar flows in a planar 2D T-junction. Inertia effects were varied through the Reynolds number (

1Re u H ), from 50 to 1000.

Elasticity properties were changed trough the variation of Deborah number (

1De u H ) and also the polymer

concentration (p sc ), whose increase corresponds to

reducing the viscosity ratio (s ). The shear-thinning

viscosity follows the Carreau-Yasuda model in which the power law exponent was changed according to the intensity of viscosity variation. Finally the flow rate ratio (

3 1Q Q ) varied from 0.1 to 0.9.

57

Numerical Simulation

Differential Equations For an incompressible flow, the equations to be solved are the conservation of mass (Eq. (1)) and the conservation oflinear momentum (Eq. (2)):

0 u (1)

(2 )Spt

u

uu D (2)

Where u is the velocity, p is the pressure, is the fluid

density, D is the rate-of-strain tensor and S is the

solvent viscosity. For the stress tensor in Eq. (2) we used different rheological constitutive models depending on whether the fluid is Newtonian, non-Newtonian inelastic or viscoelastic. For Newtonian fluids the stress tensor follows the Newton law for viscosity ( 2 ),

while for non-Newtonian inelastic fluids (Generalized Newtonian Fluids) the Carreau–Yasuda model [7] (Eq. 3) is followed to represent the viscosity variation with the shear rate.

1

0 1n aa

(3)

In Eq. (3) 0 and

are the zero and infinite shear rate

viscosities, is a constant time and n is the power law exponent. The magnitude of these parameters is obtained from [8].For viscoelastic fluids the FENE-CR model (Eq. 4) proposed by Chilcot and Rallison [9] was used.

( ) 2 pf

D (4)

is the relaxation time of the fluid at zero shear rate, the symbol denotes the Oldroyd upper convected derivative and the function ( )f is given by:

2 2( ) ( ( / ) ( ) ( 3)pf L tr L (5)

where 2L is the extensibility parameter ( 2 100L ,constant) and tr represents the trace operator.

Numerical MethodWe apply the finite-volume method on non-staggered meshes in which all variables are stored at the centre of cells forming the mesh [10]. The coupling between the velocity and stress fields employs the method of Oliveira et al. [11] later modified by Matos, et al. [12]. Spatial discretisation of the convective terms is accomplished with the high resolution scheme CUBISTA [13] and temporal discretisation of the unsteady term follows the three time level scheme [14]. The pressure-correction method employed is based on the SIMPLEC algorithm.

Geometry and Computational MeshThe simulations were carried out in a 2D T-shaped geometry (Fig. 3) having a constant cross section area with height H . The flow conditions were similar to those of Miranda et al. [6]. At the inlet, a parabolic velocity

profile was imposed for steady flows, while a pulsating flow generated by a sinusoidal pressure gradient was imposed for unsteady flows:

0 cos( )S

dpK K t

dx (6)

The ratio of oscillating and steady pressure gradients is

0 2.585SK K and the Womersley number is1 2 H .

At the outlets, Neumann boundary conditions were imposed. The other boundary planes are solid walls where the no slip boundary condition was imposed. The mesh is the same of Matos et al. [12] where a study of mesh refinement can be found, it is formed by 12800 control volumes and the minimum space is 42.5 10 , while the time step is 35 10 .

x

y

H

XS

Q1 Q2

Q3

Ytot = 21 H

Xtot = 26 H

H

XL XR

YL

YR

YS

H

Figure 3 – Schematic representation of the simulation geometry.

Results and DiscussionThe results presented are normalised: H length scale;

U H is the stress scale; and 2 / is the time scale.Depending of the flow parameters (Reynolds number, flow rate ratio, etc), T- Junction flows can promote the existence of one or two recirculation zones, which are represented in Fig. (3). The recirculation lengths change with inertia, elasticity, flow rate ratio, shear-thinning, for steady flows, while for unsteady flows they also changeduring the cycle.In Fig. (4) the separation and reattachment points of both recirculations are presented for a viscoelastic flow with constant elasticity ( 1De , 0.9 ), inertia ( 102Re )

and flow rate ratio ( 0.7 ). This figure shows that the horizontal recirculation is not present during the whole cycle, while the vertical recirculation is always present.However, in the latter case an abrupt reduction in length occurs after the middle of the cycle, which is associated with the breakup of the recirculation into two vortices; the red line (square symbols) corresponds to the first reattachment point (unique before the division) and the purple line (circular symbols) to the second reattachment point associated with a second recirculation that tends to disappear later in the cycle.

58

Elasticity was defined with De and for steady flows,

and only with De ( constant) for unsteady flows. In the

first case the reduction of results in a increase of the

polymer concentration ( 1c ), and elasticity.

Increasing De or reducing for steady flows (Fig. 5),

and increasing De for unsteady flows (Fig. 6), results on a decrease of the lengths of both recirculations, and an increase of the shear stress magnitude.

Figure 4 – , , ,S R S RX X Y Y variation (unsteady viscoelastic flow).

Figure 5 – Vertical recirculation length variation (steadyviscoelastic flow).

Figure 6 – Horizontal recirculation length variation (unsteady viscoelastic flow 0.9 ).

Inertial effects were analysed through the variation of Refor steady flows with both Newtonian and non-Newtonian inelastic fluids. The increase of Re results in higher recirculation lengths (Fig. 7) and shear stress magnitudes.In the case of non-Newtonian fluids there exists a viscosity depency with the shear rate, which affects the calculation of the Reynolds number. In order to maintain a comparable Reynolds number between the Newtonian and non-Newtonian flow cases as in the results of Fig (7),the average velocity imposed at inlet should be such that the corresponding characteristic shear rate (

1 0.5c U H )

yields a viscosity from Eq. (3) wich results in the desired Re ( 1Re cu H ).

Figure 7 – Recirculation lengths variation with Reynolds and flow rate ratio (steady GNF flow).

From Fig. (7) is also possible to observe the influence of flow rate ratio. Initially, the increase of results in the

increase of the recirculation lenghts, however for 0.6 ,the oposite behaviour is observed. This conclusion alsoholds for the unsteady case, where the flow rate ratio variation was analysed for viscoelastic cases (Fig. 8). The results for both type of fluids also show an increase of the shear stress magnitudes with .

For flows with non-Newtonian inelastic fluids, the intensity of shear-thinning in viscosity was varied trough the power law exponent ( n ) and analised for both steady and unsteady flows. In these cases the increase of shear-thinning (decrease of n ) results in a shight increase of

t0 0.2 0.4 0.6 0.8 1-1

0

1

2

3

4

5XSXRYS1YR1YS3YR3XS

XRYSYR

De=1.0

De0 2 4 6 8 10 12

1.6

1.7

1.8

1.9

2

=0.3=0.4=0.5=0.6=0.7=0.8=0.9

YL

t0 0.2 0.4 0.6 0.8 1

0

1

2

3

De=0.0De=1.0De=2.0De=3.0De=5.0De=10.0

XL

XX X X X X X X X X X X X X X X X X X X

Re0 200 400 600 800 1000

0

6

12

18

24=0.1=0.2=0.3=0.4=0.5=0.6=0.7=0.8=0.9

XXL

GNF(n=0.3568)

XX

XX

XX X X X X X X X X X X X X X X

Re0 200 400 600 800 1000

0

6

12

18

24=0.1=0.2=0.3=0.4=0.5=0.6=0.7=0.8=0.9

XYL

GNF(n=0.3568)

59

both recirculation lengths for the unsteady case (Fig. 9), while in the steady case a non monotonic behaviour was observed. The increase of shear-thinning also decreases the shear stress field.

Figure 8 – Horizontal recirculation length variation with

(unsteady viscoelastic flow).

Figure 9 – Recirculation lengths variation with n (unsteadyGNF flow).

The variation of the shear stress field with inertia,elasticity, shear-thinning viscosity and flow rate ratio was commented upon during the last section, however in all cases this field is characterized by low magnitudes of stresses in the recirculation zones and very high values in the re-entrante corners, as show in Fig. (10) for a steady viscoelastic flow ( 1De , 0.9 , 102Re , 0.7 ).

Figure 10 – Shear stress field (steady viscoelastic flow).

Conclusions This study based on computer simulations generally shows a decrease of both recirculation lengths with elasticity and an increase with inertia for steady and unsteady flows, while the variation with flow rate ratio does not present a monotone behaviour. For non-Newtonian inelastic flows it is necessary to adopt aconsistent Reynolds number in order to maintain the same value of Re as for the Newtonian case. When this is done, the influence of shear-thinning is minor.

References 1. Margaris, P.D., Chem. Eng. Proc., 46(2), 150, 2007.2. Ku, D., Annu. Rev. Fluid Mech., 29, 399, 1997.3. Berger, S.A. and Jou, L-D., Annu. Rev. Fluid Mech.,

32, 347, 2000.4. Liepsch, D., Moravec, S., Rastogi, A.K. and Vlachos,

N.S., J. Biomech., 15(7), 473, 1982.5. Anand, M. and Rajagopal, K. R., Int. J. Cardiovasc.

Med. Sci., 4(2), 59, 2004.6. Miranda A.I.P., Oliveira P.J. and Pinho F.T., Int. J.

Numer. Meth. Fluids, 57(3), 295, 2008.7. Carreau, P.J. Trans. Soe. Rheol., 16(1), 99, 1972.8. Banerjee, R.K., Cho, Y.I. and Kensey, K.R., Int. J.

CFD, 9(1), 23, 1997.9. Chilcott, M.D. and Rallison, J.M., J. Non-Newt. Fluid

Mech., 29, 381, 1988.10. Oliveira, P.J., Ph.D. Thesis, University of London,

1992.11. Oliveira, P.J. and Pinho, F.T., Numer. Heat Transfer

B, 35(2), 295, 1999.12. Matos, H.M.M., Alves, M.A. and Oliveira P.J.,

Numer. Heat Transfer B, 56(5), 351, 2009.13. Alves, M.A., Oliveira, P.J. and Pinho, F.T., Int. J.

Numer. Meth. Fluids, 41(1), 47, 2003.14. Oliveira, P.J., J. Non-Newt. Fluid Mech., 101 (1-3),

113, 2001.

AcknowledgementsH.M. Matos wishes to acknowledge the financial support provided by FCT trough the grant SFRH/BD/18062/2004.

XX X X

X

XX

XX

XX

X X X X X X XX

X

XX

XX

X

t0 0.2 0.4 0.6 0.8 1

0

1

2

3

4 =0.1=0.2=0.3=0.4=0.5=0.6=0.7=0.8=0.9

XXL

De=1.0

t0 0.2 0.4 0.6 0.8 1

0

1

2

3

n=0.1n=0.2n=0.3n=0.4n=0.5n=0.6n=0.7n=0.8n=0.9n=1.0

XL

=0.7

t0 0.2 0.4 0.6 0.8 1

0

1

2

3

n=0.1n=0.2n=0.3n=0.4n=0.5n=0.6n=0.7n=0.8n=0.9n=1.0

YL

=0.7

0.3 0

1

X-4 -2 0 2 4 6

0

2

4

6 XY

10.80.60.40.20.10

-0.1-0.2-0.4-0.6-0.8-1

Level 9 1.0288 1.027 1.016 15 0.34 03 -0.0022 -0.0041 -0.006

Y

De=1.0

60

Comparative study of fibres for Eucalyptus globulus based paper using

experimental characterization and 3D paper modeling Curto, J.1, Conceição, E.2, Portugal, A.2, Simões, R.1

1University of Beira Interior, Textile and Paper Materials Research Unit, 2 University of Coimbra, Research Centre for Chemical Processes Engineering and Forest Products (CIEPQPF)

Abstract We present a comparative study of different fibres that are important to produce and optimize an Eucalyptus based paper. The work includes an extensive experimental characterization and the developing and implementation of an innovating three dimensional paper model The 3D paper structure is formed by individual fibres and for the first time the fibre model includes fibre wall thickness and fibre lumen with a resolution up to 0.05 µm. In the present work, we use our simulator to compare the fibres of Eucalyptus globulus and two important reinforcement fibres, the Portuguese Pinus pinaster and a Nordic Picea abies. The influence of key parameters, such as fibre wall thickness, fibre flexibility and fibre collapsibility, on paper characteristics was determined by both experimental and computational ways. The resulting porous network structure was characterized using properties like porosity and paper sheet thickness. It can be concluded that the model is able to reproduce real paper structures.

Introduction Office paper is the principal Portuguese paper industry product. This paper is mainly produced from Eucalyptus globulus bleached Kraft pulp with a small incorporation of a softwood pulp, called reinforcement pulp, to increase paper strength. It is important to access the contribution of different reinforcement pulp fibres with different biometry and coarseness to the final paper properties. The two extremes of reinforcement pulps are represented by a Picea abies kraft softwood pulp, usually considered the best reinforcement fibre, and the Portuguese pine Pinus pinaster kraft pulp, recently made commercially available. The Portuguese fibre exhibits higher coarseness (45%), length (13%) and width (15%) than the market softwood. To evaluate the impact of this morphology differences on paper properties the experimental plan design includes the following steps: evaluation of each raw material separately and its evolution with beating; preparation of isotropic paper hand sheets; testing paper regarding structural, mechanical and optical properties. Having identified the morphological differences between fibres, as well as the fibre flexibility evolution during beating, as the main factors responsible for the differences in the final paper properties, it become our goal to implement a paper model that allowed us to change this factors in a systematic way. Many authors have identified the importance of fibre properties, specially fibre transverse dimensions and mechanical behavior (flexibility and collapsibility), on paper properties. Unfortunately, several of the fibre

dimensions change simultaneously when changing a raw material. Also, both mechanisms of fibre flexibility and collapse occur simultaneously in papermaking. Therefore, it is hard to quantify the effect of each cause individually in experiments. However, this can be easily accomplished with computational simulations. The model intends to capture key paper making fibre properties, like morphology, flexibility and collapse. The model also includes process operations like fibre deposition, network forming and densification. It is a deposition-like model based on the KCL-PAKKA model, but extended to simulate fibre interactions, and also a novel fibre microstructure model that includes fibre lumen. The 3D paper structure is formed by individual fibres, deposited one at a time, which conform to the underlying structure, depending on its position, dimensions and flexibility. The model simulates fibre interactions, like flocculation and hydrodynamic smoothing. In an original form, the fibre model includes fibre wall thickness, and fibre lumen, with a resolution up to 0.05 µm. The model implemented is based on the KCL-PAKKA model proposed by Niskanen and Alava in 1994 [1]. In this model, the three-dimensional structure of paper is simulated using a sedimentation-like or growth process. The sedimentation model of paper assumes that the sheet is formed from a dilute suspension under the influence of an uniform flow field. In its initial assumption all fibre interactions are ignored. The model proposed by Niskanen and Alava is the first to include fibre flexibility and capture the truly nature of paper. Departing from fibre dimensions and flexibility a three dimensional structure is formed and various paper properties are predicted. The simulations obtained are consistent with experimental data as presented by Alava and Niskanen in 2006 and Niskanen et al. [2] [3]. Besides the standard KCL-PAKKA model an extension of this model which incorporates a formation control parameter is implemented. This modification is based on the sedimentation rule developed by Provatas e Useaka in 2003 [4]. Moreover, in our model the lumen is introduced for the first time, allowing the study of the influence of fibre collapse and a more realistic simulated structure. Materials and Methods The pulps used in this study are identified as follows: • Eucalyptus globulus bleached Kraft pulp (EUC); • Picea abies bleached Kraft pulp, Nordic reinforcement fibres (FL); • Pinus pinaster bleached Kraft pulp, Portuguese reinforcement fibres (PB).

61

Kappa number and pulp viscosity were evaluated according to the ISO 302 and ISO 5351/1 standard methods. The Portuguese pine pulp was bleached with O2 in the industrial plant (kappa = 25) followed by laboratory bleaching using a D1E2D2 sequence. The final pulp viscosity was 830 ml/g. The morphological properties of pulp fibres were determined automatically by image analysis of a diluted suspension (20mg/L) in a flow chamber in Morfi® (TECHPAP, Grenoble). The pulps were beaten in a PFI mill at 1000, 3000 and 6000 revolutions under a refining intensity of 3.33 N/mm. Wet fibre flexibility (WFF) was determined according to the Steadmenan and Luner procedure [5], using CyberFlex® from CyberMetrics. The experimental method includes the formation of a very thin and oriented fibre network on top of a glass slide with parallel wires. The fibre suspension is deposited using a paper machine head-box, simulating the real paper formation. It is followed by the transferring from the textile wire to a glass slide, with metal wires, under controlled pressure conditions. An image analysis software analysis is used. Paper hand sheets were prepared according to ISO Standards, and tested regarding structural, mechanical and optical properties. Results and Discussion Pulp Fibre characterization Table 1 presents the principal morphological properties for the three pulps under investigation. The Eucalyptus fibres are considered ideal office paper fibres due to their relatively high coarseness when comparing with other hardwood fibres (short fibres). The Portuguese fibre (PB) exhibits higher coarseness (45%), length (13%) and width (15%) than the corresponding Nordic softwood (FL). Figure 1 represents the Wet Fibre Flexibility evolution during beating. Table 1 – Fibre morphology Market

softwood (FL)

Portuguese Pine (PB)

Eucalyptus

(EUC) Fibre length weighted in

length (mm)

1.79 2.03 0.80

Fibre width (μm)

29.4 33.8 18.00

Coarseness (mg/m)

0.151 0.219 0.067

Figure 1 – Evolution of Wet Fibre Flexibility with beating

Beating of individual pulps

The behaviour of fibres with beating (Figure 2) indicates that coarser fibres beat slower than thin fibres, measured as Shopper Riegler degree.

0

10

20

30

40

50

60

0 1000 2000 3000 4000 5000 6000

PFI, rev.

ºSR

EUC

FL

PB

Figure 2 – Evolution of Shopper Riegler with beating

The paper structure obtained from coarse fibres (with higher fibre wall thickness) densificates slower, and to a lower final value, than the paper made from thin fibres, with thinner fibre walls (Figure 3).

0.5

0.55

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0 1000 2000 3000 4000 5000 6000

PFI, rev.

Pap

er d

ensi

ty,

g/c

m3

EUC

FL

PB

Figure 3 – Evolution of paper density with beating

The results indicate that the two softwood pulps exhibit similar relationships between tensile index and paper density (Figure 4). At a given tensile, the Portuguese pulp shows higher tear resistance than the corresponding Nordic pulp (Figure 5).

10

20

30

40

50

60

70

80

90

0.5 0.6 0.7 0.8 0.9

Density, g/cm3

Ten

sile

I.,

N.m

/g

EUC

FL

PB

Figure 4 – Evolution of strength with paper density

62

0

5

10

15

20

25

10 20 30 40 50 60 70 80 90

Tensile I., N.m/g

Tea

r I.

, m

N.m

2 /gEUC

FL

PB

Figure 5 – Tear index vs. tensile index

Table 2 presents the paper porosity evolution with beating for hand sheets with 60 g/m2. Pulps are beaten to achieve similar ºSR.

Table 2 – Paper porosity evolution with beating EUC

PB FL

No beating 0,65 0,67 0,66 Pulps beaten with similar

ºSR

0,55 0,55 0,53

Comparative study of paper thickness using SEM

photographs and model simulations

The visualization of SEM images with different beating degrees puts in evidence different fibre flexibility and collapsibility (Figures 6, 7, 8, 9, 10, and 11). The samples presented are thickness cuts from laboratory hand sheets with 60 g/m2. Tables 3, 4, 5 and 6 summarize the measurement results made from several SEM images using a software available at the University of Beira Interior Optical Centre. The quantification was done with statistical representative samples that are available for consultation. To be included in this communication only one of each was chosen.

Figure 6 – SEM paper thickness EUC 0 PFI revolutions

Figure 7 – SEM paper thickness EUC 3000 PFI

revolutions Table 3 – Paper and fibre thickness SEM measurements

for EUC fibres EUC

(0 rev) EUC (3000 rev)

Paper thickness (µm)

95 62

Model thickness (µm)

94 62

FiguFigure 8 – SEM paper thickness PB 0 PFI revolutions

63

Figure 9 – SEM paper thickness PB 6000 PFI revolutions

Table 4 – Paper and fibre thickness SEM measurements for Portuguese pine fibres PB

Pinus pinaster (0 rev)

Pinus pinaster (6000 rev)


95 76

Model thickness (µm)

94 77

Figure 10 – SEM paper thickness FL 0 PFI revolutions

Figure 11 – SEM paper thickness FL 3000 PFI

revolutions

Table 5 – Paper and fibre thickness SEM measurements for market softwood fibres FL

Picea abies (0 rev)

Picea abies (3000 rev)


80 67

Mdel thickness (µm)

80 69

The analysis made from SEM images points out that fibre wall thickness and collapse degree are key parameters. To study the influence of fibre dimensions and flexibility, a paper model was developed and implemented. The paper simulations agreed with experimental determinations and were used to separate the effect of fibre flexibility and fibre collapse on paper densification [6]. Conclusions An experimental design was devised in order to quantify the influence of the raw material and beating degree on paper properties, for the long and short paper fibres. The resulting porous structure was characterized and the mechanical performance was determined. The analysis was carried out from the consorting of fibre morphology, Wet Fibre Flexibility, SEM photographs and characterization of laboratory isotropic handsheets. Comparing the simulation results with the laboratory handsheets, we found that the model is able to reproduce paper structures and that it followed well the behavior of the experimental handsheets. Moreover, simulations indicate that both fibre flexibility and fibre collapse interact and have a significative effect on the fibre web structure densification

References 1. Niskanen, K., Alava, M., “Planar random networks with

flexible fibres”, Phys. Rev. Lett., 73(25):3475 (1994). 2. Alava, M., Niskanen, K., “The physics of paper”,

Reports on Progress in Physics, 69(3):669 (2006). 3. [Niskanen, K., Nilsen, N., Hellen, E., Alava, M., “KCL-

PAKKA: simulation of 3D structure of paper”, 11th FRS, pp. 1273-1291, September (1997).

4. Provatas, N., Uesaka, T., “Modelling paper structure and paper press interactions”, JPPS, 29(10):332 (2003).

5. Steadman and Luner, P.; Wet Fiber Flexibility as a Index of Pulp and Paper properties, PIRA International Conference on “Advances in Refining Technologies”, Birmingham, England, Vol.1, Session 1, Paper 3, (1986).

6. Curto, J., Conceição, E., Portugal, A., Simões, R., “Three dimensional modelling of fibrous materials and experimental vaidation, Material Wissenschaft und Werkstoff Technik (ISI 343), Wiley, In press.

64

Electrocoagulation of leachates from sanitary landfills P. Rodrigues, D. Norma, M.J. Pacheco, L. Ciríaco, A. Lopes

UMTP and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal Abstract The influence of the initial pH, applied potential and stirring on the electrocoagulation/electrofloculation of samples from real leachates was studied. Samples were collected at a sanitary landfill, in different times of the year. In order to choose the best experimental conditions to obtain, after the electrochemical treatment, a mixture with good characteristics for a quick sedimentation/ flotation, suspended (SS) and dissolved solids (SD) and chemical oxygen demand were determined. Introduction Although the European Union Landfill Directive (1999/31/EC) has been built on the concept of landfill ban (progressive banning of municipal biodegradable wastes from landfill to achieve 35% of 1995 levels by 2020), landfilling is often regarded as the last resort waste management option [1]. This type of garbage disposal leads to the formation of leachates, defined as aqueous effluents generated as a consequence of rainwater percolation through municipal landfills and containing organic compounds, heavy metals, ammonium, chloride and many other soluble compounds [2,3]. The changing nature and composition of leachates depending on age, climatic conditions, etc., implies that universal treatments of wide application can not be proposed. Although biological processes have shown a good performance in the treatment of readily biodegradable landfill leachate, the biodegradability of a leachate decreases with the age of the landfill [4]. The poor biodegradability of old landfill leachates implies that, in most cases, a single technology is not enough to achieve acceptable levels of pollution decrease and combined bio-physical-chemical processes have to be performed [3]. Some of the physical-chemical studies include the use of technologies such as coagulation–flocculation, adsorption on activated carbon, chemical oxidation and membrane processes [1]. Membrane technology, namely ultrafiltration and reverse osmosis, are used in several Portuguese landfill facilities, after a nitrification/denitrification biological system, to eliminate organic and inorganic contents from leachates. Although membrane processes are very effective in the removal of pollutants from effluents, they left a more concentrated solution that, in the case of leachates, is usually returned to the biological treatment pond, thus increasing its concentration in organic and inorganic loads. An emerging technology to treat effluents containing persistent pollutants that has received great development in the last years involves electrochemical techniques. Even for leachates, there are also a few studies using electrocoagulation, electro-Fenton and anodic oxidation.

Deng and Englehardt [5] present an overview of the electrochemical oxidation processes used to treat landfill leachates. In this work, samples from real leachates, collected in different times of the year, were treated by an electrocoagulation/flocculation technique, using iron consumable anodes, in order to remove suspended solid and part of the organic and inorganic load of the samples. Particular attention will be focused on the attainment of a suspension with good sedimentation characteristics that will allow a good separation of the deposited and supernatant phases from the clear solution. Materials and Methods All the electrochemical assays were performed in potentiostatic mode, at applied potentials ranging from 2 to 6 V, using iron electrodes as consumable anodes. A volume of 150 mL was used in all the experiments. Tests were followed by UV-Visible spectrophotometry, with absorbances being measured from 200 to 900 nm, using a UNICAM -Heλios-α UV/VIS spectrophotometer, by Chemical Oxygen Demand (COD) tests, using the closed reflux dichromate titrimetric method [6], and by suspended (SS) and dissolved solids (DS) measurements, performed according to standard procedures [6]. Results and Discussion Table 1 presents the initial values for the parameters SS, SD and COD for the raw leachate collected at the sanitary landfill. Table 1. COD, SS and SD for the raw samples collected at the entrance of the biological treatment.

Sample SS / g L-1

SD / g L-1

COD / mg O2 L

-1

April 2009 1.5 14.7 10829

July 2010 0.94 26.8 12969 Figure 1 presents the results obtained for the samples after the electrocoagulation treatment performed in different experimental conditions. We can observe that, at natural pH, with stirring, the highest values for SS and lowest values for SD and COD are obtained. These are the best results, since high SS means an easy removal of the undesirable material. On the other hand, low SD and low COD leads to an easier removal of the posterior organic load by, for instance, anodic oxidation. In Figure 2 we can observe the results obtained for a different sample, collected in the end of July 2010, in similar experimental conditions.

65

0

0,5

1

1,5

2

2,5

4 V 5 V 6 V

X /

X0 SS

SD

COD

April 2009 natural pH without stirring

0

1

2

3

4

5

4 V 5 V 6 V

X /

X0 SS

SD

COD

April 2009 natural pH with stirring

0

1

2

3

4

4 V 5 V 6 V

X /

X0 SS

SD

COD

April 2009 pH=12 with stirring

Figure 1. Results for the assays performed at various applied potential, with the sample from April 2009, at natural pH (≅ 9), with or without stirring, and with initial correction to pH (≅ 12) and stirring. Conclusions The electrocoagulation of two different samples from real leachates was performed in different experimental conditions with success. However, no general conclusions could be drawn. Apparently, the initial characteristics of the initial sample are determining to choose the ideal experimental conditions to obtain suspensions with good steeling characteristics. References 1. F. J. Rivas , F. Beltrán, F. Carvalho, O. Gimeno, J.

Frades (2005). Ind. Eng. Chem. Res. 44, 2871-2878. 2. A. Cabeza, A. Urtiaga, M.-J. Rivero, I. Ortiz (2007).

Journal of Hazardous Materials 144, 715–719. 3. Cabeza, A., Primo, O., Urtiaga, A.M., and Ortiz, I.,

Sep. Sc. Technol., 42, 1585, 2007. 4. Chiangui, L.-C., Changui, J.-E., and Wen, T.-C., Wat.

Res. 29, 671, 1995. 5. Deng, Y., and Englehardt, J.D., Waste Management

27, 380, 2007. 6. Eaton, A., Clesceri, L., Greenberg, A., Standard

Methods for Examination of Water and Wastewater. APHA, AWWA, WEF, 21st Ed., Washington, 2005.

0

0,5

1

1,5

2

4 V 5 V 6 V

X /

X0 SS

SD

COD

July 2010 natural pH without stirring

0

0,2

0,4

0,6

0,8

1

1,2

4 V 5 V 6 V

X /

X0 SS

SD

COD

July 2010 natural pH with stirring

0

0,5

1

1,5

4 V 5 V 6 V

X /

X0

SS

SD

COD

July 2010 pH=9 with stirring

0

1

2

3

4

5

6

4 V 5 V 6 V

X /

X0 SS

SD

COD

July 2010 pH=12 with stirring

Figure 2. Results for the assays performed at various applied potential, with the sample from July 2010, at natural pH (≅ 8), with or without stirring, or with an initial correction to pH (≅ 9 and 12) and stirring. Acknowledgements The financial support of Fundação para a Ciência e a Tecnologia, FCT, PTDC/AAC-AMB/103112/2008, and Resistrela are gratefully acknowledged.

66

The homogeneity of the structure of spunbonded nonwovens Rita Salvado 1, Jacques Silvy 1

1Universidade Beira Interior, Unidade Materiais Têxteis e Papeleiros Abstract The spunbonded, as other nonwoven and tissue-paper materials, are heterogeneous structures used in several fashion applications, such as package. The visual observation of the materials give relevant information that might guide designers to better select the material best adapted to the final product. This paper presents an exercise on visual classification of samples that might be used to train fashion designers in their learning process about selecting nonwovens. Therefore, in this work, the homogeneity of laboratory spunbonded webs is defined considering the mass uniformity and the size of the grain that are visually observed. This subjective analysis is validated by objective estimations of the homogeneity of the webs. It is experimentally verified that the air through permeability depends on the homogeneity of the spunbonded, decreasing with it. Introduction In this paper the structure of spunbonded nonwovens is characterized in terms of its visual appearance, based on the uniformity of the mass, i.e. homogeneity. Indeed, homogeneity is the first property one look for when evaluating the quality of the material. However, the visual appearance is subjective, which makes difficult the understanding and the classification of homogeneity. Therefore, in this paper, the homogeneity of the spunbonded is related to the variation of mass. Materials and Methods The spunbonded samples A group of 160 laboratory samples were considered in this analysis. They were produced varying the manufacturing process parameters but keeping the mass per unit area, i.e. grammage, W, constant and equal to 17 g/m2. They are spunbonded thermal point bonded nonwovens, composed of circular polypropylene filaments. Each web is composed of filaments with equal mass per unit length, w, but among the several webs the values of w vary from 2.1 to 3.9 dtex. As consequence of the constant grammage, the surface length of the nonwoven, Ls [L-1], i.e. the cumulative length of the filaments per unit area of the web, given by Ls=W/w, will evidence the thickness of the component filaments, specifically the inverse correlation between Ls and the squared diameter of the filaments. The wide variety of mass uniformity of the structure of the samples is visually observed. Some webs are clearly heterogeneous, presenting agglomerates of filaments, i.e. grains, alternating with low dense zones. It is visually observed that the homogeneity of the web increases with the size of these grains. Indeed, grains join together by juxtaposing or superposing in the planar structure.

Evaluating Homogeneity Several techniques and methods have been proposed to classify the uniformity of planar fibrous materials. Some are based on the correlation between the visual appearance and some physical properties of the material, as for instance the local mass variation [1] or the optical density variation [2 – 8]. Despite the subjectivity of the visual ranking process, it remains the most approachable and practiced method to estimate the homogeneity of the webs. Thus, in this study, three persons have visually ranked the 160 samples in terms of their appearance, having as guidelines some previously accorded criteria. A preliminary observation of the samples and preliminary discussions about the meaning of good and bad look led to the definition of the criteria of ranking, as shown in table 1. Additionally, some samples were chosen as references to guide the visual observation. Table 1 – The visual ranking criteria and scale To exemplify the wide variety of visual appearances existing in the domain of study, figure 1 shows images of two samples. The nonwoven on the left was classified H=2 (uneven) and the nonwoven on the right was classified H=4 (even). The values have no mean in absolute terms as they are set in comparison with the samples references. Figure 1 – The visual appearance of two samples (scanned area = 9 × 8 cm2)

67

Results and Discussion The results of the ranking are shown in figure 2. The dots signed with a square will be pointed below in this paper. As one can see, homogeneity correlates with the size of the grain, increasing with it. This means both criteria, from table 1, were dependent, putting in evidence the subjectivity of the visual ranking. Figure 2 – The correlation between homogeneity, H, and the size of the grain, G Figure 3 shows that the homogeneity of the webs significantly increases with their surface length, SL. At constant grammage, thinner filaments correspond to higher SL. Higher SL means smaller pores, i.e. a better covering of the web surface by the filaments, improving by this way the uniformity of the nonwoven. Figure 3 – The homogeneity and the surface length, SL, of the samples The influence of the uniformity on the permeability of the web The visual evaluation of the homogeneity of the materials might be used to quickly evaluate the relative variation of some physical properties, as it will be shown for the air through permeability. The fluid flow in a porous medium is generally described by relationships between the gradient of pressure through the medium and the flow velocity. In previous work [9], it was shown that the airflow through the spunbonded is non linearly related to the gradient of pressure. Nevertheless, under a low pressure drop, as for instance 100 Pa, the air

through permeability, B [L2], of the material is well estimated by Darcy’s law, given by equation 1, where v is the rate of flow per unit area through the spunbonded, ı is the dynamic viscosity of the air and ΔP is the pressure drop over the thickness h of the sample.

h

PBv

Δ⋅=

μ Eq.1

In this condition, the permeability in the direction ı of a homogeneous porous medium is defined in terms of the structure of the medium and is given by:

( )γγ

γε

εε

kSk

d

B

h

⋅−⋅=

⎟⎠⎞

⎜⎝⎛

⋅

= 220

3

2

1

4 Eq.2

where ε [-] is the porosity of the nonwoven, dh [L+1] is the

hydraulic diameter, kγ [-] gives the tortuosity tγ as defined by the Kozeny-Carman law (kγ= k0.tγ

2, being k0 the shape

factor of the capillary cross section) and S0 [L-1] is the surface per unit volume of the filaments. The value of S0 puts in evidence the influence of the diameter of the filaments, d, as S0=kf/d, where kf is a shape factor, equal to 4 for a circular cross section. Thus, at constant grammage, the permeability will evidence the influence of the linear mass of the filaments and of the squared diameter of the filaments. With the purpose of analysing the influence of the homogeneity on the air permeability through the nonwovens, some samples were tested using a standard equipment. The tested samples were signed with a square in the previous figures 2 and 3. A pressure drop, ΔP, of 100 Pa was imposed and the corresponding air velocity through the sample, v, was recorded. Because of the fact that the spunbonded are point bonded, the driven specimen area is reduced on the proportion of the bonded area that is estimated equal to 10%. Thus, the measured v values were corrected dividing by 0,9. The scale of the experimental analysis was adjusted in order to sense the heterogeneity of the materials. A large sample scale was considered in order to homogenize the structure of the web. A small scale was also considered in order to record the heterogeneity of the structure. Among the available test conditions, two specimen areas were thus considered: 20 cm2 and 5 cm2 for the large and small scales respectively, performing 15 and 30 measurements, respectively. It should be noted that 5 cm2 is slightly higher than the mean area of the visually observed grains. The experimental results for the air permeability measurements through the spunbonded are shown in Figures 4-A and 4-B, where the mean and standard deviation values, respectively, are plotted against the visual homogeneity.

0

1

2

3

4

5

0,0 0,5 1,0 1,5 2,0 2,5 3,0Grain size [-]

Ho

mo

gen

eity

[-]

0

1

2

3

4

5

40 50 60 70 80 90Surface Length [Km/m2]

Ho

mo

gen

eity

[-

]

68

Figure 4 – The mean air through permeability and its standard deviation (under ΔP=100 Pa)

As expected, the air permeability through the nonwovens decreases with homogeneity (fig. 4-A). Basically, like the homogeneity of the webs increases with the surface length SL so the mean permeability decreases with the SL and so increases with the squared diameter of the filaments. Logically, the standard deviation values of the measurements using a specimen area of 5 cm2 are higher that the ones corresponding to a specimen area of 20 cm2, (fig. 4-B). Moreover, the difference between these values decreases with homogeneity, enhancing the validation of the results of the visual ranking method. Figure 4-B shows the correlation between the visual homogeneity evaluation and the standard deviation of the air permeability data. The data obtained with a probe area of 5 cm2 clearly points out two samples – dots at H=1,0 and H=2,9 – whose visual homogeneity was probably wrongly evaluated. This observation could be partially made on the previous figures 4-A and 3. This puts in evidence the limitations of the subjective visual evaluation of the homogeneity. The coefficient of determination r2 of the linear regression was 0,952 and 0,612 respectively for the 5 and 20 cm2 data, excluding the two referred dots. One may conclude that the standard deviation of the air permeability results, obtained with a probe area of 5 cm2 may be used to objectively evaluate the homogeneity of the web. Conclusions The visual observation of the spunbonded allows evaluate the homogeneity of the materials and quickly evaluate the relative variation of some physical properties, as it was shown for the air through permeability. Despite the subjectivity of the visual homogeneity ranking, the results are well correlated with the standard deviation of the permeability measurements. Thus, the standard deviation may be used to objectively estimate the homogeneity of the spunbonded. References

1. Herdman, P.T., “Measurement of the distribution of mass density in paper”, Paper Tech. Ind., p.246, Sept.(1978).

2. Hellawell, J.M., “Analysis of the small-scale distribution of mass density in paper by beta-radioghraphy”, Paper Tech. Ind., p.24, Feb.(1973).

3. Cresson, T.M., Tomimasu, H., Luner, P., “Characterization of paper, Part 1: Sensing of paper formation”, TAPPI J. 73 (7): 153(1990).

4. Cresson, T.M. and Luner, P. “The Characterization of paper formation, Part 2: The texture analysis of paper formation”, TAPPI J. 73 (12): 175(1990).

5. Huang, X.C. and Bresee, R.R., “Characterizing nonwoven web structure using image analysis techniques, Part II: Web uniformity analysis”, INDA J. Nonwoven Research 5(3): 28( 1993).

6. Bernié, J-P. and Douglas, W.J.M., “Local grammage distribution and formation of paper by light transmission image analysis”, TAPPI J. 79 (1): 193(1996).

7. Johansson P-Å. and Norman, B., “Methods for evaluating formation, print unevenness and gloss variations developed at STFI”, TAPPI 1996 Process and Product Quality Control Conference Proceedings, TAPPI PRESS, Atlanta, p.139.

Acknowledgements The authors wish to thank the Rieter-Perfojet company for supplying the samples.

0,0E+00

5,0E-11

1,0E-10

1,5E-10

2,0E-10

2,5E-10

0,0 1,0 2,0 3,0 4,0 5,0

Homogeneity [-]

Air

th

rou

gh

per

mea

bil

ity

[m2 ]

20 cm2

5 cm2

0E+00

1E-11

2E-11

3E-11

4E-11

5E-11

0,0 1,0 2,0 3,0 4,0 5,0

Homogeneity [-]

Std

Dev

B [

m2 ]

20 cm2

5 cm2

BA

69

Influence of pH on the molecular structure of four azo dyes M.J.R.G. Pires1, M.I.A. Ferra1, A.M.M.M.B. Amaro1, I.M.S.C. Gonçalves1

1 Chemistry Department, University of Beira Interior, 6201-001 Covilhã Abstract Acid-base properties of four azo dyes, methyl orange, acid orange 7, acid orange 8 and acid red 151, were studied by means of spectrophotometric measurements of dye solutions, using water or pH buffers as solvents. From the absorbances measured at different pH, acidity constants were determined for the monoazo dyes: pKa = 3.61±0.20 (MO); pKa = 11.21±0.14 (AO7); pKa = 11.57±0.17 (AO8). For the diazo dye, AR151, precipitation was visible at very low pH and an acid-base equilibrium was not observed in these experimental conditions. Introduction Dyes are soluble compounds that have great affinity for several substrates used in dyeing processes in textile, paper, cosmetics, pharmaceutical, food industries, among others, and the amount of those substances rejected to the effluents is still very high. It is estimated that about 15 % of the total production of colorants is lost during synthesis and processing which corresponds to a daily worldwide release of about 128 tons to the environment [1]. The main source of this loss is due to incomplete exhaustion. Therefore the major environmental problem associated with colorants is their removal from effluents and methods for decolourisation have become important in recent years, namely, adsorption, aerobic or anaerobic biological treatment, chemical oxidation, coagulation, membrane technologies, among others. In principle, a complete decomposition to CO2, H2O, NO3

-, SO42-, Cl-,

etc., would be possible after prolonged treatment by a combination of the above methods. This would be the ideal situation. In this context, it is therefore important the study of dyes properties in order to elucidate more clearly the conditions for a more complete exhaustion onto the fibers, reducing their concentration in the effluents. On another hand, the improvement of the mechanisms involved in the treatment processes is also important. Reports on physical and chemical properties of dyes are scarce in the literature. The aim of this work is a study on the influence of pH on the molecular structure modification of four azo dyes. Acidity constants of three monoazo dyes were determined by means of spectrophotometric measurements [2]. Materials and Methods Four azo dyes, methyl orange - MO (85 %), acid orange 7 – AO7 (85 %), acid orange 8 – AO8 (65 %) and acid red 151 – AR151 (40 %), purchased from Sigma-Aldrich, were used with no further purification. Their molecular structures are shown in figure 1.

Fig. 1 - Molecular structure of dyes: MO (A); AO7 (B); AO8 (C); AR151 (D) The following buffer solutions were prepared [3]: HCl 1 M (Fixanal ampoules, Fluka); HCl 0.1 M; HCl 0.01 M; HCl 0.001 M; KHPh (potassium hydrogen phthalate) 0.05 M (99,5 %, Fluka); HAc (acetic acid) 0.01 M (99/100 %, Pronalab) + NaAc 0.01 M (99 %, Riedel-de-Haën); KH2PO4 0.025 M (Merck) + Na2HPO4 0.025 M (Merck); Na2B4O7·10H2O 0.05 M (Merck); NaHCO3 0.02 M (99.5 %, Fluka) + Na2CO3 0.01 M (99.5 %, Fluka) - the amounts of these two salts varied in order to obtain pH values within 9.60 - 10.19; CH3(CH2)3NH2 0.2 M(99.5 %, Fluka) + HCl 0.1 M - the amounts of the two substances varied in order to obtain pH values within 10.35 – 10.86; NaOH 1 M (Titrisol ampoules, Merck); NaOH 0.1 M; NaOH 0.001 M. Purified water, with a resistivity of 18 MΩ·cm, obtained by Milli-Q185 Plus (Millipore), was used in the solutions preparation. Uv-visible spectra were run in a Heλios γ spectrophotometer. The pH meter (Metrohm, 605) was calibrated with standard buffer solutions of pH = 4.00 and pH = 7.00. The experiments were carried out at room temperature (20 – 25 ºC). Results and Discussion The spectra of the four mentioned dyes were run, in the wavelength range 200 – 600 nm, for dye solutions with water or pH buffers as solvents. A few of them are depicted in figure 2. The MO spectra (fig. 2, I) reveal that the unprotonated species, that gives yellow colour to the solution, remains unchanged in the solution, even at high pH values and the protonated ion [4] (red) is formed when the hydrogen ion concentration is sufficiently high.

(A)

(B)

(C)

(D)

70

0,0

0,2

0,4

0,6

0,8

1,0

1,2

200 250 300 350 400 450 500 550 600

Wavelength / nm

Ab

sorb

ance

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

200 250 300 350 400 450 500 550 600

Wavelength / nm

Ab

sorb

ance

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

2,0

200 250 300 350 400 450 500 550 600

Wavelength / nm

Ab

sorb

ance

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1,0

200 250 300 350 400 450 500 550 600

Wavelength / nm

Ab

sorb

ance

Fig. 2 – Spectra of azo dyes: (I) MO, 2,0x10-5 M; (II) AO7, 4,0x10-5 M; (III) AO8, 4,0x10-5 M; (IV) AR151, 1,3 x10-5 M

At intermediate pH values, the equilibrium between the two species can be reached and the correspondent acidity constant was evaluated from the absorbances measured at different pH [2]. For MO, three assays were performed and pKa = 3.61±0.20 (SD, standard deviation). The values found in the literature lie between 3.38 and 4.46. From the AO7 spectra (fig. 2, II), it can be observed that the protonated species (yellow) remains stable until the pH of the solution reaches values close to 11. Above this value, the ionization takes place and the azo bond and the naphtol group seem to give rise to a different structure (red colour). The respective acidity constant was determined from measurements at four different pH values: pKa = 11.21±0.14 (SD). Oakes and Gratton refer that pka=11.4 [5]. AO8 dye (fig. 2, III) reveals a similar behaviour to that observed for AO7, except there is a decrease in its concentration at pH ≈ 1. This is possibly due to some aggregation in this ionic medium. The respective pKa was evaluated from four determinations at different pH: pKa = 11.57±0.17 (SD). As illustrated in (fig. 2, IV), for the diazo dye, AR151, it was not possible to identify an acid-base equilibrium by varying the pH of the solutions. At very low pH, precipitation took place with decolourization. In the basic region, more than one chemical species seem to be present and no isobestic point was observed. Conclusions From this work, it can be concluded that the three monoazo dyes, MO, AO7 and AO8 exhibit acid-base properties, with modification of their molecular structures. MO protonates in acidic medium, as already described in the literature [4] and the other two, AO7 and AO8, dissociate only at very high pH. For the diazo dye, AR151, an acid-base equilibrium was not observed in these experimental conditions. References 1. Zollinger, H., Color Chemistry – Synthesis, Properties

and Applications of Organic Pigments, Third revised edition, Wiley- VCH, Weinheim, 2003

2. Albert, A., Serjeant, E.P., The Determination of Ionization Constants – A Laboratory Manual, Third Edition, Chapman and Hall, New York, 1984

3. Perrin, D.D., Dempsey, B., Buffers for pH Control and Metal Ion Control, New York, 1979

4. Oakes, J., Gratton, J. Chem. Soc., Perkin Trans. 2, 2563-2568, 1998

5. Oakes, J., Gratton, J. Chem. Soc., Perkin Trans. 2, 1857-1864, 1998

Acknowledgements The authors are grateful for the financial support from the Research Unit of Textile and Paper Materials, Fundação para a Ciência e Tecnologia (FCT), Portugal.

(II)

(I)

(III)

(IV)

71

Development of coated conductive textile materials through in-situ polypyrrole polimerization

M. Pires, J. Lucas, M. Magrinho, R. Miguel, I. Trindade and M. Santos Silva Textile Department, Textile and Paper Materials R&D Unit, University of Beira Interior

Abstract In the present work, the aim was to study the application of polypyrrole as a conductive polymer on a cotton/polyester (50/50) fabric. For this, a conductive surface was developed using as a process to obtain the polymer, the chemical polymerisation carried out on the substrate surface, after being laid down on it the corresponding monomer by direct coating. Since it was not possible to achieve an very high solution viscosity for coating, this showing a high degree of substrate penetration, a second coating application using polyurethane polymer was done on both fabric sides, in order to assure the isolation of the conductive layer. The polypyrrole was synthesized using sodium dodecyl benzene sulphate (DBSS) as doping agent, combined with a polymeric additive, the polyethyleneglycol (PEG) and using as oxidizing agent the ammonium persulphate (APS). To conclude this work, the conductivity of treated substrates was evaluated, after tumble washing/drying, crease resistance, bending strength, sample deformation without breakage, steam pressing and ironing. Introduction Conducting polymers were discovered in the second half of the 70 (Faez et al., 2000). It was then discovered that the electrical conductivity of polyacetylene could be increased about 10 orders of magnitude by its oxidation with chlorine, bromine or iodine vapour, and this process, by analogy with the treatment of extrinsic semiconductors, was called "doping "(Rocha-Filho, 2000). The extrinsic conductivity is based on the introduction of a fixed number of impurity atoms in semiconductors, in which each atom replaces a semiconductor (Morris, 1982). The conductivity of the polymers takes place by simple chemical or electrochemical oxidation, with a number of anionic or cationic species simply called dopants (Chandrasekhar, 1999). There are several techniques for obtaining conductive textile substrates, highlighting the electrospinning, the inclusion of wires in the textile substrate and in-situ polymerization. The basis of this procedure is the adsorption of monomer and/or dopant and/or oxidant in the substrate until the chemical polymerization occurs (Chandrasekhar, 1999). Conducting polymers differ from typical organic polymers that are highly insulating, by the absence of electron π enabling electrical conductivity at room temperature. Examples include polyaniline, polypyrrole and polythiophene. Figure 1 shows the chemical structure of polypyrrole.

Figure 1. Chemical structure of polypyrrole

There is an energy difference between the orbital where electrons are that does not move (valence band) and the orbital in which electrons are relatively free (conduction band), this difference often called band-gap (Figure 2). When this difference is large (Eg = 10eV), it is difficult to excite electrons into the conduction band, as is the case of insulating materials. Conversely, if the difference is small, it is possible to excite electrons from the valence band to the conduction band by thermal excitation, vibration, or photons. The semiconductor structure of conducting polymers allows the electrical excitation or removal/addition of electrons, i.e., from the valence band to the conduction band, which is the most interesting property of these polymers. Moreover, a chemical oxidation essentially removes electrons from the valence band, being observed the presence of charges in the conducting polymer. These charges are delocalized over several monomer of the polymer, causing a relaxation of its geometry (now charged) to an energetically more favourable structure, conferring electrical conductivity to the polymer.

Figure 2. Band structure of a semiconductor material (www.chemistrydaily.com/chemistry/band_gap) Polymerization of polypyrrole starts by oxidation of a pyrrole monomer, which leads to the formation of an intermediate pyrrole cation-radical. Following, there is the linkage of two cation-radicals and, through a charge transfer occurs the elimination of two protons with the formation of a neutral dimmer. The dimmer is more easily oxidized than the monomer and thus is immediately converted into a new cation-radical. Thus, successively

72

wil be formed chains of oligomers, which in turn lead to the formation of polypyrrole. The doping process occurs with the oxidation of the polymer chain, which leads to the formation of a charged polycation that is balanced by the entry of a doping counter anion. In the case of polypyrrole, the oxidized form is conductive, while the reduced form hás insulating properties (Bruce 1997). For this polymer, the energy gap (Eg) between the valence and the conduction band in its reduced state is 3.2 eV, which means that it contains a very low electronic conductivity. The dopants are oxidizing or reducing chemicals that are usually embedded in a conducting polymer at the time of its synthesis. They can also be incorporated later by chemical, electrochemical or other means. The polypyrrole can become a conductor using as dopants dodecyl benzene sulphonate acid (DBSA) or naphthalene sulphonate acid (Lim et al, 2005) and in the presence of a polymeric additive, like poly (ethylene glycol) (PEG). Substrate coatings consist of applying a layer or film, or spreading materials of natural or synthetic origin in one or both sides of a substrate. The coating techniques have expanded in recent years and they have given rise to a new branch of industrial activity. Factors such as fashion and aesthetic change in dress habits, growth and development of textiles, the expansion of leisure and technological and economic reasons are the real incentives for the development of coatings in the textile apparel industry. Materials and Methods Initially, polypyrrole was applied in four fabrics of different composition: Polyester, Nylon, Wool and Cotton/Polyester. From the results obtained, the one which allowed better results was 50% cotton/50% polyester fabric. This study used this substrate, which presents the characteristics shown in Table 1.

Table 1. Characterization of substrate used in the study

Test Test standard Average value

Weight per surface

area unit EN 12127:1997 131 g/m2

Number of yarns per

cm EN 1049-2:1993

B= 31.5 yarns/cm

T= 30.7 yarns/cm

Yarn count NP 4105:1991 B = 1/30.1 Ne

T = 1/29.6 Ne

Composition NP 2248-1:2007 50.1% cotton

49.9% Polyester

The coating technique used to apply the polypyrrole on the substrate was the direct process of a multilayer coating. The equipment used for applying the coatings was the Laboratory Coating Device Type MATHIS VS. The equipment used for drying and curing was Ernest Benz AG oven, Type: KTF-M.

Chemical synthesis of polypyrrole solution to be used was based on the study "Synthesis and properties of soluble polypyrrole doped with dodecyl benzene sulphate combined with poly (ethylene glycol)" performed by Lim (Lim et al, 2005). Pyrrole monomer, ammonium persulfate as an oxidant, dodecyl benzene sodium sulphate as dopant and poly (ethylene glycol) as an additive that increases the solubility of pyrrole in the solution were used. These chemicals used are listed in Table 2.

Table 2. Chemical compounds use in the study

Compound Chemical formulae

Pyrrole C4H5N with purity degree higher than 97%, at 0,15 M

Dodecyl benzene sodium sulphate (DBSS)

CH3(CH2)11C6H4SO3Na, with purity degree of 80% aprox.

Poly (ethylene glycol) (PEG 1000)

H (OCH2CH2)n OH

Ammonium persulphate (NH4)2 S2O8

Sodium alginate Thickener / Stabilizing agent

Rioklen NF Detergent There have made several formulations for applying the solution of pyrrole to the substrate (solution 1). The solution which gave the best results of uniformity and conductivity on the substrate is presented in Table 3. Sodium alginate (a thickening agent) was used to increase the viscosity of the solution.

Table 3. Composition of solution 1

Pyrrole

(ml)

PEG 10000

(ml)

DBSS

(g) Sodium alginate (g)

1.2 10

(7g-10ml H2O) 1.2 0.01

The oxidation solution (solution 2) should be prepared first, due to low stability of the of pyrrole solution. According to the concentration of pyrrole of solution 1, the oxidation solution must contain 20% of ammonium persulphate (APS) in distilled water. After applying the solution onto the fabric by coating, the substrate is sprayed with the solution of ammonium persulphate, which causes the polymerization of pyrrole by oxidation. Then the substrate is dried in a laboratory oven at a temperature of 100 ° C for 1 minute, after a period of exposure to air from 15 to 30 minutes to give rise to polymerization of pyrrole. Before being applied the second coating, the substrate is still subjected to laundering (with 0.5 g/l Rioklen at 40°C for 10 minutes) and dried again at 100°C for 1 minute in order to eliminate excess polypyrrole deposited on the

73

surface of the substrate that would otherwise hinder the adhesion of the second coating. The second coat was as follows: 100 g Aktiprint HX 200 (resin), 5g Acramin F36 Blue 133%, 0.125g Antispumin DJ and 0.5g Mirox AM (thickener). With this formulation, a 0.1mm thick layer was applied, followed by a cure in the oven at 150°C for 5 minutes. As this study aims at the implementation of coating in smart clothing, 10 specimens were subjected to tests of wash/tumble drying, crease recovery, bending strength, deformation of the sample without breaking, pressing and steam ironing, whenever possible under the conditions described in the relevant standards (Table 4).

Table 4. Tests made to evaluate the performance of textile substrates coated with polypyrrole 5 washings/dryings NP EN 6330:2002 Crease recovery angle NP EN 22313:1993 Bending rigidity 20 successive bends in a

load/elongation tester Sample deformation without breakage

80% of breakage strength average in a load/elongation tester

Steam pressing IWS TM 290: 2000 Ironing 150ºC during 5 seconds

The treated and untreated surface of textile substrate was analyzed with SEM to observe the distribution of the conductive polymer. The apparatus Voltalab (potentiostat) was used in order to measure the changes of current intensity in samples with variation of applied potential. In the present study it was done the comparison of the conductivity for samples before and after undergoing the tests referred to above. Results and Discussion All graphs presented show the result of the average conductivity obtained on the samples tested, subjected to a potential 0 to 10 Volts. It appears that the results for the initial samples and subjected to a washing/drying exhibit almost constant values for different values of applied electric potential. In the case of 5 washing/drying, it was found that for some values of the samples showed no conductivity. This is explained by the application of polypyrrole has not enough fastness to repeated washings (Figure 3). However, these washes did not degrade the second coat. The conductivity values for the initial samples showed higher values than those subject to crease recovery test (Figure 4). This may be due to loss of continuity caused by polypyrrole coating crease. In a possible application of this study to clothing creases should be avoided since the loss of conductivity is the order of 0.010 S/m. The conductivity values for the initial samples showed values higher than those subjected to bending (Figure 5). This may be due to wear caused by polypyrrole coating subjected to 20 consecutive bending cycles. Also, the design process of clothes should avoid placing this coating in areas that are subjected to repeated bending

during wear (eg, elbows), since the loss of conductivity is the order of 0.10 S/m.

Figure 3. Conductivity of polypyrrole coated substrate before and after 1 and 5 washing/drying test.

Figure 4. Conductivity of polypyrrole coated substrate before and after crease recovery test.

Figure 5. Conductivity of polypyrrole coated substrate before and after bending rigidity test. The conductivity values for the initial samples showed higher values than those subjected to deformation, showing a loss of conductivity in the order of 0.04 S/m (Figure 6). This may be due to disruption of the continuity of the polypyrrole coating caused by specimen’s deformation. The applied strain is 80% of that of fracture, a very high value, which probably does not apply during wear of clothes. The conductivity values for the initial samples showed similar values to those subjected to steam press (Figure 7). The action of steam does not influence the conductivity of the samples. Thus, it can be concluded

74

that steam pressing is not a problem for the conductivity of the polypyrrole coated textiles.

Figure 6. Conductivity of polypyrrole coated substrate before and after deformation at 80% of breakage tensile strength test.

Figure 7. Conductivity of polypyrrole coated substrate before and after steam pressing test. The conductivity values for the initial samples are slightly higher (approximately 0.01S/ m) to those submitted to dry heat (Figure 8). Despite the fall in conductivity is not severe, other test conditions can be tried, including lower temperatures and iron with a protective fabric between clothes and iron.

Figure 7. Conductivity of polypyrrole coated substrate before and after ironing test. The SEM analysis shows the individual fibres of the textile substrate before and after application of polypyrrole. In Figure 8, in the images presented in the column "Sample with polypyrrole", there is still a fairly even distribution of clusters of polypyrrole which will be responsible for the conductivity of the treated substrates. Although these clusters appear to be on the surface, it is

assumed that they are linked to fibres, given that the sample was washed.

Fabric without treatment

Fabric with polypyrrole

Final fabric (after wash)

Figure 8. SEM images of fabric samples with and without polypyrrole (1000x)

Conclusions The results confirm the effectiveness of the method of polymerization of pyrrole in a cotton/polyester (50/50) fabric. The tests carried out during the study confirm the feasibility of the proposal, making the polypyrrole a potential candidate for application in smart clothing. For the application of conductive polymers in clothing, will be necessary to develop a method of protection of contacts, since these are subjected to wear and maintenance, for this reason may present significant loss of conductivity which will impair functionality. References 1. Bruce, 1997, “Chemistry of Solid State Materials 5:

Solid State Electrochemistry”, Cambridge University Press, Cambridge.

2. Chandrasekhar, Prasanna, 1999, Conducting Polymers, Fundamentals and Applications Kluwer Academic Publishers.

3. Faez, R. et al., 2000, M.-A. Polímeros condutores. Química Nova na Escola, n. 11, p. 13-18, 2000.

4. Lim, H. K., Lee S. O., Song K. J., Kim S. J. and. Kim K. H., 2005, “Synthesis and Properties of Soluble Polypirrolrrole Doped with Dodecylbenesulfonate and Combined with Polymeric Additive Poly(ethylene glycol)” Journal of applied Polymer Science, vol. 97, pp 1170-1175.

5. Rocha-Filho, Romeu C., 2000, Nobel 2000: Polímeros Condutores: Descoberta e Aplicações, Revista Atualidades em Química Nº12, Nov 2000.

6. www.chemistrydaily.com, 3-March-2008, 23:53. Acknowledgements To the technicians of Textile Department Mr. Filipe Santarém and Mr. José Machado, for their availability and assistance during laboratory work. To Eng. Ana Gomes from the Center for Optics of UBI, for her cooperation in SEM analysis of samples. To CITEVE, in the person of Eng. Angela Mendes for the availability of laboratory equipment and carry out of several performance tests.

75

Novel strategy of oxide type electrodes preparation for electrolytic treatment technologies

S. Sério 1, G. Martins2, M.E. Melo Jorge 2, Y. Nunes1, M. I. S. Pereira2, M. J. Pacheco3, L. Ciríaco3, A. Lopes3 1 CEFITEC, Dep. Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, 2 Dep. Química e Bioquímica/Centro de Ciências Moleculares e Materiais, FCUL, C. Grande C8, 1749-016 Lisboa, Portugal,

3 Dep. Química, UMTP, Universidade da Beira Interior, 6201-001 Covilhã, Portugal Abstract WO3 and PbOx thin films have been deposited on unheated glass and conductive glass (F-doped tin oxide (Sn02:F)) substrates by DC-reactive magnetron sputtering. The structures, morphologies and optical properties of both oxide systems films were studied by X-ray diffraction, field emission scanning electron microscopy and UV–Vis spectroscopy. Different %O2 were tested in both cases and in general the films exhibit good adhesion to the substrates. Introduction The electrochemical processes are suitable methods for the elimination of different kind of pollutants, besides being environmental friendly [1, 2]. Depending on the nature of the organic contaminants, electrochemical oxidation or reduction can be applied. Different materials can be used as electrodes, namely electrocatalytical materials like PbO2, boron doped diamond electrode (BDD) and WO3 [3-6]. However, the implementation of these methods has two main important issues to be considered. The efficiency of the material as a catalyst in the electrochemical process, which is measured by the extension of the degradation reaction and the ability to promote total mineralization or just partial degradation with the formation of more oxidized compounds. On the other hand, the efficiency of the material as electrode, including its cost, electrochemical stability, durability and energetic consumption has to be taken into account. To overcome these problems the electrodes preparation by DC-magnetron sputtering technique looks like a promising alternative. The main advantages are (1) high deposition rates, (2) ease of sputtering any metal, alloy or compound, (3) high-purity films, (4) extremely high adhesion of films, (5) excellent coverage of steps and small features, (6) ability to coat heat-sensitive substrates, (7) ease of automation and (8) excellent uniformity on large-area substrates [7]. In this context we have undertaken the preparation of oxide type electrodes by DC-magnetron sputtering. This work reports some preliminary results of the preparation and structural characterization of tungsten and lead oxides electrodes by DC- magnetron sputtering. Materials and Methods Tungsten and lead oxides films were deposited by DC-reactive magnetron sputtering on glass and conductive glass (F-doped tin oxide (Sn02:F)) substrates at room temperature in a custom made system, using a metallic lead disc (99.99% purity) and a tungsten disc (99.99% purity) as sputtering target, respectively.

The gases in the system were 99.99% pure Ar and O2 and partial pressures of these gases were separately controlled by mass flow controllers. Prior to the deposition, the substrates were cleaned successively in acetone, isopropanol and deionized water for 5 min each step and dried with nitrogen gas to remove any organic contamination. A diffusion pump was used to achieve a base pressure of 10-4 Pa (before introducing the gas mixture). Before the sputter-deposition step of the films, a movable shutter was interposed between the target and the substrates, and the target was pre-sputtered in Ar atmosphere for 5 min to clean the target surface. The target-to-substrate distance was kept constant at 100 mm. In the case of the tungsten oxide films, the total pressure, PT, during all depositions processes was kept constant at 1.6 Pa. The partial pressure of oxygen was set at 0.48 and 1.6 Pa (30% and 100% of PT). The sputtering power was kept at 220 W and the deposition times were 80 min. For the lead oxide films, the total pressure, PT, during all depositions processes was kept constant at 0.8 Pa. The partial pressure of oxygen was set at 0.24 Pa (30% of PT). The sputtering power was kept at 100 W and the deposition times were 30 min. The structural characterization of the films was carried out by X-ray diffraction (XRD) on a Philips Analytical PW 3050/60 X’Pert PRO (theta/2 theta) equipped with X’Celerator detector and with automatic data acquisition (X’Pert Data Collector (v2.0b) software), using a monochromatized CuKα radiation as incident beam, 40 kV–30 mA. Diffractograms were obtained by continuous scanning in a 2θ-range of 10º to 70º with a 2θ-step size of 0.02º and a scan step time of 20 s. The surface morphology of the films was examined by scanning electron microscope a Hitachi (S-2700)/Oxford (60–74). The optical properties of the films were measured with Shimadzu UV b - 2101PC UV/VIS spectrophotometer at room temperature within the wavelength range 300-900 nm. Results and Discussion For the as-prepared tungsten oxides the structural characterization shows an amorphous nature. In order to allow the crystalline growth, the films were thermal annealed at 400ºC in air during 2h. The XRD data, for the annealed tungsten oxides films deposited on glass and conductive glass (F-doped tin oxide (Sn02: F)) substrates, are presented in Figures 1 and 2, respectively.

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Figure 1 XRD patterns of the annealed WO3 films deposited on glass substrates at 30 and 100 % O2 in Ar/O2 mixture and P = 220 W.

Figure 2 XRD patterns of the annealed WO3 films deposited on conductive glass substrates (F-doped tin oxide (Sn02:F)) at 30 and 100 % O2 in Ar/O2 mixture and P = 220 W. The patterns show relative sharp peaks indicating the coalescence of the nanocrystalline phase WO3. According to the phase diagram [8], the structure evolution for this chemical composition should be as follows: monoclinic from room temperature up to 330 °C, orthorhombic between 330 and 740 °C and, finally, a tetragonal structure up to 1230 °C. Earlier studies show that the diffraction pattern features can indicate a mixture of the orthorhombic and the monoclinic room temperature WO3 phases [9]. The intensity of (0 0 2), (0 2 0) and (2 0 0) reflections at 2θ around 25º vary between the samples. This may be due to different fractions of orthorhombic and monoclinic phases, but can also arise from preferred orientation or from the presence of crystallographic shear planes [10]. It can also be observed for the sample obtained with 100% O2, in the sputtering process, two reflections at 2θ ≈14º and 28º which are not present in any of the other samples and most probably corresponds to another phase, not yet identified. The surface morphology of the annealed WO3 films were investigated by SEM as presented in Figure 3 for WO3 films deposited at 30 % O2 in Ar/O2 mixture. It is visible

that the surface morphology is influenced by the substrate type.

Figure 3 SEM images of the surface of annealed WO3 deposited with 30% O2 in Ar/O2 mixture and P = 220 W (magnification ×10000) a) in glass substrate and b) in conductive glass substrate (F-doped tin oxide (Sn02:F)). Figure 4 shows the optical transmittance spectra of WO3 thin films deposited on glass substrates at 30 and 100 % O2 in Ar/O2 mixture and P = 220 W. The films are semi-transparent in the visible region with more than 60% transmittance. The spectral transmittance increases with increase in the %O2. The optical band-gap of these films were determined from the transmission spectra using Tauc’s relation [11], given as

( )mgphotphot EEα E −= (1)

where, ( )/λE E photphot 1239= is the excitation energy

(in eV), with the wavelength λ in nanometers and m is a parameter accounting for the different band-gap transition modes, gE is the optical energy band-gap, and α is the

absorption coefficient (in cm−1), which is obtained near the absorption edge from the transmittance, T, using the equation

⎟⎠

⎞⎜⎝

⎛=

−

T dα

1ln1 (2)

where d is the thickness of the film [12]. In Eq. (1), the exponent m depends upon the type of optical transitions in the material. For indirect transitions, which is the case for WO3 film, the exponent takes the value [11], m = 2. Thus, the optical energy band-gap of WO3 films deposited on glass substrates at 30 and 100 % O2 in Ar/O2 mixture was

77

determined by plotting ( photE α ) versus the incident

photon energy ( photE ), as shown in Fig. 5.

300 400 500 600 700 800 900 10000

20

40

60

80

100

30 % O2

100 % O2

λ /nm

Tra

nsm

ittan

ce /%

Figure 4 Optical transmittance spectra of the annealed WO3 films deposited on glass substrates at 30 and 100 % O2 in Ar/O2 mixture and P = 220 W.

2.4 2.6 2.8 3.0 3.2 3.4 3.60

100

200

300

400

500

Photon energy, hυ /eV

(αE

phot)1/

2 /cm

-1/2eV

1/2

30 % O2

100 % O2

Figure 5 Plots of (αEphot)1/2 vs. photon energy for the

annealed WO3 films deposited on glass substrates at 30 and 100 % O2 in Ar/O2 mixture and P = 220 W. Straight lines are the corresponding extrapolations which allow the determination of gE .

It can be observed, that the optical energy band-gap was determined to be 2.87 eV for the film deposited with 30% O2, whereas the optical energy band-gap for the film obtained with a pure oxygen discharge comes out to be 2.78 eV. These values are in agreement with the published results for WO3 [13]. In the case of the lead oxide system the XRD shows that the as-sputtered films already present a crystalline structure as it can be observed in Figure 6a), for the sample obtained with 30% O2 and with the diffractions peaks compatible with a majority PbOx-type phase [14, 15]. However since we were interested in preparing PbO2 phase electrodes, several annealings were performed in air

at T = 100 and 300 ºC. All the attempts improved the crystallinity, but the phase remains the same (figure 6 b).

Figure 6 XRD patterns of the as-prepared (a) and annealed (b) PbOx films deposited on glass substrates with 30% O2 in Ar/O2 mixture and P = 100 W

The surface morphology of the annealed PbOx film was investigated by SEM as presented in Figure 7. The SEM micrographs of the film show a surface morphology characterized by relatively dense-packed surface particles resembling an array of different polygons. It can also be detected some agglomerates of particles distributed over the surface with average sizes of 7-8 μm.

Figure 7 SEM images of the surface of annealed PbOx deposited on glass substrates with 30% O2 in Ar/O2 mixture and P = 100 W a) magnification ×2000 and b) magnification ×4000.

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Another attempt to obtain the PbO2 phase, was done by an electrochemical treatment of the PbOx films namely the oxidation of PbOx phases. In the literature, these treatments are done in high acidic medium in order to generate β-PbO2 [16] or in high alkaline medium to obtain α-PbO2 [17]. These conditions were tested but the PbOx films dissolved when were immersed in both mediums. To overcome this problem, it was used a borax buffer solution (pH=9.2) and applied different current density values: (1) 25 μA cm-2 during 1 hour, (2) 0.2 mA cm-2 at a sweep rate of 0.28 μA /s and finally (3) 0.2 mA cm-2

during 5 h [18]. After this treatment XRD was done and it was revealed that the initial phases remain even after this procedure. In a future work we intend to deposit lead oxide in a conductive substrate and if the PbO2 phase is not achieved this electrochemical treatment will be applied. Conclusions WO3 and PbOx thin films grown with different oxygen partial pressures were deposited on unheated glass and conductive glass (F-doped tin oxide (Sn02:F)) substrates by DC-reactive magnetron sputtering. Different %O2 were tested in both cases and in general the films exhibit good adherence to the substrates and high mechanic stability. The as-sputtered WOx films are amorphous and the annealing leads to a crystalline growth which corresponds to a mixture of the orthorhombic and the monoclinic room temperature WO3 phases. In the case of the PbOx system the structural characterization revealed that the as-sputtered PbOx already presents a crystalline structure with the diffractions peaks compatible with a main phase of PbO-type. References 1. Martínez-Huitle, C.A. and Ferro, S., Chem. Soc. Rev.,

35, 1324, 2006. 2. Simonsson, D., Chem. Soc. Rev., 26, 181, 1997. 3. Ciríaco, L., Anjo, C., Correia, J. Pacheco, M.J. and

Lopes, A., Electrochim. Acta, 54, 1464, 2009.

4. Weiss, E., Groenen-Serrano, K. and Savall, A., J. Appl. Electrochem., 38, 329, 2008.

5. Carvalho, C., Fernandes, A., Lopes, A., Pinheiro, H. and Gonçalves, I., Chemosphere, 67, 1316, 2007.

6. Habazaki, H., Hayashi, Y. and Konno, H., Electrochim. Acta, 47, 4181, 2002.

7. Swann, S., Phys. Technol., 19, 67, 1988. 8. Naidu, S.V.N. and Rao, P.R., Phase Diagrams of

Binary Tungsten Alloys, Indian Institute of Metals, Calcutta, 1991.

9. Marsen, B., Cole, B. and Miller, E.L., Sol. Energy Mater. Sol. Cells, 91, 1954, 2007.

10. Jimenez, I., Arbiol, J., Dezanneau, G., Cornet, A. and Morante, J.R., Sens. Actuators, B, 93, 475, 2003.

11. Tauc, J., Amorphous and Liquid Semiconductors, Plenum, London, 1974.

12. Mardare, D., Tasca, M., Delibas, M. and Rusu, G. I., Appl. Surf. Sci., 156, 200, 2000.

13. González-Borrero, P. P., Sato, F., Medina, A. N., Baesso, M. L., Bento, A. C., Baldissera, G., Persson, C., Niklasson, G. A., Granqvist, C. G. and Ferreira da Silva, A., Appl. Phys. Lett., 96, 061909, 2010.

14. Venkataraj, S., Kappertz, O., Drese, R., Liesch, Ch., Jayavel R. and Wuttig, M., Phys. Status Solidi. A, 194, 192, 2002.

15. Venkataraj, S., Kappertz, O., Drese, R., Liesch, Ch., Jayavel, R. and Wuttig, M., J. Vac. Sci. Technol., A, 19, 2870, 2001.

16. Andrade, L.S., Rocha-Filho, R.C., Bocchi, N. And Biaggio, S.R., Quim. Nova, 27, 866, 2004.

17. .Hueta, F., Musiani, M. and Nogueira, R. P., Electrochim. Acta, 48, 3981, 2003.

18. Laurindo, E.A., Bocchi, N. and Rocha-Filho, R.C., J. Braz. Chem. Soc, 11, 429, 2000.

Acknowledgements This work was supported by FCT (Fundação para a Ciência e Tecnologia) under contract no. PTDC/AAC-AMB/103112/2008.

79

Optimization of a diluted alkaline pretreatment of rock-rose to produce bioethanol P. Baptista1, N. Gil1, M. E. Amaral 1, A. P. Duarte 1

1Research unit of Textile & Paper Materials, University of Beira Interior, 6201-001 Covilhã, Portugal Abstract Lignocellulosic materials are an alternative source for ethanol production. Citus Ladanifer (rock-rose) is a shrubby species abundant in temperate zones and is available as forest residue. In the bioconversion of lignocellulosic materials into ethanol is essential the pre-treatment of the material prior to enzymatic hydrolysis in order to obtain high yields of sugars and consequently high yields of ethanol. In this study, it was evaluated the effect of particle size, reaction temperature, residence time and alkaline concentration on the amount of released total reducing sugars, removed lignin and resulting recovered solids of alkaline pretreatment of Cistus ladanifer. Each sample was treated according to different operating conditions and Response Surface Methodology (RSM) was used for the purpose of modelling the yield of total reducing sugars, removed lignin and recovered solids. The maximum removal of reducing sugars was 171,6 mg / g for the particle size of 2 mm, with reactions performed at 180 ° C for 22,5 minutes with 0,1% sodium hydroxide. The maximum removal of lignin was 448,7 mg / g for the particle size of 6 mm, with reactions performed at 160 ° C for 15 minutes with 6,0% sodium hydroxide. The minimum solids recovered was 208,5 mg / g for the particle size of 2 mm, with reactions carried out at 200 ° C for 30 minutes with 6,0% sodium hydroxide. Introduction The lignocellulosic biomass represents a large potential feedstock for ethanol production. The low cost and availability of a wide range of lignocellulosic materials [1] offer many possibilities for the development of biomanufacturing [2]. The developing of alternative resources to fossil fuels like biofuels from lignocellulosic materials is especially relevant in Portugal, where the forest covers around 38,4% of the territory, which represent a source of large amounts of forestry biomass residues (pruning) and shrub species that can be used as raw material for bioethanol production [3]. The use of these residues in bioprocesses is environmentally favourable, considering that the problem of their disposal can be solved. Ethanol from renewable resources has been of interest in recent decades as an alternative fuel or oxygenate additive to the current fossil fuels. The usual renewable raw materials used in bioethanol production are corn grain and sugar cane, which supply can be limited in near future. Therefore lignocellulosic biomass is seen as an attractive feedstock for ethanol production in the future [4,5]. Lignocellulosic materials are renewable resources that can be directly or indirectly used for the production of biomolecules and commodity chemicals. However, the industrial utilization of these materials has been compromised by several factors such as the close

association that exists among the three main components of the plant cell wall, cellulose, hemicelluloses and lignin, and the low efficiency by which lignocellulosic substrates are converted through biological processes [6]. Alkaline pretreatment is based on the effect of the addition of dilute bases on the biomass: increase of internal surface by swelling, decrease of polymerization degree and crystallinity, destruction of links between lignin and other polymers, and breakdown of lignin [2]. An important aspect of alkali pretreatment is that the biomass on itself consumes some of the alkali. The residual alkali concentration after the alkali consumption by the biomass is the alkali concentration left over for the reaction. Alkali extraction can also cause solubilisation, redistribution and condensation of lignin and modifications in the crystalline state of the cellulose. These effects can lower or counteract the positive effects of lignin removal and cellulose swelling. Another important aspect of alkaline pretreatment is the change of the cellulose structure to a form that is denser and thermodynamically more stable than the native cellulose [7]. The biodegradability of lignocellulosic biomass is limited by several factors, such as crystallinity of cellulose, the surface area available, and lignin content. The pre-treatments have an effect on one or more of these factors [8], in the case of alkaline pretreatment, it has a positive effect on the accessible surface area, in the structure of lignin degradation and it does not give rise to furfural and 5-hidroxymethylfurfural production [7]. The aim of this research was to determine the effect of alkaline concentration, temperature, residence time and particle size, on the release of total reducing sugars, removed lignin and resulting recovered solids on alkaline pretreatment of Cistus ladanifer. In order to evaluate the behavior of these variables, process optimization was followed using RSM with central composite as statistical design. Materials and Methods The shrubs were harvested in May 2007 and stored at room temperature during two months. After this time they were stored in closed plastic bags. The plant consisted of stalks and leaves and was milled in a cutting mill (Retsch Mühle) and screened in a mechanical sieve shaker (Test Sieve – 5657 HAAN) following the Standard Biomass Analytical Procedures of National Renewable Energy Laboratory [9]. The feedstock for the pretreatment was milled and screened to a particle size between 0,180 - 2 mm and 0,180 – 6 mm. Alkaline pretreatments were carried out in 200mL steel reactors immersed in a heating PEG 400 bath with agitation and controlled temperature systems. Whole plant samples (10g, oven dry) were treated with diluted sodium hydroxide under different

80

reaction conditions according to the central composite rotatable design, generated using Design Expert® software version 7.1.5 from Statease, Inc., Minneapolis, USA. After reaction was completed, solids were separated from aqueous solution by filtration. The pretreatment was carried out at temperatures between 160 and 200 °C, the reaction times ranged from 15 to 30 minutes and the alkali charge used in the pretreatment ranged between 1.6 and 6% (w / w). To determine the insoluble lignin, the pH of the liquid fraction was reduced to pH 2, left to stand for 24 h at 4 °C, and then centrifuged for 5 minutes at a speed of 4500 rpm and finally put in an oven at 105 ºC, for 24 hours to remove any traces of water. The dry lignin is then weighed. The total reducing sugars were analyzed by the 2,4-dinitrosalycilic acid (DNS) method, known as Miller method [10]. The recovered solids were dried and weighed. Results and Discussion Reducing sugars According to data from table 1, it was found that independently the particle size, the use of reducing sugars as a response to alkaline pretreatment does not model the values obtained, considering that the correlation coefficient (R2) are lower than to 0,6, which means that the points did not fit the model.

Table 1- ANOVA table for the adjusted model of total reducing sugars for each particle size.

Particle Size (mm) Source Sum of

Squares Mean

Square F

Value p-value

(Prob > F)

Model 8365,53 4182,76 9,03 0,0021

C-Charge 3671,97 3671,97 7,92 0,0119

C2 4693,55 4693,55 10,13 0,0054

Residual 7877,76 463,40 - -

Lack of Fit 7836,66 653,06 79,45 < 0,0001

Pure Error 41,10 8,22 - -

Total 16243,29 - - -

R2 0,5150 - - -

2

R2 (adjusted) 0,4580 - - -

Model 5865,54 2932,77 7,39 0,0049

C- Charge 1609,61 1609,61 4,06 0,0601

C2 4255,93 4255,93 10,72 0,0045

Residual 6746,18 396,83 - -

Lack of Fit 6669,14 555,76 36,07 0,0005

Pure Error 77,04 15,41 - -

Total 12611,72 - - -

R2 0,4651 - - -

6

R2 (adjusted) 0,4022 - - -

Removed lignin Table 2 shows the response model for removed lignin in the case of a particle size of 2 mm. As it can be seen, the polynomial model defined for the response has meaning for a significance level of 0.01%. The model also presents a correlation coefficient (R2) of 0,8353, showing that 83,53% of the measured points fit the model.

Table 2- ANOVA table for the adjusted model of removed lignin for particle size of 2 mm.

Source Sum of Squares Mean Square F Value p-value (Prob > F)

Model 141943,55 28388,71 14,20 < 0,0001

A-Temperature 5511,67 5511,67 2,76 0,1190

C- Charge 71679,77 71679,77 35,86 < 0,0001

AC 16227,01 16227,01 8,12 0,0129

A2 18435,84 18435,84 9,22 0,0089

C2 34231,58 34231,58 17,12 0,0010

Residual 27986,71 1999,05 - -

Lack of Fit 27230,39 3025,60 20,00 0,0021

Pure Error 756,32 151,26 - -

Total 169930,26 - - -

R2 = 0,8353; R2 (adjusted) = 0,7765 The final equation adjusted to the response of the removed lignin is as follows:

Figure 1 shows the interaction effect between temperature and alkali charge that most influence the response.

Figure 1. Response surface plots of the central composite design for the optimization of the alkaline pretreatment. Effect of alkali charge (%) and temperature (ºC). Other factors were constant at zero levels. According to the outcome for the modeling of removed lignin from the alkaline pretreatment for a particle size of 2 mm, it can be said that the factor which influences the result is the alkali charge, followed by temperature. For a particle size of 6 mm, the polynomial model defined for the response has meaning for a significance level of

81

0.01%. The model also presents a correlation coefficient (R2) of 0,8446, showing that 84,46% of the measured points fit the model.

Table 3- ANOVA table for the adjusted model of removed lignin for particle size of 6 mm.

Source Sum of Squares

Mean Square

F Value

p-value (Prob > F)

Model 158257,61 31651,52 15,22 < 0,0001

A-Temperature 1252,81 1252,81 0,60 0,4506

C-Charge 76596,71 76596,71 36,82 < 0,0001

AC 36356,91 36356,91 17,48 0,0009

A2 21858,26 21858,26 10,51 0,0059

C2 26152,76 26152,76 12,57 0,0032

Residual 29122,56 2080,18 - -

Lack of Fit 28713,90 3190,43 39,04 0,0004

Pure Error 408,66 81,73 - -

Total 187380,17 - - -

R2 = 0,8446; R2 (adjusted) = 0,7891 The final equation adjusted to the response of the removed lignin is as follows:

Figure 2 shows the surface response for the modeling of removed lignin for a particle size of 6 mm and it can be said that, the behavior is identical to the particle size of 2 mm.

Figure 2 Response surface plots of the central composite design for the optimization of the alkaline pretreatment. Effect of alkali charge (%) and temperature (ºC). Other factors were constant at zero levels. Recovered solids In accordance with data from Table 4, the model presents a correlation coefficient (R2) of 0,9613, showing that 96,13% of the measured points fit the model and a significance level of 0.01%.

Table 4- ANOVA table for the adjusted model of recovered solids for particle size of 2 mm.


Mean Square

F Value

p-value (Prob > F)

Model 278119,38 69529,85 93,04 < 0,0001

A-Temperature 56592,56 56592,56 75,72 < 0,0001

C-Charge 191492,73 191492,73 256,23 < 0,0001

AC 6044,50 6044,50 8,09 0,0123

C2 23989,59 23989,59 32,10 < 0,0001

Residual 11210,20 747,35 - -

Lack of Fit 10868,30 1086,83 15,89 0,0035

Pure Error 341,91 68,38 - -

Total 289329,59 - - -

R2 = 0,9613; R2 (adjusted) = 0,9509 The final equation adjusted to the response of the recovered solids is as follows:

In Figure 3 the modeling of recovered solids of the alkaline pretreatment of the rock rose for a particle size of 2 mm, shows that the factor which influences the result is the alkali charge, followed by temperature.

Figure 3. Response surface plots of the central composite design for the optimization of the alkaline pretreatment. Effect of alkali charge (%) and temperature (ºC). Other factors were constant at zero levels. In Table 5 it can be analyzed the information related with the pretreatments forparticle size of 6 mm, corresponding to the analysis of variance (ANOVA) for response model showing a correlation coefficient (R2) of 0,9830, which shows that 98,30% of the measured points fit the model. The polynomial model for the definitive response has meaning for a significance level of 0.01%.

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Table 5- ANOVA table for the adjusted model of recovered solids for particle size of 6 mm.


Mean Square

F Value

p-value (Prob > F)

Model 272399,82 90799,94 308,97 < 0,0001

A-Temperature 94030,85 94030,85 319,96 < 0,0001

C-Charge 161505,66 161505,66 549,56 < 0,0001

C2 16863,31 16863,31 57,38 < 0,0001

Residual 4702,07 293,88 - -

Lack of Fit 4464,37 405,85 8,54 0,0141

Pure Error 237,70 47,54 - -

Total 277101,89 - - -

R2 = 0,9830; R2 (adjusted) = 0,9798 The final equation adjusted to the response of the recovered solids is as follows:

This equation shows that no significant interaction between variables, however, one can say that the most important factor is the alkali charge, because it appears as a quadratic term. Conclusions The alkali charge and temperature are factors of great importance in the removal of lignin as well as in the amount of recovered solids. In the case of the removal of lignin, it appears that there is a regression of this removal format temperatures above 160 °C this, for solids recovering, higher temperatures give rise to lower recoveries. Actually, the temperature factor is very important in the performance of an alkaline pretreatment, considering that the components of biomass are very reactive when subjected to high temperatures in an alkaline medium. Empirical quadratic models obtained with high significance for the removal of lignin can be used to develop the optimization of bioethanol production from this type of biomass. These models allow knowing the influence of each variable in the pretreatment and the supremacy of that influence. Thus, temperature and alkaline charge were the variables that showed more influence, for the two particles sizes pretreated in this work, allowing an optimization process. References [1] Cara, C., Ruiz, E., Oliva, J.M., Sáez, F., and Castro, E., Bioresource Technology, 99, 1839, 2008; [2] Sánchez, O.J. and Cardona, C.A., Bioresource Technology, 99, 5270, 2008; [3] Gil, N., Ferreira, S., Amaral, M.E., Domingues, F.C., Duarte, A.P., Industrial Crops and Production, 32, 29, 2010; [4] McKendry, P., Bioresource Technology, 83, 37, 2002;

[5] Galbe, M. and Zacchi, G. Appl. Microbiology Biotechnology, 59, 618, 2002; [6] Emmel, A., Mathias, A.L., Wypych, F., and Ramos, L.P., Bioresource Technology, 86, 105, 2003; [7] Hendriks, A.T.W.M., and G. Zeeman, G., Bioresource Technology, 100, 10, 2009; [8] Kumar, P., Barrett, D. M., Delwiche, M. J., and Stroeve, P., Industrial & Engineering Chemistry Research 48, 3713, 2009; [9] NREL, Standard Biomass Analytical Procedures, Laboratory Analytical Procedure National Renewable Energy Laboratory, Golden, CO, USA, 2008; [10] Miller, G.L., Analytical Chemistry 31, 426, 1959.

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Development of N-doped TiO2 thin films by DC reactive magnetron sputtering for photocatalytic applications

S. Sério 1, M.E. Melo Jorge 2, G. Martins2, M. J. P. Maneira1, Y. Nunes1 1 CEFITEC, Dep. Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, 2 Dep. Química e Bioquímica/Centro de Ciências Moleculares e Materiais, FCUL, C. Grande C8, 1749-016 Lisboa, Portugal

Abstract N-doped TiO2 thin films have been deposited on unheated glass substrates by DC- reactive magnetron sputtering. The structures and properties of the N-doped TiO2 films were studied by X-ray diffraction, field emission scanning electron microscopy and UV–Vis spectroscopy. The doping of nitrogen into TiO2 lattices leads to a smooth shift of the absorption band toward visible light regions. Introduction Photocatalysis with a semiconductor has recently emerged as an advanced oxidation process for environmental decontamination. It is safe, versatile, and consumes only light. The anatase phase of TiO2 has proven to be the most promising semiconductor photocatalyst for widespread environmental applications because it shows a high reactivity under ultraviolet (UV) light and it is nontoxic, stable and inert chemically [1, 2]. However, TiO2 only becomes active under irradiation with ultraviolet UV light whose energy exceeds the band gap of 3.2 eV in the anatase crystalline phase. This inhibits the utilization of solar light as a sustainable energy source for TiO2 activation because only 5 % of the incoming solar energy on the earth’s surface is in the UV range. Consequently, TiO2 photocatalysis is limited for its widespread applications by: (i) the need of photo-excitation energy beyond his bandgap, (ii) the low light utilization efficiency. The activation of TiO2 under visible light can allow the development of promising processes for the remediation of contaminated water resources using solar light. Earlier investigations show that doping with transition metals for example Fe, Ni, and Cr into TiO2, lead to a increase of the absorption of visible-light, but these doped materials suffer from thermal instability [3-6]. Recently, doping with non metal atoms such as N, S, and C [7, 8] into the TiO2 lattice were reported, and show that can shift the absorption edge to lower energies and increase the visible absorption. Among them, N-doped TiO2 (N–TiO2) has attracted considerable attention due to its effective photocatalytic activity in the visible region and was most widely studied. The visible light response of N-doped TiO2 was first discovered in 1986 by Sato [9]. The recent work by Asahi et al. [7] has renewed a great interest in N-doped TiO2 as a visible light photocatalyst. A variety of methods such as sputtering, ion implantation, chemical vapor deposition, sol–gel, oxidation of TiN, and decomposition of N-containing metal organic precursors have been utilized to prepare N–TiO2 [10–17]. Among them physical vapour deposition and especially reactive magnetron sputtering is an attractive way to deposit these films. A titanium target sputtered in a mixed working gas (O2 + N2) [18, 19] can

be used to modify N/O ratio in the films. Another advantage is to develop immobilized TiO2-based thin films instead of produce powder photocatalysts which are normally used in photodegradation studies. This work reports the effect of the nitrogen doping on the growth, microstructure, surface morphology and optical properties of TiO2 thin films deposited by DC reactive magnetron sputtering. Materials and Methods Nitrogen-doped TiO2 (TiO2-xNx) films were deposited by DC-reactive magnetron sputtering on glass substrates at room temperature in a custom made system. A titanium disc (99.99% purity) having 64.5 mm of diameter and 4 mm of thickness was used as sputtering target. The gases in the system were 99.99% pure Ar, O2 and N2, and partial pressures of these gases were separately controlled by mass flow controllers. Prior to the deposition, the glass substrates were cleaned successively in acetone, isopropanol and deionized water for 5 min each step and dried with nitrogen gas to remove any organic contamination. A diffusion pump was used to achieve a base pressure of 10-4 Pa (before introducing the gas mixture). The total pressure, PT, during all depositions processes was kept constant at 0.8 Pa. The partial pressure of nitrogen PN2 was varied between 0.008 and 0.04 Pa (i.e. 1, 2 and 5% of PT), while the partial pressure of oxygen was kept constant at 0.08 Pa (10% of PT). The sputtering power was kept at 1000 W. The deposition times were 80 min. Before the sputter-deposition step of the films, a movable shutter was interposed between the target and the substrates, and the target was pre-sputtered in Ar atmosphere for 5 min to clean the target surface. The target-to-substrate distance was kept constant at 100 mm. The as-sputtered films were thermal annealed in N2 atmosphere at 400 ºC for 4 h in a tubular furnace in order to improve crystalline growth. The structural characterization of the films was carried out by X-ray diffraction (XRD) on a Philips Analytical PW 3050/60 X’Pert PRO (theta/2 theta) equipped with X’Celerator detector and with automatic data acquisition (X’Pert Data Collector (v2.0b) software), using a monochromatized CuKα radiation as incident beam, 40 kV–30 mA. Diffractograms were obtained by continuous scanning in a 2θ-range of 20º to 70º with a 2θ-step size of 0.02º and a scan step time of 20 s. The average crystallite sizes of the films were calculated from the X-ray line broadening according to the Scherrer equation [20]. Correction for the line broadening by the instrument was applied using a large particle size silicon standard. The peak broadening analysis was applied to anatase (004) reflection.

84

The surface morphology and thickness of the films were examined by field-emission scanning electron microscope (FEG-SEM JEOL 7001F). In order to prevent charge build up a thin gold film was coated on the films during analysis. The optical properties of the films were measured with Shimadzu UV b - 2101PC UV/VIS spectrophotometer at room temperature within the wavelength range 300-900 nm. Results and Discussion Figure 1 shows the XRD patterns of the as-sputtered N-doped TiO2 films deposited for different nitrogen concentrations in a fixed oxygen percentage and sputtering pressure of 0.8 Pa, for 1000 W. It can be observed that the as-sputtered films are amorphous, although when % N2 = 5 the pattern display two diffraction peaks with (101) and (004) orientation at 2θ equal to 25 and 38º, respectively, typical of the anatase TiO2.

Figure 1 XRD patterns of the as-prepared N- doped TiO2 films deposited for a fixed oxygen percentage (10%) and at different percentage of nitrogen in Ar/O2/N2 mixture: a) 1% N2 b) 2% N2 and c) 5% N2. Since the as-deposited films were amorphous or poorly crystallized all the samples were thermal annealed at 400 ºC during 4 h in N2 atmosphere. The XRD data for the annealed TiO2 films are presented in Figure 2. The patterns (Figure 2) show relative sharp peaks indicating the coalescence of nanocrystalline anatase-phase TiO2. It can also be observed that the film obtained with 1 % of N2 exhibits a random orientation and for the films obtained with 2% and 5% N2 a preferential growth of the reflection (004) along the c axis is detected (Figure 2). Similar variations in the preferred orientation we have also observed in the growth of TiO2 films by DC- reactive magnetron sputtering [21]. The crystallite sizes show slightly differences between the annealed N-doped TiO2 films deposited at different percentage of nitrogen 1, 2 and 5% N2 in Ar/O2/N2 mixture, i.e., 36, 31 and 40 nm, respectively.

The effect of increasing the nitrogen partial pressure on the surface morphology of the N-doped TiO2 films deposited on glass substrates at 1000 W after annealing was investigated by SEM. Figures 3 shows SEM micrographs of the films for the different nitrogen percentages. The surface morphology of these films changes with the increase of the nitrogen in the discharge in agreement with the XRD data. It can be observed agglomeration of grains that lead to the formation of agglomerates or particulates which are formed by individual nano-phase grains that exhibit different dimensions. The surface morphologies of the films consist of submicrometer-sized grains (agglomerates of grains or particulates), with average sizes of 50–100 nm distributed over the substrate surface with a ‘blooming flower-like’ appearance and bigger agglomerates are observed for the film obtained with 5% N2 in the sputtering process. A more detailed observation of these images evidences the formation of the nanosized grains protruding on the submicrometer-sized grains. The nanosized grains result in an increase in active surface area and also promote the formation of porous N-doped TiO2 films that are very important for photocatalytic applications.

Figure 2 XRD patterns of the annealed N-doped TiO2 films deposited for a fixed oxygen percentage (10%) and at different percentage of nitrogen in Ar/O2/N2 mixture: a) 1% N2 b) 2% N2 and c) 5% N2 Figure 4 shows the optical transmittance spectra of the annealed N-doped TiO2 thin films grown on unheated glass substrates at different PN2. From this figure, it can be seen that the doping of nitrogen induces a smooth shift of absorption edge to the visible light region. An abrupt decrease of optical transmission with the decrease of the wavelength around 330-350 nm, which is observed for all the films, is caused by interband electron transitions in the N- doped TiO2 films.

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Figure 3 FE-SEM images of the annealed N- doped TiO2

films deposited for a fixed oxygen percentage (10%) and at different percentage of nitrogen in Ar/O2/N2 mixture: a) 1% N2 b) 2% N2 and c) 5% N2. The relationship between the absorption coefficient α and the transmittance (T) at short wavelengths close to the optical band gap is given by the following formula

(1)

where d is the thickness of the film [22]. Assuming that the N-doped TiO2 to be an indirect band gap

semiconductor, as is TiO2, the optical bang gap of the films can be determined by using Tauc approach [23]:

(2)

where α is the absorption coefficient (in cm−1),

( =1239/λ) is the excitation energy (in eV), with the wavelength λ in nanometers and m is a parameter accounting for the different band-gap transition modes (being m=1/2 for direct allowed transition, m=3/2 for direct forbidden, m=2 for indirect allowed and m=3 for indirect forbidden) [24]. The extrapolation of the

( ) product to zero value gives an absorption

energy (Figure 5) which corresponds to the band gap. The obtained results are summarized in Table 1.

300 400 500 600 700 800 900 10000

20

40

60

80

100

Tra

nsm

ittan

ce /%

λ /nm

10 % O2+ 1 % N

2

10 % O2+ 2 % N

2

10 % O2+ 5 % N

2

Figure 4 Optical transmittance spectra of the annealed N-doped TiO2 films deposited for a fixed oxygen percentage (10%) and at different percentage of nitrogen (1, 2 and 5% N2) in Ar/O2/N2 mixture.

2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.00

200

400

600

800

(αE

phot)1/

2 /cm

-1/2eV

1/2

Photon energy, hυ /eV

10 % O2+ 1 % N

2

10 % O2+ 2 % N

2

10 % O2+ 5 % N

2

Figure 5 Plots of (αEphot)1/2 vs. photon energy for the

annealed N-doped TiO2 thin films deposited for a fixed oxygen percentage (10%) and at different percentage of nitrogen (1, 2 and 5%N2) in Ar/O2/N2 mixture. Straight

86

lines are the corresponding extrapolations which allow the

determination of .

Table 1. Summary of the thicknesses (obtained from the

cross-sectional SEM images) and optical band gap ( ), of the annealed N-doped TiO2 films deposited for a fixed oxygen percentage (10%) and at different percentage of nitrogen (1, 2 and 5% N2) in Ar/O2/N2 mixture

sputtering power/ W

O2 % N2 %thickness

/nm /eV

1 525 3.28 10 2 790 3.19 1000

5 830 3.17

Upon increasing the partial pressure of nitrogen, the band

gap decreases. The band gap of the N-doped TiO2 thin film grown with 5% N2 in the discharge, is estimated to be about 3.17 eV, as shown in Fig. 5. Earlier studies have reported that N-doped TiO2 powders exhibited visible light absorption as a shoulder in the wavelength range of 400–600 nm and then suggested that the isolated N 2p narrow band formed above the O 2p valence was responsible for the visible light response [17]. In the present study, however, we observe a smooth shift of absorption edge to the visible light region, which implies that the narrowing of the band gap by doping nitrogen due to the mixture of N 2p and O 2p states occurs in our films [7]. Conclusions Nitrogen-doped TiO2 thin films grown with different nitrogen partial pressures were deposited on unheated glass substrates using DC reactive magnetron sputtering process. The transparent films gradually became yellowish upon increasing N content. UV–Vis spectroscopy measurements showed that the doping of nitrogen into TiO2 lattice induced a smooth shift of absorption edge to the visible light region and a decrease in the band gap. The band gap of the N-doped TiO2 thin film obtained with 5% of nitrogen in the discharge decreased to about 3.17 eV. References 1. Fujishima, A. and Honda, K., Nature, 238, 37, 1972. 2. Daude, N., Gout, C. and Jouanin, C., Phys. Rev.B, 15, 3229, 1997. 3. Klosek, S. and Raftery, D., J. Phys. Chem. B, 105, 2815, 2001. 4. Ghosh, A.K. and Maruska, H.P., J. Electrochem. Soc., 124, 1516, 1977. 5. Choi, W., Termin, A. and Hoffmann, M.R., J. Phys. Chem., 98, 13699, 1994. 6. Linsebigler, A.L., Lu, G.Q. and Yates, J.T., Chem. Rev., 95, 735, 1995. 7. Asahi, R., Morikawa, T., Ohwaki, T., Aoki, A. and Taga, Y., Science, 293, 269, 2001.

8. Khan, S., Al-Shahry, M. and Ingler, W.B., Science, 297, 2243, 2002. 9. Sato, S., Chem. Phys. Lett., 123, 126, 1986. 10. Sano, T., Negishi, N., Koike, K., Takeuchi, K. and Matsuzawa, S., J. Mater. Chem., 14, 380, 2004. 11. Tokudome, H. and Miyauchi, M., Chem. Lett., 33, 1108, 2004. 12. Yang, M., Yang, T. and Wong, M., Thin Solid Films 469, 1, 2004. 13. Kobayakawa, K., Murakami, Y. and Sato, Y.J., Photochem. Photobiol. A, 170, 177, 2004. 14. Diwald, O., Thompson, T.L., Goralski, G., Walck, S.D. and Yates Jr., J.T., J. Phys. Chem. B, 108, 52, 2004. 15. Morowetz, M., Balcerski, W., Colussi, A.J. and Hoffmann, M.R., J. Phys. Chem. B, 108, 17269, 2004. 16. Torres, G.R., Lindgern, T., Lu, J., Granqvist, C. and Lindquist, S., J. Phys. Chem. B, 108, 5995, 2004. 17. Irie, H., Watanabe, Y. and Hashimoto, K., J. Phys. Chem. B, 107, 5483, 2003. 18. Oyama, T., Ohsaki, H., Tachibana, Y., Hayashi, Y., Ono, Y. and Horie, N., Thin Solid Films, 351, 235, 1999. 19. Ianno, N.J., Enshashy, H. and Dillon, R.O., Surf. Coat. Technol., 155, 130, 2002. 20. Cullity, B. D., Elements of X-ray Diffraction, 2nd edition, Addison-Wesley, Reading, MA, 1978. 21. Sério, S., Melo Jorge, M.E., Maneira, M.J.P. and Nunes, Y., “Influence of O2 partial pressure on the growth of nanostructured anatase phase TiO2 thin films prepared by DC reactive magnetron sputtering”, submitted in Mater. Chem. Phys., (2010). 22. Mardare, D., Tasca, M., Delibas, M. and Rusu, G. I., Appl. Surf. Sci., 156, 200, 2000. 23. Tauc, J., Amorphous and Liquid Semiconductors, Plenum, London, 1974. 24. Eufinger, K, Poelman, P., Poelman, H., De Gryse, R. and Marin, G. B., J. Phys. D: Appl. Phys., 40, 5232, 2007. Acknowledgements The authors wish to acknowledge the FCT (Fundação para a Ciência e Tecnologia).

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POSTERS

89

Indocarbocyanines as New Ligands for Affinity Chromatography D. Almeida1, F. Sousa1, P. Almeida1, R. E. F. Boto1

1Health Sciences Research Center, University of Beira Interior, 6201-001 Covilhã, Portugal

Abstract Some derivatized indocarbocyanines were synthesized envisioning there use as new ligands for Affinity Chromatography. The introduction of groups in the 5 position of the indole nucleus present in both terminal of the cyanines dyes involves the previous reaction of p-substituted phenylhydrazine with 3-methylbutan-2-one by conventional Fisher indole synthesis obtaining the respective 2,3,3-trimethylindolenine substituted. Quaternary salts were obtained by reacting the so obtained 2,3,3-trimethylindolenines with 11-bromoundecanoic acid. Finally, the indocarbocyanine dyes were obtained from the condensating of the resulting quaternary salts with triethyl orthoformate in the presence of pyridine. Introduction A cyanine dye is constituted of two nitrogen centers, one of which is positively charged and is linked by a conjugated chain of an odd number of carbon atoms to the other nitrogen [1]. Cyanine dyes have particular characteristics as large molar extinction coefficient, high fluorescence efficiency, large tunable range of maximum absorption wavelength and relatively high stability [2, 3]. Has been due to these characteristics they have been used as functional dyes in optical disks as recording media, in industrial paints for trapping of solar energy, as spectral sensitizers for silver halide photography, for biomedical applications, photodynamic therapy and others [2]. Synthetic dyes can be classified as affinity ligands when they are capable to bind to proteins through the binding sites present on a protein by mimicking the substrate, co-inhibitor or other binding agents. In dyes structure generally contain aromatic rings, sometimes heterocyclic, often fused, in some cases also contain different types of functional groups and by the definition of dye, a long series of conjugated double bonds must be present to give a strong absorption of light in the visible spectrum. Dye-ligands have been considered as one alternative to natural counterparts for specific affinity chromatography. A number of textile dyes, known as reactive dyes, have been used for protein purification in dye-ligand affinity systems, since they bind a variety of proteins in a selective and reversible manner [4]. Affinity chromatography, allows the purification of proteins based on biological functions rather than on individual physical or chemical properties giving some advantages by reducing the overall working volumes and processing coasts. The global interaction between the target molecule and the immobilized ligand on the matrix is a reflection of the various molecular interactions

involved, namely, electrostatic, hydrogen bonding, hydrophobic and van der Waals interactions. Where the biological ligands suffers from several disadvantages like instability, high costs and difficulty to immobilization, the counterpart synthetic ligands offers several advantages since they are easy and readily coupled to a greater variety of matrices, are resistance to biological degradation and display the capacity to be complementary of a great variety of biological macromolecules. In the past, indocarbocyanines have been used in a large variety of applications but it has never been investigated the capacity to use this cationic dye as a ligand in dye-AC. The synthesis of indocarbocyanines with two carboxylic groups present in their structure makes these dyes potentially reactive and capable of bonding onto hydroxylic macromolecules like cellulose or agarose, by any esterification method. The molecular structure of these dyes offers multiple possibilities for interaction at many sites with the target proteins. Recently, a carboxyalkylthiacarbocyanine bounded onto cellulose beads proved to be an effective and selective tool in the separation of an artificial mixture of standard proteins [5]. Materials and Methods All the reagents were of the highest purity available, used as received and were purchased from Sigma Aldrich, except the 2,3,3-trimethylnaphto[1,2-d]pyrrole which was obtained from Acros. Solvents were of analytical grade and were dried over 3 Å molecular sieves prior to use. The derivatized 2,3,3-trimethylindolenines (1 a-c) were obtained reacting p-substituted phenylhydrazine with 3-methylbutan-2-one by conventional Fisher indole synthesis (Scheme 1) [6].

R

NH NH2

CH3CCH(CH3)2

O

N

R

1

1 a b c

R= HSO3 COOH NO2

Scheme 1: Derivatized 2,3,3-trimethylindolenine Quaternization of compounds 1a-c, commercial 2,3,3-trimethylindolenine and 2,3,3-trimethylnaphto[1,2-d]pyrrole (1 eq.) was achieved by a melting process at

90

150º C, in the presence of 11-bromoundecanoic acid (1.1 eq.) (Scheme 2). The reaction was completed after 48h and the solids were recrystallized from methanol/diethyl ether. The carboxyindocarbocyanines (3 a-e) were obtained by refluxing a solution of the quaternarium ammonium salt (2 a-e) and triethyl orthoformate (2,1 eq./1 eq. salt) in pyridine (10 mL /g salt).

2

3

(C2H5O)3CH

pyridine

N

R

R`

Br(CH2)10COOHN

(CH2)10

COOH

R

R`

Br

N

(CH2)10

COOH

R

R`

N

(CH2)10

COO

R

R`

4

N

(CH2)10

COOH

R

R`

IN

(CH2)10

COOH

R

R`

14% KI solution

2-4 a) b) c) d) e)

R= HSO3 COOH NO2 H C* R`= H H H H C*

Scheme 2: Derivatized Indocarbocyanines synthesis All the reactions were completed at least before 18 h. The dye was precipitated in oil with petroleum ether and the mother-liquors decanted. The oil was dissolved and boiled with a 5% H2SO4/acetonitrile solution. A 14% KI aqueous solution was added and heated to reflux. Acetonitrile was almost removed and the remaining solution or suspension so obtained was cooled to room temperature and then refrigerated overnight. The resulting crystalline solid was collected by filtration under reduced pressure and washed several times with diethyl ether obtaining the carboxyindocarbocyanines 4 a-e. Results and Discussion The preparation of nitro, sulphonic and carboxylic indocarbocyanine dyes envisioning their posterior use as ligands for AC, intended to clarify the influence of several structural variations in the indocarbocyanine dye non substituted base dye 4d. As examples, while the introduction of additional carboxyl groups in 4b will incremented hydrogen bond between the immobilized ligand and target proteins, the introduction of a second aromatic moiety in 4e will potential increase the – interactions.

N N

(CH2)10 (CH2)10

COOH COOH

I

4e All dyes and precursors herein described were fully spectroscopy characterized. As a typical example, the 1H NMR (250MHz, d6-DMSO) spectrum of 4e revealed ppm: 1.17-1.48 (m, 28H, CH2), 1.71-1.80 (m, 4H, CH2), 2.00 (s, 12H, CH3x4), 2.23 (t, J = 7.5 Hz, 4H, CH2COOH) 4.28 (t, J = 7.5 Hz, 4H, NCH2), 6.65 (d, J = 14.0 Hz, 2H, C ), 7.54 (t, J = 7.5 Hz, 2H, ArH), 7.69 (t, J = 8.0 Hz, 2H, ArH), 7.80 (d, J = 8.5 Hz, 2H, ArH), 8.10 (t, J = 8.5 Hz, 4H, ArH), 8.30 (d, J = 8.5 Hz, 2H, ArH), 8.58 (t, J = 14.0 Hz, 1H, C ); and the 13C NMR spectrum of 4e revealed ppm: 24.3 (CH2), 25.9 (CH2), 27.0 (CH3), 27.3 (CH2), 28.3 (CH2), 28.6 (CH2), 28.6 (CH2), 28.7(CH2), 28.7 (CH2), 33.1 (CH2), 43.9 (CH2), 50.5 (3-C), 102.0 ( CH), 111.7 (CH), 122.1 (CH), 125.0 (CH), 127.3 (C), 127.8 (CH), 129.9 (CH), 130.4 (CH), 131.4 (C), 133.0 (C), 139.5 (C), 148.4 ( CH), 173.2 (C), 175.0 (C). For example, the 1H NMR (250MHz, d6-DMSO) spectrum of 4d revealed ppm: 1.20-1.47 (m, 28H, CH2), 1.68-1.75 (m, 16H, CH2 + CH3x4), 2.14 (t, J = 7.0 Hz, 4H, CH2COOH) 4.13 (t, J = 7.0 Hz, 4H, NCH2), 6.57 (d, J = 13.5 Hz, 2H, C ), 7.29 (t, J = 7.0 Hz, 2H, ArH), 7.40 (m, 4H, ArH), 7.64 (d, J = 7.5 Hz, 2H, ArH), 8.37 (t, J = 13.5 Hz, 1H, C ). Conclusions The synthesis of some derivatized indocarbocyanine was described, starting from p-substituted phenylhydrazine. This synthetic route allows derivatized indocarbocyanines with different groups as sulphonic, carboxylic and nitro. These dyes will be tested as new ligands in Affinity Chromatography. References [1] Mishra A., Behera R. K., Behera P. K., Mishra B. K., and Behera G. B. Chem Rev 100, 1973, 2000 [2] Fu Y.-L., Huang W., Li C.-L. , Wang L.-Y., Wei Y.-S., Huang Y., Zhang X.-H., Wen Z.-Y. and Zhang Z.-X. Dyes Pigments 82, 409, 2009 [3] Chipon B., Clave G. Bouteiller C., Massonneau M., Renarda P.-Y., and Romieu A. Tetrahedron Lett 47, 8279, 2006 [4] Denizli A. and Pis¸kin E. J Biochem Bioph Meth 49, 391, 2001 [5] Boto REF, Anyanwu U., Sousa F.,Almeida P and Queiroz J.A. Biomed Chromatogr 23, 987, 2009

[6] Illy H. and Funderburk L.J Org Chem 11, 4283, 1968 Acknowledgements The authors are grateful to FCT (Lisbon), for financial support PTDC/QUI-QUI/100896/2008.

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Comparação de métodos analíticos para a determinação do teor de sulfato e nitrato na água das ribeiras Degoldra e Carpinteira

A.M.M.M.B. Amaro1, E.M. Fernandes1, M.H.B. Nunes1, M.I.A. Ferra1, M.J.R.G.R. Pires1

1Unidade de Materiais Têxteis e Papeleiros, Dep. Química, Universidade da Beira Interior, 6201-01 Covilhã Abstract Water samples were collected from Degoldra and Carpinteira streams, between November 2007 and March 2008, to determine sulphate and nitrate concentrations. Ionic chromatography and turbidimetry were used to quantify the sulphate ion and these two techniques were compared by means of the regression analysis and paired t – test methods. It was concluded that both are statistically equivalent. Nitrate concentrations were determined only by ionic chromatography, since the UV absorption spectrophotometry was not adequate for this stream water, due to the presence of organic matter, measured by chemical oxygen demand (COD). Introdução As duas ribeiras que descem da serra da Estrela, Carpinteira e Degoldra, atravessam a cidade da Covilhã e estiveram na génese do desenvolvimento da indústria de lanifícios. Os iões em estudo, sulfato e nitrato, constituem as formas termodinamicamente mais estáveis dos compostos azotados e sulfurosos, podendo ser provenientes dos processos de tingimento ligados à indústria têxtil. O presente trabalho teve como objectivos a comparação dos métodos analíticos usados na determinação dos parâmetros sulfato e nitrato nas águas das duas ribeiras da Covilhã e a avaliação da qualidade destas águas superficiais, relativamente a estes dois parâmetros.

Material e Métodos Os dois parâmetros analíticos objecto de estudo, sulfato e nitrato, foram monitorizados, entre Novembro de 2007 e Março de 2008, nas ribeiras Degoldra e Carpinteira. Seleccionaram-se estrategicamente os locais de recolha das amostras: P1, P2 e P3 na ribeira da Degoldra e P4, P5, P6 e P6’ na ribeira da Carpinteira. As designações P6 e P6’ correspondem a duas amostras recolhidas no mesmo dia, no mesmo local, mas a horas diferentes, conforme se regista na Tabela 1. As amostras foram recolhidas, transportadas e conservadas de acordo com as indicações da literatura, bem como os métodos analíticos usados [1]. Os reagentes usados na preparação das soluções foram de qualidade analítica p.a. (pró-análise) e a água usada na preparação das mesmas foi água ultra-pura cuja condutividade, k, é igual ou inferior a 0,5 μS cm-1. Foi usado um sistema cromatográfico que consiste num injector marca Waters, modelo 717 Plus e numa coluna cromatográfica IC-Pak A HC (150x4,6 mmx10 μm). Os ensaios foram realizados num espectrofotómetro de UV-Vis de feixe simples, marca Termo Electron Corporation, modelo Heλios γ . O digestor para a determinação de CQO é da marca Merck, modelo Thermoreaktor TR 300. Resultados e Discussão O teor de sulfato foi determinado por cromatografia iónica e pelo método turbidimétrico. Os resultados apresentam-se na Tabela 1.

Tabela 1 - Teores de ião sulfato, mg L-1, obtidos por cromatografia iónica(1) e pelo método turbidimétrico(2)

2007 2008 Ribeiras

Pontos de recolha 9/Nov 28/Nov 12/Dez 9/Jan 23/Jan 20/Fev 5/Mar 19/Mar

P1(1) 1,5 1,0 1,4 1,3 1,2 1,3 <1,0 <1,0 P1(2) 2,1 1,1 1,6 1,4 1,1 1,6 1,2 1,4 Degoldra P2(1) 15,5 14,5 14,9 9,8 9,0 5,9 5,7 4,6 P2(2) 15,9 15,1 14,9 9,8 7,5 4,7 5,2 4,8 P3(1) 23,4 21,3 22,8 10,2 19,0 17,7 16,1 17,2 P3(2) 24,1 20,5 22,1 9,7 19,1 17,1 16,7 16,4

P4(1) 1,5 1.2 1,6 1,5 1,7 1,1 1,2 <1,0 P4(2) 1,4 1,0 1,4 1,2 1,4 1,5 1,8 0,9 P5(1) 3,6 3,4 3,9 3,0 2,8 2,4 2,3 1,8 P5(2) 3,8 2,9 3,8 2,2 2,3 2,5 2,3 2,4

Carpinteira

P6(1) 12,3 10,1 12,4 8,7 9,3 5,8 5,1 5,6 P6(2) 15,5 9,6 12,1 8,2 9,9 5,5 4,4 4,3 P6’(1) - - 8,7 7,3 6,6 7,0 7,7 6,8 P6’(2) - - 7,3 7,2 7,4 7,6 7,4 6,0

A comparação das duas metodologias analíticas, para o parâmetro sulfato, foi feita através do método da regressão linear e do teste t - emparelhado. A Figura 1

mostra o gráfico da regressão linear. No eixo das abcissas está indicado o teor de sulfato/ mg L-1, obtido por

92

cromatografia iónica, e no eixo das ordenadas o obtido pelo método turbidimétrico [2]. A equação da recta é

c(T) = 1,0097c(CI) – 0,4250 (1)

com coeficiente de correlação 0,9968 e desvio padrão 0,63.

Figura 1. Turbidimetria (T) vs cromatografia iónica (CI)

Foram determinados os intervalos de confiança para a ordenada na origem e para o declive, para o nível de

confiança de 95%: -0,06 < ordenada na origem < 0,91 e 0,97 < declive < 1,05. Pela análise destes intervalos, verifica-se que a ordenada na origem engloba o zero e o declive engloba o um. Assim, pode-se concluir que os dois métodos conduzem a resultados idênticos [2]. Para aplicação do teste t – emparelhado, calculou-se o valor médio e o desvio padrão das diferenças dos pares de valores obtidos pelos dois métodos (Tabela 1). Através da expressão 2 [2]

nS

xt

d

dcalculado =

(2)

verifica-se que tcalculado = 2,79 > ttabelado = 2,05, o que significa que, para um nível de confiança de 95%, os dois métodos conduzem a resultados ligeiramente diferentes. No entanto, atendendo a que a dimensão da amostra é pequena e que os valores de tcalculado e ttabelado são próximos, pode-se concluir que os resultados obtidos pelos dois métodos são idênticos, tal como observado por aplicação da regressão linear. O teor em ião nitrato, correspondente a cada uma das ribeiras, obtido por cromatografia iónica, está indicado na Tabela 2.

Tabela 2 - Teor de ião nitrato, mg L-1, obtido por cromatografia iónica

2007 2008 Pontos

de recolha 9/Nov 28/Nov 12/Dez 9/Jan 23/Jan 20/Fev 5/Mar 19/Mar P1 1,5 1,0 1,4 1,3 1,2 1,3 <1,0 <1,0 P2 15,5 14,5 14,9 9,8 9,0 5,9 5,7 4,6 P3 23,4 21,3 22,8 10,2 19,0 17,7 16,1 17,2 P4 1,5 1.2 1,6 1,5 1,7 1,1 1,2 <1,0 P5 3,6 3,4 3,9 3,0 2,8 2,4 2,3 1,8 P6 12,3 10,1 12,4 8,7 9,3 5,8 5,1 5,6 P6’ - - 8,7 7,3 6,6 7,0 7,7 6,8

A presença de matéria orgânica nas amostras, confirmada através de medições da carência química de oxigénio (CQO), impossibilitou a determinação do teor em nitrato por espectrofotometria de absorção na região do ultravioleta [1]. Conclusões Os métodos usados na quantificação do ião sulfato na água das duas ribeiras conduziram a resultados idênticos. Assim, esta análise pode ser realizada através do método turbidimétrico, sem recorrer a equipamento mais dispendioso. Verificou-se que, devido à matéria orgânica presente na água, a espectrofotometria de absorção molecular não é adequada para a quantificação do ião nitrato, sendo então necessário recorrer a outro método de análise, como a cromatografia iónica. De um modo geral, a ribeira Degoldra apresenta valores mais elevados do que a Carpinteira, quer para o ião sulfato quer para o ião nitrato. No entanto, os resultados indicam concentrações muito inferiores aos valores

paramétricos, referidos na legislação, 250 mg L-1 e 50 mg L-1 para os iões sulfato e nitrato, respectivamente [3]. Referências 1. APHA, AWWA, WPCF, Standard Methods for the

Examination of Water and Wastewater, 21st Edition, 2005

2. Miller, J.C., Miller, J.N., Statistics for Analytical Chemistry, Third Edition, Ellis Horwood, 1993

3. Decreto – Lei nº 306/2007, de 27 de Agosto Agradecimentos Os autores agradecem o apoio financeiro da Unidade de Investigação de Materiais Têxteis e Papeleiros, Fundação para a Ciência e Tecnologia (FCT).

93

GC-MS Analysis of Essential Oil of Rosmarinus officinalis L. from PNTI. João Paulo Araújo1, Arlindo Gomes1, Jesus Rodilla1, Paula Gonçalves2, Lúcia Silva1.

1 Unidade de Materiais Têxteis e Papeleiros, Universidade da Beira Interior, Rua Marquês d’Ávila e Bolama, 6200 Covilhã, [email protected]

2 Parque Natural do Tejo Internacional e Reserva Natural da Serra da Malcata Abstract The chemical composition of the essential oils extracted from Rosmarinus officinalis L., collected in three different places from Parque Natural do Tejo International (PNTI), was obtained by hydrodistillation followed by gas chromatography – mass spectrometry (GC-MS). The mains components were camphor (19.19-20.50%); β-myrcene (12.43-15.93%); 1,8-cineol (11.65-15.35%). Introduction Rosemary (Rosmarinus officinalis L.) is an aromatic evergreen shrubby herb highly distributed in Portugal. It is a well-known and greatly valued medicinal and cosmetic, that is widely used in pharmaceutical products and folk medicine as a digestive, tonic, astringent, diuretic, diaphoretic and useful for urinary ailments. It is also use as condiment in food and as aromatic and ornamental plant in gardens. Materials and Methods Plant material The aerial parts of Rosmarinus officinalis L were collected, during the vegetative phase (May 2007), in Parque Natural do Tejo Internacional (Portugal), in three different places: near Castelo Branco (sample R1) Malpica do Tejo (sample R2) and Rosmaninhal (sample R3). The collective sample was constituted of a mixture of 10–12 individual plants. The oils were stored in dark glass bottles in a freezer,

until they were used. The oil yield was approximately 2,4 %; 3,2% e 3,0% for samples R1; R2 e R3 respectively. Isolation procedure The essential oils of each collective sample were isolated from fresh plant material (50 g) by hydrodistillation, for 2 h, using a Clevenger-type apparatus. Gas chromatography Gas chromatography analyses were performed using a GC/MS unit consisted of a Fisons 8000 gas chromatograph coupled to a Fisons 800 VG TRIO 1000. The analysis was carried out using a DB-5MS fused-silica column (30 m×0.25 mm, film thickness 0.25 μm, J & W Scientific Inc., Rancho Cordova, CA, USA). The operating conditions were as follows: injector temperature, 250 °C; carrier gas, Helium 1.6 mL/min. Oven temperature programme was 40°C–250°C at the rate of 4 °C/ min. Mass spectrometer conditions were: ionization potential 70 eV; electron multiplier energy 2000 V. The samples were injected using a split sampling technique, ratio 1:50. The percentage composition of the oils was computed by the normalisation method from the GC peak areas, calculated as mean values of two injections from each oil, without using correction factors. The identities of the oil components were established from their GC retention indices, relative to C7–C25 n-alkanes, by comparison by computer matching with the Wiley mass spectra library, whenever possible, by co-injection with standards available in the laboratory.

Results and Discussion Chemical analysis of the essential oils of Rosmarinus officinalis L. led to identification of 48 components (Table 1). The major components of Rosmarinus officinalis L. oil were camphor (19.19-20.50%); β-myrcene (12.43-15.93%); 1,8-cineol (11.65-15.35%). The composition of essential oils of Rosmarinus officinalis L. collected in three different place are very similar.

Sometimes change the percentage of some constituents. Acknowledgements

This study was supported by AGRO 800 project “Rede Nacional para a conservação e utilização das plantas aromáticas e medicinais”.

94

Table 1 .Oil yields and percentage composition of the oils isolated from R.. officinalis L. collected during the vegetative phase

Compounds Tr (min) R1 % R2 % R3 %

1 Tricyclene 8.270 0.26 0.27 0.24

2 à-Thujene 8.533 0.69 0.56 0.35

3 α-Pinene 9.043 4.80 5.18 4.98

4 Camphene 9.868 3.21 3.54 2.86

5 Trans-verbenol 9.980 0.22 0.24 0.21

6 β-Pinene 11.422 3.04 3.65 2.57

7 β-Myrcene 13.022 15.15 15.93 12.43

8 α-Phellandrene 13.425 0.48 2.25 1.02

9 α-Terpinene 14.059 1.04 1.03 1.12

10 1,8-Cineole 15.402 11.65 15.35 12.66

11 β-cis-Ocimene 15.642 1.17 2.82 3.12

12 β-trans-Ocimene 16.141 0.16 0.26 0.31

13 γ-Terpinene 16.910 2.52 1.54 2.42

14 cis-β-Terpineol 17.709 0.35 0.27 0.30

15 Terpinolene 18.622 1.08 0.84 1.73

16 Fenchone 18.754 1.82 1.52 1.02

17 Linalol 20.866 0.49 0.66 0.90

18 Camphor 23.759 19.58 20.50 19.19

19 1H-Inden-1-one, 2,3,3a,4,5,7a-hexahydro-5-methyl- 24.340 0.56 0.21 0.62

20 trans-3(10)-Caren-2-ol 24.677 0.11 0.10 0.11

21 Isoborneol 25.098 2.88 3.16 2.37

22 4-Terpineol 25.652 1.78 1.87 2.07

23 α-Terpineol 27.039 3.66 4.41 4.14

24 Verbenone 27.663 2.06 1.16 1.14

25 Pulegone 29.448 0.22 0.12 0.16

26 cis-Myrtanol 30.090 0.20 0.14 0.31

27 Piperitone 30.600 0.15 0.31 1.89

28 Bornyl acetate 32.624 1.55 1.53 0.12

29 à-Ylangene 37.961 0.14 0.07 0.37

30 α−Copaene 38.441 0.37 0.17 0.46

31 cis-Jasmone 40.133 0.41 0.13 0.39

32 Eugenol methyl ether 40.876 0.16 0.39 0.04

33 Caryophyllene 41.457 3.99 1.74 3.78

34 á-Cubebene 41.949 0.12 0.06 0.07

35 1,1,7-Trimethyl-4-methylenedecahydro-1H-cyclopropa[e]azulene 42.427 0.10 0.03 0.95

36 Humulene 43.642 1.31 0.42 1.02

37 α-Cadinene 44.742 0.11 0.25 0.15

38 ç-Muurolene 45.023 0.56 0.43 0.60

39 à-Cubebene 46.060 0.26 0.21 0.27

40 à-Muurolene 46.532 0.27 0.15 0.29

41 á-Cadinene 46.738 0.59 0.24 0.52

42 γ-Cadinene 47.847 0.86 0.31 0.67

43 á-Sesquiphellandrene 48.239 0.13 0.12 0.10

44 Cadina-1,4-diene 48.584 0.10 0.09 0.13

45 2-(4a,8-Dimethyl-2,3,4,4a,5,6-hexahydronaphthalen-2-yl)propan-1-ol 52.191 0.13 0.23 0.15

46 τ-Cadinol 55.307 0.20 0.16 0.11

47 Caryophyllene oxide 56.190 0.82 1.01 0.66

48 à-Bisabolol 58.041 0.55 0.35 0.24

Total of compounds identified 92.06 96.07 91.35

95

Derivatized Carboxythiacarbocyanines as New Ligands in Affinity

Chromatography R. E. F. Boto1, M. Madej1, P. Almeida1

1Health Sciences Research Center, University of Beira Interior, 6201-001 Covilhã, Portugal Abstract Following our previous work on the preparation of thiacarbocyanines derived from benzothiazole we herein present the synthesis of two new affinity chromatographic ligands. Thiacarbocyanines has been derivatized introducing a benzamide and an acetamide group in the 6 position of the benzothiazole terminal moiety of the cyanine dye. The dicarboxydecyl chain introduced in both thiacarbocyanines makes these dyes reactive and therefore able to bind onto hydroxylic macromolecules like cellulose by an esterification method, using a cure method previously developed in our research group1.

Introduction Affinity chromatography (AC) is unique among separation methods. It enables the purification of almost any biomolecule based on biological functions rather than on individual physical or chemical properties and it is considered the most powerful tool for the purification of biological active molecules. Since the introduction of this technique in 1968, thousands of different molecules such as enzymes, antibodies, hormones, vitamins, receptors, a large variety of proteins and glycoproteins, RNA, DNA and even bacteria have been separated and/or purified by affinity chromatography. The immobilized ligand is the key factor that determines the success of any affinity chromatographic method, since it will promote the specific interaction with the target biomolecule. A wide range of functional materials have been used as ligands such as dyes, enzymes, coenzymes, antibodies, amino acids, oligopeptides, proteins, metal chelates, oligonucleotides, etc., being extremely specific in most cases. Complementary ligands have also been used to recognize the biopolymers to be separated with enhanced specificity to be purified, e.g. enzymes and their substrates, hormones and their receptors, antibodies and their antigens. The development of synthetic ligands is intended to combine the selectivity of natural ligands with the high capacity, durability and cost-effectiveness of these ligands. Dye-AC is widely used due to the low cost of dyes, their commercial availability, resistance to biological and chemical degradation and easy immobilization, especially on matrices bearing hydroxyl groups. Cyanines have found multiple and extensive applications as functional dyes in many different fields, but their use as biomimetic ligands for AC remains to be explored. Recently, a cyanine chromatographic support prepared by linking a dicarboxydecylthiacarbocyanine hydrogen sulfate dye onto cellulose beads, proved to be an effective and selective tool in the separation of BSA, -chymotrypsin and lysozyme from an artificial mixture2. A

dissociation constand (Kd), in the range of 10-5 M was further determined for lysozyme showing a real affinity interaction between lysozyme and the immobilized cyanine. In order to better understand the influence in the chromatographic behavior of further structural variations in this ligand, namely by the introduction of an additional amide groups as typical hydrogen bond responsible, new benzamide and acetamide dicarboxydecylthiacarbo cyanine dyes were prepared and herein summary described.

Materials and Methods Solvents were of analytical grade and were dried over 3 Å molecular sieves prior to use. The synthesis of the quaternary salts 5 is described in scheme 1 and involves four sequential reactions. The starting material, 2-methylbenzothiazole (1) was obtained from Sigma Aldrich in analytical grade and used as received. The 2-methyl-6-nitrobenzothiazole (2) was prepared by direct nitration, by stirring 1 with concentrated acid sulfuric (6 eq) in an ice bath and add dropwise a solution of nitric acid/sulfuric acid (3 eq/1 eq). The reaction was completed after 30 min and the solution was added to a mixture of ice and distillated water. The solid formed was filtrated and recrystallized from methanol.

S

N

S

N

O2N

S

N

H2NS

N

NC

H

O

R

HNO3 / H2SO4

Fe / HClUltrasound

Br(CH2)10COOH

150º C

0º C

0º C

1 2

34

5 a)

5 b)

S

N

NC

H

O

R

(CH2)10

COOH

Br

4a - R = CH3

4b - R = C6H5

a) acetic anhydrideb) benzoyl chloride

Scheme 1- Quaternary salts synthesis

The 6-amine-2-methylbenzothiazole (3) was obtained by reduction of 2 under sonochemical conditions, over 1h, with Fe (4 eq) and concentrated HCl (1.8 eq), in an 80% ethanol/water solution3. Iron oxide precipitated was removed by filtration and washed with ethanol. The solvent was evaporated to dryness under reduce pressure and the resulting solid residue was extracted into a heterogeneous mixture of dichloromethane and 10% aqueous solution of Na2CO3. Dichloromethane extracted

96

was dried over anhydrous Na2SO4 and removed under vacuum. The solid obtained was recrystallized from methanol/ diethylic ether. The reaction of 3 with acetic anhydride (1.15 eq) in chloroform in an ice bath gives the N-(2-methylbenzo[d]thiazol-6-yl)acetamide (4a) after 1h. The chloroform was removed under vacuum and the solid was washed several times with diethyl ether. The reaction of 3 with benzoyl chloride (1.15 eq) in chloroform and pyridine (1.1 eq), in an ice bath, gives the N-(2-methylbenzo[d]thiazol-6-yl)benzamide (4b) after 1h. The solution was washed with 1% HCl solution to remove pyridine. The organic phase was washed with 5% aqueous solution of Na2CO3 and dried under anhydrous Na2SO4. The remaining chloroform solution was removed under reduced pressure and the resulting solid was washed several times with diethyl ether. Quaternization of compounds 4a and 4b was achieved by a melting process at 150º C, in the presence of 11-bromoundecanoic acid, to afford 6-acetamido-3-(10-carboxydecyl)-2-methyl benzo[d] thiazol-3-ium salt (5a) and 6-benzamido-3-(10-carboxydecyl)-2-methylbenzo[d] thiazol-3-ium salt (5b), respectively. The obtained solids were washed several times with diethyl ether and recrystallized from methanol/diethyl ether. The final derivatized thiacarbocyanines 6a and 6b were prepared by the condensations of appropriate quaternary salts 5a and 5b with triethylorthoformate (2.05 eq), in refluxing pyridine (10 mL/g quaternary salt) for 18 h (Scheme 2).

S

N

NC

H

O

R

(CH2)10

COOH

2

Br

S

N

NC

H

O

R

(CH2)10

COOH

N

S

(CH2)10

COOH

N C

H

O

R

Br

triethylorthoformate

pyridine, 120º C

5a - R = CH3

5b - R = C6H5

6 a)

6 b)

5% H2SO4 in CH3CN

7 a)

7 b)

S

N

NC

H

O

R

(CH2)10

COOH

N

S

(CH2)10

COOH

N C

H

O

R

HSO4

Scheme 2- Derivatized thiacarbocyanine synthesis.

After cooling to room temperature, diethyl ether was added and the resulting mixture cooled in the refrigerator to allow complete precipitation. The crystalline product obtained was collected by filtration under reduced pressure and washed with diethyl ether. The dyes were readily undergoing counter-ion exchange to hydrogen sulfate by the adding a 5% H2SO4 solution to an acetonitrile dye solution. The resulting solution or

suspension so obtained was heated until reflux and then allow cooling to room temperature and refrigerated overnight. The resulting crystalline product was collected by filtration under reduced pressure, washed with diethyl ether and recrystallized from dry acetonitrile. Dyes 7a and 7b were fully characterized by 1H and 13C NMR. A thermogravimetric analysis has also been done to prove the required stability of these dyes at the range of temperatures used in the curing process. Dyes 7a and 7b has been post-grafted onto beaded cellulose by a curing method (REF) using the same conditions and methodology. Chromatographic studies are actually being conducted.

Results and Discussion The introduction of the acetamide and benzamide groups in the thiacarbocyanine structure was achieved in order to explore the introduction of an additional amide group in relation to the hydrophobic, ionic and – interactions already present in the cyanine base dye. These ligands, after suitable immobilization onto cellulose, are expected to show the influence of a further hydrogen bond group in their chromatography behavior. As representative example of the new cyanine dyes characterization, the 1H NMR (250.13 MHz, DMSO-d6) spectrum of 4a revealed: 2.06 (s, 3H, NHCOCH3); 2.73 (s, 3H, 2-CH3); 7.46 (dd, J = 9.0 and 2.0 Hz, 1H, 5-CH); 7.80 (d, J = 9.0 Hz, 1H, 4-CH); 8.38 (d, J = 2.0 Hz, 1H, 7-CH); 10.1 (s, 1H, NHCOCH3); and the 1H NMR (250.13 MHz, DMSO-d6) spectrum of 4b revealed: 2.78 (s, 3H, 2-CH3); 7.52-7.64 (m, 3H, aromatic H); 7.75 (dd, J = 9.0 and 2.0 Hz, 1H, 4-CH); 7.88 (d, J = 9.0 Hz, 1H, 5-CH); 7.98 (d, J = 8.0 Hz, 2H, aromatic H); 8.57 (d, J = 2.0 Hz, 1H, 7-CH); 10.47 (s, 1H, NHCO). Furthermore, thermogravimetric results obtained for both thiocarbocyanines points to a minor degradation at the temperature of 250º C. However, at the 220º C operating temperature used in the immobilization cure conditions, no significant weight loss was observed. Following these results, both dyes were already post-grafted onto beaded cellulose by the curing method already described and some preliminary AC studies were done showing different chromatography behaviour in relation to the known cyanine base dye AC ligand.

Conclusions The synthesis of two new amides thiacarbocyanines were herein presented. Preliminary AC results stress the role of the introduction of amide groups in the behaviour of these dyes as ligands in AC.

References 1. Silva A., Boto R.E.F., El-Shishtawy R.M. and Almeida

P., Eur Polym J; 42, 2270, 2006. 2. Boto R.E.F., Almeida P. and Queiroz J.A., Biomedic

Chromatogr, 22, 278, 2008. 3. Hrobárik P., Sigmundová I. and Zahradnik P.,

Synthesis, 4, 600, 2005.

Acknowledgements The authors are grateful to FCT (Lisbon), for financial support PTDC/QUI-QUI/100896/2008.

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1

Biodegradability Study of Cork Boiling Wastewater

N. Canto1, A.C. Gomes1, R.M.S. Simões1, L. Silva1, A. Albuquerque2

1Department of Chemistry & UMTP, University of Beira Interior, 6201-001 Covilhã, Portugal

2Department of Civil Engineering, University of Beira Interior, 6201-001 Covilhã, Portugal Abstract The biodegradability of cork boiling wastewater was studied after application of ozone in gas phase. This ozone pretreatment was performed at three different pH, natural pH (pH=6.60), initial alkaline pH (pH=10) and initial acid pH (pH=5). The ozone applied to the effluent had different extensions and samples were taken at 10, 20, 40, 60 and 80 minutes into the assay. Biodegradability assays were performed with cork boiling wastewater before ozonation and after 10 and 80 minutes into the assay of ozonation. A steady reduction in both chemical oxygen demand (COD) and total organic carbon (TOC) were observed under the action of ozone. Biodegradability increased significantly after the effluent was subjected to the application of ozone. Introduction The largest production and manufacture of cork (outer bark of Quercus suber L.) in the world is concentrated in Mediterranean countries, like Portugal and Spain. This raw material is used for numerous applications, one of the most important being the manufacture of cork wine stoppers [1]. Cork boiling has two purposes: to improve the mechanical properties of the cork bark (elasticity, texture, consistency, etc.) and to remove undesired water-soluble substances [2]. In the cork industrial process, the first step is focused on the cleaning, disinfecting and moistening of the raw material. For this purpose, the corkwood is immersed in boiling water (100ºC) during approximately one hour after being dried in open air from three to six months [1,3], and then, a dark wastewater is generated which contains some corkwood extracts such as phenolic acids (gallic, protocatechuic, vanillic, syringic, ferulic and ellagic), tannic fraction, 2,4,6- trichloroanisol and pentachlorophenol [1]. The presence of these organic compounds confers an important pollutant character to this processing wastewater that must be frequently renovated after a few contacts with new loads of cork (depending on the discretion of each company, some go from 6 to 8 loads while others go from 20 to 30 loads) [1,3]. Then, the effluent must be treated before its discharge into public courses, in order to achieve the increasing stringent legislation on discharges imposed by the environmental authorities [1]. Cork boiling wastewater can be characterized by high chemical oxygen demand (COD), biochemical oxygen demand for five days of incubation (BOD5) and polyphenols content, in the range of 4.5–5.5 g/L, 1.1–1.8 g/L and 0.6–0.9 g/L, respectively, and by an acid pH around 5 [3]. Despite the fact that such parameters exceed those legally admitted in

residual wastewaters to be released to the environment and that toxicological properties have been described for these effluents, cork boiling wastewaters are frequently discharged without any previous treatment. In fact, cork boiling wastewater treatment imposes some technical and economic constraints, mainly related with the high volumes produced (400 L/ton cork) and the complex nature of the effluent, which requires sophisticated treatment processes [3]. In spite of biodegradation is viewed as a sustainable process of wastewater treatment, the complicated nature of this wastewater (BOD5/COD=0.19) makes biological treatment ineffective [4]. This treatment presents several problems in cork boiling wastewaters due to the toxicity of these effluents that lead to a partial inhibition of the biodegradation, because some microorganisms are particularly sensitive to the organics present, especially the polyphenolic compounds [5]. Several purification techniques can be applied for the reduction of the organic pollutant load present in this effluent, in order to obtain water with the quality required for its discharge. Thus, chemical procedures by using oxidants like ozone, UV radiation and Fenton’s reagent has been previously tested with success in the purification of the cork processing wastewater [1]. One widely used procedure is ozonation (ozone, O3). This has the advantage of forming low molecular weight substances which are more readily biodegradable. On the other hand, biological treatments have also proved themselves to be an efficient method, yielding high levels of organic matter removals. Indeed, the most promising purification technology seems to be the combination of chemical and biological treatments, such as the combination of ozonation and aerobic degradation processes, which in some cases, leads to an almost total degradation of the contaminants [6]. With the development of large-scale ozone generators along with reduced installation and operating costs, there has been increasing interest in using ozone to treat wastewater effluents containing hazardous organic and inorganic compounds. Its powerful oxidizing capabilities and the absence of hazardous decomposition products make ozone a potentially useful pretreatment agent for converting refractory compounds into substances which are treatable by one or more of the conventional methods of chemical breakdown. In some cases, ozone treatment alone may be sufficient to meet pollution standards [7]. Besides the increasing interest on ozone oxidation in water and wastewater processing, the amount of information required for better knowledge of both the products and the rate of reaction of pollutants to

98

2

be degraded by ozone on the aqueous phase is scarce. Several methodologies have been used to study the oxidation of inorganic and organic compounds by ozone. One of the most widespread methodologies utilizes a heterogeneous system where mass transfer from the gas phase to the liquid phase is concomitant with the chemical reaction [8]. This study was focused on increasing the biodegradability of cork boiling wastewater after it being subjected to a pretreatment with ozone in gas phase in a laboratory scale. The pretreatment with ozone was performed with three different pH; natural pH, alkaline pH and acid pH. The biodegradability was studied using the BOD OxiTop method. Materials and Methods Cork boiling wastewater In this study, ozone and biodegradability assays were performed with one sample of cork boiling wastewater (E11). The results of the effluent characterization are presented in Table 1 for COD, BOD5, TOC (Total Organic Carbon), SS (Solid Suspense) and pH determinations. Table 1: Characteristics of cork boiling wastewaters collected from the cork industry (determinations performed accordingly Standard Methods).

Parameters (units) Effluent 11 (E11)

pH (-) 6.63 COD (mg O2/L) 1317 BOD5 (mg O2/L) 418

BOD5/COD 0.32 TOC (mg C/L) 615

SS (mg/L) 500 Ozone experimental setup A Fischer Model 502 (Bonn, Germany) ozone generator was employed to produce ozone gas from dry, pure oxygen. The ozone concentration in the gas phase is close to 50 mg/L. The ozonation was carried out by bubbling the gas phase into the cork boiling wastewater at room temperature. The reactor is a closed vessel provided with a mechanical stirrer. Ozone assays The ozone assays were performed with the effluent cork boiling wastewater. With the wastewater, the initial pH was changed. Assays were performed with initial alkaline pH (pH=10), natural pH (pH=6.60) and initial acid pH (pH=5) with the wastewater. Samples were taken at 10, 20, 40, 60 and 80 minutes into the assay. Biodegradability experimental setup The biodegradability assays were performed in an OxiTop® OC100 system (WTW). The measurement was carried out according to Standard Methods [9]. These

assays were performed in glass bottles with 250 mL of capacity, a head pressure sensor and a controller. Working volume was 200 mL, consisting of a defined mixture of aerobic biomass inoculums, phosphate buffer solution, nitrogen solution, micro and macro nutrients and cork boiling wastewater. Blanks (i.e. bottles without cork boiling wastewater) and references (i.e. acid glutamic-glucose solution) were run in parallel. Each bottle was prepared in duplicate and incubation was performed in a temperature-controlled chamber maintained at 20±0.5 ºC during 5 days. Biodegradability assays The biodegradability assays were performed with one sample of wastewater before and after the pretreatment with ozone. Biodegradability assays were only performed with the effluent before pretreatment with ozone and with samples at 10 and 80 minutes with ozone. Results and Discussion Figure 1 illustrates the ozone consumption in the reaction medium with time, for different pH. We assumed that all the ozone retained in the vessel was consumed. To calculate ozone retained, ozone concentration at inlet and outlet of the vessel were monitored. The pH of the reaction medium decreases continuously with time, as a consequence of the production of acid groups in the organic compounds. Therefore, the pH in Figure 1 is indicative, representing an average value. The results in Figure 1 suggest that at acid pH the ozone consumption rate is slightly lower than for the other reaction conditions. This is probably due to both the lower ozone decomposition rate at acid pH and lower reaction rate of molecular ozone with the effluent compounds.

Fig. 1: Ozone consumption as a function of time.

The evolution of COD as a function of ozone consumed (in relation to initial COD) is shown in Figure 2. A very positive impact on COD was observed. The same occurs for TOC (Figure 3). In order to evaluate the ozone consumption efficiency, the ratio between COD decreasing and ozone consumption was represented as a function ozone consumption. Figure 4 represents the accumulated values and shows that ozone efficiency decreases with ozone consumption. This is a natural

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3

consequence of the increasing role of less efficient secondary reactions of molecular ozone with previously oxidized compound, secondary reactions and ozone decomposition. Regarding the effect of pH in ozonation, acid pH seems to be more efficient than natural pH. These results are expected because molecular ozone is much more specific than the hydroxyl radicals, generated as a consequence of ozone decomposition at alkaline pH and as secondary reactions with chemical compounds.

Fig. 2: COD as a function of ozone consumption.

Fig. 3: TOC as a function of ozone consumption.

Fig. 4: Ozone efficiency as a function of ozone consumption.

The effect of preliminary oxidation of the effluent by ozone on the biodegradability can be observed in Figures 5 and 6. The BOD5 can duplicate with an ozone consumption close to 20% of the initial COD of the effluent. The increase in biodegradability, measured by the BOD5/COD ratio, is higher than 50%, for low ozone

consumption. For higher ozone consumptions, the biodegradability continues to increase mainly due to COD decrease. These data required further investigation, in order to minimize the ozone charge and maximize the effluent biodegradability.

Fig. 5: BOD5 as a function of ozone consumption.

Fig. 6: BOD5/COD ratio as a function of ozone consumption.

Conclusions The pre-treatment of the cork boiling wastewater with ozone improves significantly the biodegradability of the effluent. In addition it has a direct positive impact on the environmental parameters of the effluent. The ozone charge will be optimized in order to minimize the operating costs. Acknowledgements Thanks are due to FCT and FEDER for funding the Project (PTDC/AGR-AAM/102042/2008) and Nicole Canto also thanks FCT and FEDER for their Masters grants. References [1] F. J. Benítez, J. L. Acero, A. I. Leal, “Application of microfiltration and ultrafiltration processes to cork processing wastewaters and assessment of the membrane fouling”, Separation and Purification Technology 50, 354–364(2006); [2] B. Y. Lan, R. Nigmatullin, G. L. Puma, “Ozonation kinetics of cork-processing water in a bubble column reactor”, Water Research 42, 2473 – 2482 (2008);

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[3] M. D. Machado, L. M. Madeira, B. Nogales, O. C. Nunes, C. M. Manaia, “Treatment of cork boiling wastewater using chemical oxidation and biodegradation”, Chemosphere 64, 455–461 (2006); [4] T. González, J. R. Domínguez, J. Beltrán-Heredia, H. M. García, F. Sanchez-Lavado, “Aluminium sulfate as coagulant for highly polluted cork processing wastewater: Evaluation of settleability parameters and design of a clarifier-thickener unit”, Journal of Hazardous Materials 148, 6–14 (2007); [5] V. J. P. Vilara, M. I. Maldonado, I. Oller, S. Malato, R. A. R. Boaventura, “Solar treatment of cork boiling and bleaching wastewaters in a pilot plant”, Water Research 43, 4050 – 4062 (2009); [6] F. J. Benitez, J. L. Acero, J. Garcia, A. I. Leal, “Purification of cork processing wastewaters by ozone, by activated sludge, and by their two sequential applications”, Water Research 37, 4081–4090 (2003); [7] R. A. Davis, R. G. Rinker, O. C. Sandall, “Kinetics of the reaction of ozone with 2,4,6-trichlorophenol”, Journal of Hazardous Materials 41, 65-72 (1995); [8] A. C. Gomes, J. C. Nunes, R. M. S. Simões, “Determination of fast ozone oxidation rate for textile dyes by using a continuous quench-flow system”, Journal of Hazardous Materials 178, 57–65 (2010); [9] American Public Health Association, American Water Works Association, Federation WE, “Standard methods for the examination of water and wastewater”, 21th edn. ashington DC (APHA, W2005.

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Cold plasma treatment as a tool to improve recycling Filipe Gordino1, Carla Gaiolas1, Mário Nunes1, Maria Emília Amaral1,Naceur Belgacem2 e Ana Paula Costa1*

1 Research Unit of Textile and Paper Materials, Universidade da Beira Interior, 2 École internationale du papier de la communication imprimée et des biomateriaux, Institute National Polytecnique de Grenoble

Abstract The aim of this study is to modify the surface of a commercial paper, using the cold plasma treatment in order to increase its hydrophilicity, minimizing the disintegration time (less energy consumption) needed to obtain a homogeneous suspension. The plasma treatment was done using the experimental conditions of constant pressure and applied power, respectively, 700 mTorr and 200 W, resulting from optimization studies already published. Samples of reference paper (untreated paper) were characterized using contact angle test, and the samples treated with different application times of plasma (5, 10, 15, 30, 60, 120, 180 and 300 seconds ), obtaining for the time of 60 seconds a decrease in contact angle of about 70%. For times greater than this value, the contact angle remains unchanged, so it considers the value of 60 seconds as a time reference. The reference samples and those treated were disintegrates in a laboratory disintegrator (ISO 5263-1) varying the number of revolutions, that is to say 2500, 5000, 7500, 10000 and 20000 rpm. With this suspension, laboratory sheets were produced with 60g.m-2 in a conventional sheet forming, in accordance with ISO 5269-1. To quantify the effect of disintegration was measured entropy of the gray levels of images obtained by optical transmission and visualized to more or less homogeneous distribution of fibrous flocs produced. The results show that for similar entropy values (5,38 and 5,44 for the reference sample and treated sample, respectively) represented by homogeneity in the distribution fiber, it is necessary a greater disintegration time for the reference samples than for samples treated with plasma. Introduction Plasma treatment has become an important process for surface modification, since it does not use toxic substances and it is both efficient and quick. Plasma can be defined as a partially ionized gas, which generates energetic species present in the discharge, such as electrons, ions, free radicals and photons, which possess energies sufficiently high to modify the chemical bonds in the superficial layers of materials constituted of natural fibers, such as paper. Plasma discharge is a solvent-free polymerization process that has received considerable attention in the recent years, in the realm of the surface modification of various materials, such as wood [1-3] and cellulose fibers from different origins [4-7].Paper is made from lignocellulosic fibers using filtration, pressing and drying processes. The first unitary operation in the process of paper production is disintegration, with the purpose of placing the fibers in suspension, with

minimum energy consumption. This operation is important for producing paper either from the virgin fibers or recycled one’s. This study aims to modify the surface of commercial papers using cold plasma treatment; with the objective of increasing its hydrophilicity while minimizing the disintegration time (less energy consumption) required to obtain a homogeneous suspension, quantified by measuring the index of the first order entropy. Materials and Methods Raw materials This study used a commercial paper of 80 g.m-2 (reference paper), which was disintegrated in accordance with standard ISO 5263-1, laboratory sheets were produced with 60 g.m-2 in accordance with standard ISO 5269-1.

Plasma treatment The samples were treated in a plasma generator of radio frequency AEROPLASMA, equipped with a microcontroller, a vacuum system and a microwave generator to 2,54 GHz.

Figure 1. Plasma equipment.

The plasma treatment was done using the experimental conditions of constant pressure and applied power, respectively, 700 mTorr and 200 W, resulting from optimization studies already published [8-9]. Samples of reference paper (untreated paper) were subject to different times of plasma, i.e, 5, 10, 15, 30, 60, 120, 180 and 300 seconds, in the presence of air.

Samples disintegration The reference samples and those treated were disintegrates in a laboratory disintegrator (ISO 5263-1) varying the number of revolutions, that is to say 2500, 5000, 7500, 10000 and 20000 rpm. Samples Characterization The characterization of the treated and untreated samples was carried out by contact angle measurement using the equipment Dataphysics OCA Absortion Tester.

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The non-homogeneity of the distribution of fibers in the handsheets was evaluated using a laboratory technique based on image processing paper by transmission, through the index of the first order entropy, calculated from the matrix of gray level image [10]. Results and Discussion The first approach of this study was to optimize the time of plasma treatment determined by measuring the contact angle, showed in figure 2.

Figure 2. Contact angle variation with plasma treatment time. Operating conditions: power 200 W and 700 mTorr pressure.

Behaviors of the different samples in view of disintegration was carried out using image analysis equipment that allows viewing variations in mass density per square meter and evaluate the index of the first order entropy. Thus, it was found that the samples treated for the set plasma conditions, showed a reduction in the amount of flocs presented in the handsheets, compared to untreated controls, as can be seen in Fig. 3.

Figure 3. Images obtained for the handsheets in the image analysis equipment, for different revolutions. Reference paper (R) and paper treated with plasma (PT)

The non-homogeneity of the fiber distribution shown in the images from the previous figure was quantified by measuring the entropy index of gray levels, presenting the results in Fig. 4, for all the papers produced. Analyzing the samples for the same index of the first order entropy, for instance, the value 5,6, the samples treated with plasma show a halving in the number of revolutions need for disintegration (from 10 000 to 5 000 rpm).

Figure 4. Index of the first order entropy variation with the applied revolutions in disintegration, for paper reference and papers treated with plasma. Conclusions The present results demonstrate that the plasma treatment can contribute positively for the paper industry. The surface changes of the samples treated with plasma promote ease of disintegration, reducing energy consumption and thus a capital gain. This study is a preliminary work of this group aimed at applying this technique in future recycling process, using different operating conditions in order to facilitate References [1] Westerlind, B., Larsson, A., and Rigdahl, M., International Journal of Adhesion and Adhesives, 7, 141, 1987; [2] Verreault, M., Klemberg-Sapieha, J. E., Sacher, E., and Wertheimer, A.M., Applied Surface Science, 44, 165, 1990; [3] Carlsson, C.M.G., and Ström, G., Langmuir, 7, 2492, 1991; [4] Vander-Wielen, L.C., and Ragauskas, A.J., European Polymer Journal, 40, 477, 2004; [5] Vaswani, S., Koskinen, J., and Hess, D.W., Surface and Coatings Technology, 195, 121, 2005; [6] Vander Wielen, L.C., Őstenson, M., Gatenholm, P., and Ragauskas, A.J., Carbohydrate Polymers, 65, 179, 2006; [7] Mahlberg, R., Niemi, H. E. M., Denes, F., and Rowel, R. M., International Journal of Adhesion and Adhesives, 18, 283, 1998; [8] Gaiolas, C., Costa, A. P., Nunes, M., Santos Silva, M. J., and Belgacem, M. N., Plasma Processes and Polymers, 5, 444, 2008; [9] Gaiolas, C, Belgacem, M. N., Silva, L., Thielemans, W., Costa, A.P., Nunes, M., and Santos Silva, M. J., Journal of Colloid and Interface Science, 330, 298, 2009; [10] Costa, A. P. , PhD thesis, UBI, 2001.

R-2500

PT-2500

R-5000 R-7500 R-10000 R-20000

PT-20000 PT-10000 PT-7500 PT-5000

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Anaerobic biodegradation of spent brewery grains and aromatic compounds

I.C. Gonçalves 1, A. Fonseca1, A.M. Morão1, H.M. Pinheiro2, A.P. Duarte1 and M.I. Ferra1

1University of Beira Interior, Chemistry Department, R. Marquês D’Avila e Bolama, 6200 - Covilhã, Portugal 2 Centre of Biological and Chemical Engineering, Technical University of Lisbon, Av. Rovisco Pais – 1049-001 Lisbon, Portugal Abstract Anaerobic biodegradation of spent brewery grains (SBG) was investigated in the presence of an azo dye (Acid Orange 7 - AO7). Specific methanogenic activity (SMA) tests were carried out to assess the influence of the dye AO7. Values of specific methanogenic activity ranged from 0.41±0.01 to 2.75±0.01 Lbiogás / gSSV.d depending on the test conditions. A decrease on SMA values in the presence of dye was in general observed, suggesting that possible inhibitory effects should be involved. A high colour removal (87%±2%) was meanwhile attained, which could be explained by adsorption in tandem with biotic reductive cleavage of dye azo bond mechanisms. Results indicate that raw SBG is prone to biodegradation under anaerobic regime making possible the bio-energetic valorization of this byproduct. Introduction Azo dyes are considered xenobiotic compounds and have been extensively used in the textile, food, cosmetics,

pharmaceutical, leather, paper printing and photographic industries. These compounds represent the major group (60 - 70%) of dyes currently manufactured. Aside from their negative aesthetic effects, certain azo dyes and, their biotransformation products have been shown to be toxic to aquatic life and mutagenic to humans. Their decolourisation my occur by cleavage of the azo bond, to which the colour is associated, via anaerobic degradation through an non-specific and presumably extracellular process, in which reducing equivalents from an external electron donor (biologically or chemically generated) are transferred to the dye 1,2,3. The main byproduct of brewing industry is rich in proteins, cellulose, hemicelluloses and lignin, among other constituents. BSG is structurally an heterogeneous matrix resulting from a mixture of barley grain husk, pericarp and fragments of endosperm. Its chemical composition depends on the time of harvest, barley type, adjuncts supplemented and process technology. This type of biomaterials has been used as a low-value cattle food, as biosorbent and nowadays its potential as feedstock for bioethanol production has also been investigated 4. However innovative ways for value-added end-uses of SBG are also being searched. In the present work anaerobic biodegradation of SBG and its potential as resource for biogas was studied. Simultaneously the possibility of removal of xenobiotics was assessed.

Materials and Methods Raw material The spent brewery grains, SBG, used in the experiments

have the following composition (% dry weight, w/w): 24% protein, 60% fibre, 10% ashes and moisture and 6% lipids. It was gently supplied by a brewery from Lisbon region. Anaerobic biomass Anaerobic biomass was collected from two mesophilic lab-scale continuous reactors, fed with a synthetic wastewater. Dye Azo dye Acid Orange 7 (Figure 1) was purchased from Sigma-Aldrich (Germany). Analyses Colour was measured spectrophotometrically with Helios Alpha spectrophometer (Unicam, UK.) at the maximum visible absorbance wavelength of the dye (482 nm for AO7). Absorbance at this wavelength was correlated with dye concentration and used to quantify decolourisation. Suspended solids (SS), volatile suspended solids (VSS) and pH in liquid samples were determined according to Standard procedures (APHA, 2005). Anaerobic activity assay The specific methanogenic activity (SMA) tests were performed in duplicate, in bottles of 250 ml capacity sealed with rubber septa. After washing with buffer phosphate solution (Na2HPO4 and NaH2PO4) in order to remove residual substrate, sludge samples were transferred to incubation flasks. After 12 h of incubation, SBG was supplemented and the assay bottles were then flushed with N2 and incubated in the dark at 35 2oC with magnetic stirring. Azo dye was added together with the basal medium (60 mg l-1 resulting dye concentration). The OxiTop Control sensor (WTW, Germany) was used to measure the biogas pressure in the bottle headspace, and the specific methanogenic activity could then be determined.

Figure 1 – Chemical structure of dye Acid Orange 7

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Results and Discussion For raw SBG SMA values tend to be higher in mesophilic regime if calculated in the first 24h running time. For long-lasting reactions a sharp decrease in SMA values is observed (Table 1), indicating that reaction rate tends to decrease. This could be due to the presence of multiple substrates, leading to changes in reaction rates. In general the presence of dye AO7 seems to lower SMA results, suggesting a possible inhibition of the system. Cumulative biogas production curves (Figure 2) corroborated the idea that azo dye introduces an inhibitory effect, since results obtained in the presence of AO7 display lower values than those got for anaerobic degradation of SBG. In average the biogas production was of 15 mLbiogas/(gVSS.d), value that lowered to 8-10 mLbiogas/(gVSS.d) in the presence of dye.

Table 1 – Range of SMA values obtained for tests containing raw SBG performed with anaerobic biomass

Specific Methanogenic Activity (Lbiogas/(gVSS.d))

Substrate Mesophilic

SBG 0.56±0.06 - 2.40 ±0.00

SBG + AO7 0.41±0.01 - 2.40±0.20

As shown in Figure 2 notorious differences in cumulative curves of biogas for SBG+AO7 were registered, whereas for SBG values remained in general higher.

Figure 2 - Examples of time courses of cumulative biogas production for mesophilic cultures fed with SBG - spent brewery grains and SBG in the presence of AO7 - dye. Colour removal was in average of 87±2% for anaerobic mesophilic degradation tests performed in the presence of SBG. Considering that biosorption and reduction of azo bond are probably the main mechanisms subjacent to AO7 removal a better understanding of them would be helpful.

Figure 3 - Examples of UV-visible spectra of dye AO7 in the beginning and at the end of experiments with SBG - spent brewery grains UV-visible spectra of AO7 (Figure 3) show markable alterations with an almost complete elimination of the peak in the visible region (482nm) and slight increase of absorbance in the UV region, probably due to the presence of some intermediates. Conclusions SBG could work as adsorbent as well as an electron shuttle in the dye removal mechanism. Anaerobic biomass also can undergo adsorption and reductive mechanisms and both together could play a promising role on degradation of xenobiotics.

References 1. Brás R., Ferra M.I.A, Pinheiro H.M. and Gonçalves

I.C. (2001). Batch tests for assessing decolourisation of azo dyes by methanogenic and mixed cultures. Journal of Biotechnology, 89, 155-162.

2. Brown D. and Hamburguer B. (1987). The degradation of dyestuffs: part III – investigations of their ultimate degradability. Chemosphere, 16, 1539-1553.

3. Carliell C.M., Barclay S.J. and Buckley C.A. (1996). Treatment of exhausted reactive dyebath effluent using anaerobic digestion: laboratory and full-scale trials. Water SA, 22, 3, 275-233.

4. Silva J.P, Sousa S., Rodrigues J., Antunes H., Porter J.J., Gonçalves I., Ferreira-Dias S. Adsorption of acid orange 7 in aqueous solutions by spent brewery grains, Separation and Purification Technology, 2004, 40: 309-315.

Acknowledgements

The authors are grateful for the financial support from the research Unit of Textile and Paper Materials, Fundação para a Ciência e Tecnologia (FCT), Portugal

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1

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3.5

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Wavelenght (nm)

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Estabilidade e especiação de complexos metálicos de L-lisina em soluções de cloreto de potássio

E. M. J. Catalão, J. R. da Graça UMTP e Departamento de Química, Universidade da Beira Interior, 6201-001 Covilhã, Portugal

Resumo Realizaram-se estudos de estabilidade e especiação em soluções aquosas de L-lisina (Lys) e alguns iões metálicos (M), cobre (II), cobalto (II) e níquel (II) utilizando-se como método a potenciometria directa na forma de titulações potenciométricas. As constantes de formação globais das espécies complexas Mm(Lys)lHh foram determinadas a 30 ºC em soluções aquosas de cloreto de potássio 0,1 mol dm-3. A calibração do eléctrodo foi realizada por titulação potenciométrica de um ácido forte com uma base forte. A padronização da solução titulante.olução de hidróxido de potássio em cloreto de potássio, foi realizada por titulação potenciométrica de uma solução padrão de hidrogenoftalato de potássio. Os pontos finais das titulações foram determinados pelo método de Gran.

A análise dos valores experimentais dos βmlh mostrou

que a L-lisina se coordena com os iões metálicos Cu(II), Ni(II) e Co(II), formando iões complexos do tipo M(Lys) e M(Lys)2, e a sua estabilidade, em função do pH, é significativamente afectada pela presença destes iões metálicos. Introdução A compreensão detalhada das interacções entre ligandos e metais de transição em fluidos biológicos não é tarefa fácil devido à baixa concentração das espécies envolvidas nos equilíbrios químicos altamente selectivos e de grande labilidade. O conhecimento das constantes de formação globais e da interacção entre iões metálicos e aminoácidos em ambientes de força iónica controlada é fundamental para a compreensão do funcionamento do metabolismo das biomoléculas em sistemas vivos, uma vez que a sua estabilidade é grandemente afectada pela formação de complexos metálicos e pelo pH do meio[1]. Com o presente trabalho pretendeu-se estudar a formação e estabilidade de complexos metálicos entre a L-lisina e o cobre (II), o níquel (II) e o cobalto (II), em soluções aquosas de cloreto de potássio, determinar as constantes de formação globais molares das espécies mais importantes formadas nos equilíbrios químicos e realizar estudos de especiação química. A lisina é um aminoácido que não apresenta riscos para a saúde. Possui sim, uma grande vantagem, pois quando tomada juntamente com vitaminas e minerais resulta num aumento da densidade óssea em crianças com idades compreendidas entre os 6-12 anos[2]. De um modo geral praticamente todos os metais têm de um modo ou de outro importância no vital para o normal funcionamento dos sistemas biológicos,. Em particular o cobre actua ao nível do sistema digestivo, do sistema circulatório e do sistema nervoso central[3-5]. O níquel

parece ser essencial para os seres vivos e em particular para os humanos. Este metal foi ainda detectado em enzimas de bactérias e plantas. Apesar de essencial, o níquel pode causar diversos problemas à saúde humana, sendo mesmo em certas circunstâncias um veneno forte. Inalar partículas de níquel aumenta os riscos de cancro pulmonar e cancro nasal. Também as plantas são muito sensíveis à presença de níquel, variando a resistência a este elemento de planta para planta. Algumas toleram bem a presença do níquel enquanto outras morrem rapidamente em solos contaminados[6]. O cobalto é essencial a todos os animais incluindo os seres humanos. É um constituinte fundamental da cobalamina (vitamina B12). Uma deficiência grave de cobalto provoca anemia e pode originar desordens letais nos organismos[7]. O cobalto é um metal pesado que possui muitos perigos para a saúde, tendo como principais efeitos, quando inalado, garganta irritada, falta de ar, entre outros; estes sintomas acentuam-se quando a ingestão é prolongada e em grandes quantidades[8]. A seguir ao níquel e crómio o cobalto é a maior causa de “dermatitis de contacto” e é considerado cancerígeno[9]. Métodos O método utilizado neste trabalho foi a potenciometria directa, na forma de titulações potenciométricas do tipo ácido-base. O tratamento de resultados foi realizado com um conjunto de programas concebidos fundamentalmente para este fim, o programa HySS[10], utilizado na simulação dos ensaios experimentais e em estudos de especiação química, o programa GLEE[11], utilizado na calibração dos eléctrodos combinados de vidro, e o programa Superquad, utilizado na selecção de espécies e na determinação das constantes de formação globais das espécies complexas formadas nos equilíbrios[12,13]. Para cada sistema em equilíbrio construiu-se um modelo formado pelas espécies químicas m l hM L H que nos

pareceram ser as mais prováveis formarem-se nos equilíbrios. Na equação 1 representam-se as equações de formação destas espécies:

⎯⎯→+ + ←⎯⎯ m l hmM lL hH M L H (1)

No presente modelo mlh representa a espécie química

m l hM LH formada nos equilíbrios à qual se atribuiu uma

constante de estabilidade global, βmlh , definida na

equação 2:

[ ] [ ] [ ] [ ]= βm l h

m l h mlhM L H M L H (2)

A convergência do modelo foi analisada com o programa Superquad desenhado especialmente para este efeito. Este programa utiliza o método iterativo em conjunto com o

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método dos mínimos quadrados para realizar a selecção de espécies e assim determinar as constantes de formação globais. O processo iterativo é iniciado atribuindo-se valores iniciais às constantes de formação globais que queremos refinar à força iónica e à temperatura dos ensaios e com os dados experimentais das titulações e dos balanços de massa da equação 3:

[ ] [ ] [ ] [ ]

[ ] [ ] [ ] [ ]

[ ] [ ] [ ] [ ]−

= + × β

= + × β

+ = + × β

m l h

M mlh

m l h

L mlh

m l h1H w mlh

c M m M L H

c L l M L H

c K [H] H h M L H

(3)

onde KW representa o produto iónico da água à mesma força iónica, com o mesmo sal inerte [14] e a mesma temperatura do ensaio, cM representa a concentração total.

do reagente M e [ ]M a concentração de equilíbrio de M

livre em solução. Nestas equações omitiram-se as cargas das espécies iónicas para simplificação do texto escrito.

Parte Experimental Material e ensaios experimentais – A aquisição automáticas de dados foi realizada com uma interface Molspin ligada a um computador que controlava uma bureta automática constituída por um motor axial ligado a um parafuso que faz accionar uma seringa de Hamilton de 0,5 cm3. Com a interface mediram-se os potenciais de células (±0,1 mV), os incrementos de volume de titulante adicionado às soluções (±0,00002 cm3) e a temperatura dos ensaios (±0,5 ºC). Cada ensaio experimental consistiu num conjunto de três titulações potenciométricas: 1-padronização do titulante; 2-calibração dos eléctrodos; e 3-titulação potenciométrica dos sistemas metal-lisina-protão. Cada ensaio foi repetido seis vezes. Os ensaios realizaram-se numa célula de paredes duplas onde se titularam 10 g de solução. O potencial de célula foi medido simultaneamente com dois micro eléctrodos combinados de vidro da Metrohm, referência 6.0234.100, ligados em dois canais distintos da interface Molspin. A temperatura dos ensaios foi mantida constante a (30,0±0,5) ºC. Soluções – Todas as soluções foram preparadas em massa-volume e em meio aquoso de cloreto de potássio 0,1 mol dm-3, para controlar e fixar a força iónica do meio. A água utilizada na preparação das soluções foi bidestilada num bidestilador Double D-ionstill e desionizada num desionizador Millipore Milli-Q Plus 185. Preparam-se soluções de hidrogenoftalato de potássio 3 mmol dm-3 (utilizadas na padronização do titulante), soluções de ácido clorídrico 10 mmol dm-3

(utilizadas na calibração dos eléctrodos) preparadas por diluição do conteúdo de ampolas Titrisol da Merck, soluções de hidróxido de potássio 0,2 mol dm-3 (titulante) preparadas por diluição do conteúdo de ampolas Titrisol da Merck, soluções de lisina 1,5 mmol dm-3 acidificadas com ácido clorídrico 3 mmol dm-3 (para a determinação das constantes de formação globais da lisina) e soluções de metal-lisina contendo L-lisina 1,5 mmol dm-3 e cloreto do metal (cobre (II), níquel (II) e cobalto (II)) 0,25 mmol dm-3 e acidificadas com ácido clorídrico 3 mmol dm-3. Todos os solutos sólidos foram secos durante cerca de vinte e quatro horas numa estufa a 110 ºC excepto a L-lisina que foi seca a 50 ºC. Erro da bureta – O erro da bureta, ıV, é um parâmetros importante a controlar pois dele e do erro do petencial ıE depende a qualidade da convergência do modelo aos dados experimentais. A bureta (seringa de Hamilton) foi calibrada, utilizando-se a água como padrão de calibração. Foram realizados vinte ensaios de incrementos volume de 0,004 cm3 entre 0 e 0,5 cm3. O erro da bureta foi determinado pelo valor do erro padrão desta análise e deu o valor ±0,00002 cm3. Pesagens - As massas dos solutos sólidos e das soluções aquosas foram medidas numa balança Sartorius XM 1000 P de precisão ±0,05 % e as massas das soluções foram medidas numa balança Mettler AE 260 Deltarange de precisão ±0,0001 g. Resultados e Discussão Na Tabela 1 resume-se a selecção de espécies realizada nos sistemas M-Lys-H e indicam-se os valores das respectivas constantes de formação globais obtidas em soluções aquosas de cloreto de potássio 0,1 mol dm-3 a 30 ºC. Com os dados das constantes de formação globais da Tabela 1 e com as equações 2 construíram-se os diagramas da Figura 1, que representam a especiação das espécies estáveis formadas nos equilíbrios. Nos diagramas da Figura 1 podem-se tirar algumas conclusões sobre a influência do pcH e dos iões metálicos Cu(II), Ni(II) e Co(II), na estabilidade da L-lisina livre e das formas protonadas. Por exemplo, no intervalo de pcH compreendido entre 2 e 4: -no sistema Lys-H LysH2 e LysH3 são estáveis, LysH e Lys livre não são se formam e a LysH2 é a espécie predominante; -no sistema Cu-Lys-H forma-se LysH2 e LysH é a espécie predominante por influência da formação da espécie Cu(Lys)2 a pcH compreendido entre 4 e 11; -no sistema Ni-Lys-H forma-se exclusivamente LysH3 e a espécie LysH2 aparece estável a pcH entre 6 e 11 por influência da formação do complexo Ni(Lys) que se forma na região alcalina acima de pcH 9; -no sistema Co-Lys-H froma-se exclusivamente LysH2, sendo que LysH aparece estável a pcH 7 e 11 por influência da formação do complexo Co(Lys) a partir de pcH 6.

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Tabela 1 – Valores experimentais de log βmlh das espécies mais importantes formadas nos sistemas M-Lys-H a 30 ºC e em soluções de cloreto de potássio 0,1 mol dm-3

Sistema Selecção de espécies log βmlh±DP

011 11,130±0,034

012 20,630±0,032 Lys–H

013 22,500±0,086

011 9,700±0,017

110 7,760±0,084 Cu–Lys–H

120 14,10±0,10

012 20,410±0,037

013 28,400±0,046 Ni–Lys–H

110 5,300±0,031

011 10,430±0,035

012 19,600±0,048 Co–Lys–H

110 6,970±0,087

LysLysHLysH2

LysH3

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LysH2 Cu(Lys)2

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Figura 1 – Percentagem de espécie formada em função do pcH nos sistemas L-lisina e M–Lys–H (M=Cu(II), Ni(II) e Co(II)), em soluções aquosas de cloreto de potássio 0,1 mol dm-3 a 30 ºC.

Referências [1] E. J. Underwood, Trace Elements in Human and

Animal Nutrition, 4th ed., Academic Press, New York, 1977.

[2] A. Quintas, A. P. Freire, M. J. Halpern, “Bioquimica Organização molecular da vida”; Lidel, 2008.

[3] B. L. O’Dell, “Trace Elements in Human Health and Disease”, Vol. I, A. S. Prasad and D. Oberleas, Eds., 1976, pp. 391-413

[4] P. McDonald, R. A. Edwards, and J. F. D. Greenhalgh, Animal Nutrition, 4th ed., John Wiley, New York, 1988.

a)

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Electrochemical degradation of the amine 8-aminonaftalene-1-sulfonic acid: Influence of stirring and flow rate

S. Sobreira, M.J. Pacheco, L. Ciríaco, A. Lopes UMTP and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal

Abstract The influence of the hydrodynamic conditions of the experimental setup on the extent of the electrochemical degradation of an aromatic amine, 8-aminonaftalene-1-sulfonic acid, using as anode a boron-doped diamond (BDD) electrode was accessed. In the assays, two different electrochemical cells were used: a batch stirred cell (A), with a volume of 200 mL and a BDD anode of 17.5 cm2, and a batch with recirculation cell (B), with a BDD anode of 70 cm2 and connected to a tank of 30 L. Assays were performed at different stirring speeds for cell A and different re-circulating flow rates for cell B. Chemical oxygen demand (COD) and total organic carbon (TOC) tests were performed with the samples collected throughout the assays, as well as UV-Vis spectrophotometric measurements. For cell A, after 2 h assay, COD removals between 60 and 98% and TOC removals ranging from 40 and 65 % were attained. For the assays run with cell B, during 5 h, COD removals varied from 10 to 35%. The influence of the turbulence near the electrode’s surface in the thickness of the Nernst diffusion layer was also analysed. Introduction Aromatic amines are widely used in industrial textile processing [1,2] and as an intermediate in the production of dyes and various other chemicals [3]. They are toxic and with potential carcinogenic properties [4]. In particular, the aromatic amine known as aniline has been recognized as a high priority pollutant by the United States Environmental Protection Agency [5]. Due to these facts, European Community made a list of 22 dangerous aromatic amines and prohibited the use of azo dyes which, by reductive cleavage of one or more azo groups, may release one or more of those aromatic amines, in detectable concentrations, i.e., above 30 mg L-1 in the finished articles or in the dyed parts thereof and may not be used in textile and leather articles which may come into direct and prolonged contact with the human skin or oral cavity (CONSLEG: 1976L0769 — 16/03/2004). The aromatic sulfonated amines are also very dangerous pollutants, since they are very soluble in water and many of them resist to microbial degradation [6]. As a consequence of its low biodegradability, aromatic sulfonated amines have been found in wastewater as well as in surface waters [4]. Since biological treatments do not give a satisfactory answer in the degradation of the amines, it is necessary to find alternatives. Electrochemical oxidation of effluents containing persistent pollutants is an alternative that has received much attention in the last years due to its interesting characteristics, since it is a clean process, can operate at

low temperature and, in most cases, without adding any chemical and without sludge formation. Recently, the use of boron doped diamond (BDD) as anode material has proved to be very useful, since, besides its good mechanical and electrochemical stability, it has unique electrochemical characteristics, like large potential window for water decomposition [7], ability to produce hydroxyl radicals [8] poorly adsorbed on the electrode’s surface [9] and that can perform the simultaneously oxidation of the pollutants in the bulk of the solution. Therefore, BDD anodes are an excellent material for the oxidation of all kinds of organic pollutants [10]. In particular, the electro-oxidation of several amines has already been carried out with BDD anodes, at bench scale, with good degradation rate [11,12]. However, to scale-up the process to an industrial level, a better control of the mass transfer process during the electrochemical degradation is needed. The objective of this work is to study the influence of the hydrodynamic conditions on the mass transfer process during the anodic oxidation of a naftalenic amine, the 8-aminonaftalene-1-sulfonic acid (Figure 1), using BDD as anode material, in two different electrochemical cells: a small batch stirred cell and a pilot cell with re-circulating flow. Materials and Methods Two sets of electrochemical assays were run, using different experimental set-ups. The first one (A) consisted of an electrochemical cell, with a BDD anode of 17.5 cm2 area, purchased from Admant Technologies/CSEM, Switzerland, and the degradation was carried out in batch mode, for 2 h, at several stirring rates, using 200 mL of an aqueous 0.035 M Na2SO4 solution, containing 100 mg L-1

of the amine (purchased from Aldrich). A current density of 30 mA cm-2 was imposed by a laboratory power supply GW, model GPS-3O3OD. Three different stirring rates were tested 100 rpm (ST1), 300 rpm (ST3) and 500 rpm (ST5). Cell B was a DiaCel 196PVDF, with two monopol BDD electrodes (70 cm2 area), from Admant Technologies/ CSEM, Switzerland, used with a power supply DiaCell, PC-1500, that imposed a current density of 10 mA cm-2. These assays were performed in batch with recirculation mode, for 5 h, and a centrifugal pump, Wilo, Serie MHI, enabled the recirculation of the solution at the different flow rates tested. The composition of the solution was identical of that in cell A, but a volume of 30 L was used and recirculation flow rates of 250, 400, and 500 L h-1 were tested.

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All the electrochemical assays were performed in galvanostatic mode, and the amine degradation tests were followed by UV-Visible spectrophotometry, with absorbances being measured from 200 to 600 nm, using a UNICAM -Heλios-α UV/VIS spectrophotometer, by Chemical Oxygen Demand (COD) tests, using the closed reflux dichromate titrimetric method [13], and by Total Organic Carbon (TOC) determinations, performed in a Shimadzu TOC-VCPH apparatus.

SO3H NH2

Figure 1. Chemical structure of the amine 8-aminonaftalene-1-sulfonic acid. Results and Discussion COD analysis Figure 2 presents the experimental COD removal as a function of the assays’ duration, for the different experimental conditions tested with both electrochemical cells. As can be observed (Table 1), an increase in stirring rate or recirculation flow rate increases the medium mass transfer coefficients, kd, determined assuming that the electro-oxidation is diffusion controlled and the COD vary according to the equation [14]:

dk A t-

V0COD=COD e (1)

where COD0 refers to the initial COD, A, V and t are the area of the electrode, the volume of the solution and the time, respectively. In order to estimate the thickness of the Nernst diffusion layer, the diffusion coefficient, D, for the amine molecule was calculated using the Wilke and Chang equation [15]:

1/28

0.6m

(yM) TD 7.4x10

ηV−

= (2)

where y is an association parameter that accounts for hydrogen bonds in the solvent (2.6 for water), M is the solvent’s molecular weight, in g mol-1, T is the absolute temperature, in K, η is the solvent viscosity, in cP, and Vm is the molar volume, in mL mol-1. A molar volume of 148.6 cm3 was obtained with ACD/ChemSketch. If this value is used in eq. 2, the diffusion coefficient of the amine can be calculated as 8.5 x10-10 m2 s-1. With the DAmine and the different medium mass transfer coefficients, for the diffusion controlled processes, the thicknesses of the Nernst diffusion layer for the different experimental conditions were calculated (D/kd) and are presented in Table 1. TOC analysis The samples collected during the assays performed with cell A were analyzed for the total organic carbon content. Experimental results are presented in Figure 3. Although TOC removal rate increases with stirring speed, the

variation is less pronounced than that observed for COD removal rate, meaning that the electrochemical oxidation does not correspond to a complete mineralization.

Cell A 30 mA cm-2

t / min

0 15 30 45 60 75 90 105 120 135

CO

D /

CO

D0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

ST 1ST 3ST 5

Cell B 10 mA cm-2

t / h

0 1 2 3 4 5 6

CO

D /

CO

D0

0.4

0.6

0.8

1.0

1.2

250 L min-1

400 L min-1

500 L min-1

Figure 2. COD relative removal vs time for the electrochemical degradation of the amine performed in cell A, at different stirring rates, and in cell B, at different re-circulation flow rates. Amine initial concentration: 100 ppm; electrolyte: 0.035 M Na2SO4 aqueous solution.

Cell A 30 mA cm-2

t / min

0 15 30 45 60 75 90 105 120 135

TO

C/ T

OC

0

0.2

0.4

0.6

0.8

1.0

1.2

ST 1ST 3ST 5

Figure 3. TOC relative removal vs time for the electrochemical degradation of the amine performed in cell A, at different stirring rates. Amine initial concentration: 100 ppm; electrolyte: 0.035 M Na2SO4 aqueous solution.

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Ultraviolet-Visible spectrofotometry analysis In Figure 4 the UV-Vis spectra for some of the assays run with both electrochemical cells are depicted. In both cases, there is a regular removal of the absorbance with time. Absorbance removal also increases with stirring rate and with flow rate (data not shown). However, the decrease in absorbance depends on the wavelength. In fact, near 300 nm we can observe a slow removal of the absorbance, usually related with the formation of polymeric compounds that polarize the surface of the anode and prevents the anodic oxidation. This fact is more evident at low current densities and, in fact, it is more evident when the applied current density is 10 mA cm-2 (figure 4). Conclusions The electrochemical degradation of the acid 8-aminonaftalene-1-sulfonic was carried out in different hydrodynamic conditions, showing that an increase in turbulence near the electrode’s surface is a very important parameter and its control can be used to increase the rate of COD, TOC and absorbance removals. The good results obtained in assays run in the pilot cell, with 30 L of simulated effluent, show that electrochemical techniques are a promising method to treat real effluents, specially when a good control of the hydrodynamic conditions can lead to an increase in the efficiency of the energetic consumption.

Cell A ST5 30 mA cm-2

λ / nm200 250 300 350 400

Abs

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 min15 min 30 min45 min120 min

Cell B 500 L h-1 10 mA cm-2

λ / nm

200 250 300 350 400

Abs

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 h 1 h 2 h 3 h 4 h 5 h

Figure 4. Absorption spectra for the samples collected at different times for the electrochemical degradation of the amine performed in cell A and in cell B.

Table 1 – Values for the experimental mass tranfer coefficients, kd (eq. 1) and thicknesses of the Nernst diffusion layer for the electrochemical degradation of the amine performed in cell A, at different stirring rates, and in cell B, at different recirculation flow rates.

Experimental set-up Experimental conditions kd / 10 -5 m s-1

(eq. 1) δ / μm

ST 1 1.4 62

ST 3 1.4 59

Cell A

Stirring rate

ST 5 4.4 19

250 2.3 36

400 9.9 9

Cell B

Recirculation flow rate /

L h-1 500 9.9 9

References 1. Rieger, P.G, Meier, H.M., Gerle, M., Vogt, U., Groth,

T., and Knackmuss, H.J., J. Biotechnol., 94, 101–12, 2002.

2. Pandey, A., Singh, P., and Iyengar, L., Int. Biodeterior. Biodegrad., 59, 73, 2007.

3. Panizza, M., Brillas, E., and Comninellis, C., Application J. Environ. Eng. Managem., 18, 139, 2008.

4. Pinheiro, H.M., Touraud, E., and Thomas, O., Dyes Pigments, 61, 121-13, 2004.

5. EPA OPPT Chemical Fact Sheets, Aniline Fact Sheet; Support Document (CAS Nº 62-53-3), December 1994.

6. Alonso, M.C., and Barceló, D., Anal. Chim. Acta, 400, 211, 1999.

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7. Fryda, M., Herrmann, D., Schäfer, L., Klages, C.P., Perret, A., Haenni, W., and Comninellis, C., New Diam. Front. Carb. Technol., 9, 229, 1999.

8. Martínez-Huitle, C.A., and Ferro, S., Chem. Soc. Rev., 35, 1324, 2006.

9. Marselli, B., Garcia-Gomez, J., Michaud, P.A., Rodrigo, M.A., and Comninellis, C., J. Electrochem. Soc., 150, D79, 2003.

10. Panizza, M., and Cerisola, G, Electrochim. Acta, 51, 191, 2005.

11. Santos, V., Diogo, J., Pacheco, M.J., Ciríaco, L., Morão, A., and Lopes, A., Chemosphere, 79, 637-45, 2010.

12. Pacheco, M.J.A., Santos V., Ciríaco, L., and Lopes, A., J. Haz. Mat., 2010, accepted.

13. Eaton, A., Clesceri, L., Greenberg, A., Standard Methods for Examination of Water and Wastewater. APHA, AWWA, WEF, 21st Ed., Washington, 2005.

14. Rodrigo, M.A., Michaud, P.A., Duo, I., Panizza, M., Cerisola, G., and Comninellis, Ch., J. Electrochem. Soc., 148, 60 2001.

15. Reid, R.C., Prausnitz, J.M., and Poling, B.E., The Properties of Gases and Liquids. 4th Ed., McGraw-Hill International Editions, NY, 1988.

Acknowledgements The financial support of FCT, PDCT/AMB/59392/2004, PDCT/AMB/59388/2004, and Adamant Technologies are gratefully acknowledged.

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Antioxidant activities of extracts from Acacia melanoxylon, Acacia dealbata and

Olea europaea and alkaloids estimation Â. Luís 1, N. Gil 2, A. P. Duarte 1,3, M. E. Amaral 2,4

1Health Sciences Research Centre, 2Research Unit of Textile and Paper Materials, 3Faculty of Health Sciences, 4Department of Chemistry

University of Beira Interior Abstract The determination of the total amount of different classes of components is essential for the standardization of the plants. Polyphenols and particularly flavonoids are widely appreciated for their potential beneficial health effects, like antioxidant and anticarcinogenic. The aim of this study was to determine the antioxidant activity of extracts of some species of trees that grow in Portugal. The Folin-Ciocalteu’s method was used to determine total phenols while a colorimetric method with aluminum chloride was used for the determination of total flavonoids. Regarding the determination of antioxidant activity, DPPH assay and beta-carotene bleaching test were used. It was concluded that all the extracts presented relevant antioxidant activity and there was a positive linear correlation between antioxidant activity index and total phenolic content.

Introduction Some plants may become invasive in new areas, leading to profound changes in ecosystem processes, community structure and displacing native species. In most cases, first noticeable change in invaded areas is the loss of the plant biodiversity, due to the establishment of monocultures of invasive species [1]. Different acacia species are aggressive invaders that affect ecosystem integrity worldwide. Acacia dealbata and Acacia melanoxylon, the most invasive Australian acacias in southern Europe, particularly in Portugal, invades farmland, and autochthonous forest, establishing monocultures and modifying the ecosystem structure. This invasive species has become a serious environmental problem because they displace the indigenous plant species [1]. In other way, olive tree (Olea europaea) is one of the most important trees in Mediterranean countries, were they cover ~8 million ha, accounting for almost 98% of the world harvest [2]. This demonstrates the great economic and social importance of this crop and the possible benefits to be derived from utilization of any of its by products [3]. The raw material from the pruning of olive trees has low cost and high availability because it is concentrated in the olive oil production centers, but at present a very limited productivity is obtained from it because the main interest is concentrated in the olive oil production and not in the reuse of its by products. Several studies dealing with the chemical composition of the olive fruits and their oil have been carried out [4]; however,

only a few works have been focused on the isolation and identification of some compounds found on olive extracts [4]. Because of its nutritional and biological characteristics, virgin olive oil is one of the most important components of the Mediterranean diet and local agriculture. The traditional Mediterranean diet, which consists of fruits, vegetables, cereals, legumes and fish, is thought to represent a healthy lifestyle; especially the incidence of several cancers, including colorectal cancer, is lower in Mediterranean countries compared to Northern Europe [5]. Olives and olive derived are an important part of this diet and are recognized as a valuable source of natural phenolic antioxidants. In fact, an increasing number of epidemiologic and experimental studies report that the olive oil may have a role in the prevention of coronary heart disease, cognitive impairment, e.g., Alzheimer’s disease, protective effects against of the cancer of the colon, breast and ovary, diabetes accompanied by hypertryglyceridemia and inflammatory and autoimmune diseases, such as rheumatoid arthritis [5]. Also, olive oil has been shown to reduce low-density lipoprotein (LDL) oxidisability in the post prandial state. These beneficial health effects of olive oil are ascribable to monounsaturated, and low unsaturated fatty acids and a number of phenolic compounds [5]. Plant-derived natural chemicals, known as secondary metabolites, are effective in their roles of protection, adaptation and pollination. Secondary metabolites are mainly used in food, pharmaceutical, chemical, cosmetic industries and agriculture. Plant-derived natural products are abundant in nature. Many of them exhibit numerous biological activities and some can be employed as food additives. Synthetic antioxidants have been used in the food industry since the 1940s, but trends in many health-related industries tend to shift preferences to natural sources. Therefore, investigation of natural antioxidants has been a major research interest for the past two decades as many research groups and institutions have been screening plant materials for possible antioxidant properties [6-8]. Antioxidants also play important role preventing oxidative deterioration of food and indirectly eliminating radicals from it. Synthetic antioxidants such as butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate and tertiary butylhydroquinone are often used in foods to prevent oxidative degradation. Application of synthethic antioxidants in foods is negatively perceived by consumers due to safety and health effect. Moreover, need to understand how different antioxidant compounds work, what components may form an antioxidant system, stimulate search for antioxidants,

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particularly from plant sources. It has also been proposed that antioxidant activity of plant origin components can be mainly ascribed to the presence of phenolic compounds [7,9]. No single chemical component is responsible for the medicinal properties of plant-based drugs, and their synergic action or bioenhacement is due to the presence of other chemical substances in the plant material. Therefore, the determination of the total amount of different classes of components is essential for the standardization of the plants [10]. Alkaloids are low molecular weight nitrogen-containing substances with characteristic toxicity and pharmacological activity. These properties, which have traditionally been exploited by humans for hunting, execution and warfare, have also been used for the treatment of disease [11]. As alkaloids have therapeutic efficacy and bioenhancing properties, the estimation of total alkaloids in plants bearing alkaloids and formulations that contain them as therapeutic agents becomes essential [10]. The purpose of this work was to determine the phenolic, flavonoid and alkaloid contents of the ethanolic, methanolic, acetone and hydroalcoholic extracts of Olea europaea, Acacia melanoxylon and Acacia dealbata, and then try to correlate it with antioxidant activity of same extracts. The Folin-Ciocalteu’s method was used for the determination of total phenols, a colorimetric method with aluminum chloride was used in the determination of total flavonoids and Dragendorff’s reagent method was used to alkaloid estimation. The methods of DPPH (2,2-diphenyl-1-picryl-hidrazil) and beta-carotene bleaching test were used to assess the antioxidant activity of extracts. Materials and Methods Plant material Aerial parts (wood, bark and leaves) of the trees (Olea europaea, Acacia melanoxylon and Acacia dealbata) were collected in Serra da Estrela. Plant materials were air-dried at room temperature during 3 months and reduced to coarse powder (< 1 mm) using a laboratory cutting mill. A voucher specimen of all species of trees has been deposited in the Biology Laboratory of Health Sciences Research Centre, University of Beira Interior. Extraction process Ethanolic, methanolic and acetone extracts were carried out with Shoxlet apparatus until the solvent became colorless, using 100 g of raw material and 1000 mL of solvent. Hydroalcoholic extractions, water/ethanol 50/50 (v/v), were performed by refluxing, using 100 g of plant samples during 45 minutes with 1000 mL of solvent. The extract solutions were filtered under vacuum using a crucible of porosity 2 and then distilled under vacuum to remove the solvents to a final volume of 150 mL. Then, 5 mL of each extract was diluted in 45 mL of methanol. Aliquots (50 mL) of the extracts were removed for subsequent evaporation to dryness for the calculation of extraction yield.

Total phenolic compounds determination The phenols were determined by Folin-Ciocalteu’s colorimetric method. The methanolic solutions of each extract (50 μL) or gallic acid (standard phenolic compound) were mixed with 450 μL of distilled water and then 2.5 mL of Folin-Ciocalteu’s reagent 0.2 N (diluted with distilled water) was added. The mixtures were allowed to stand for 5 minutes, and then 2 mL of aqueous Na2CO3 (75 g/L) was added. After incubation of these reaction mixtures (90 minutes / 30 C) the total phenols were determined by colorimetry at 765 nm. The standard curve was prepared using 500, 400, 350, 325, 300, 250, 225, 200, 150, 125, 100 and 50 mg/L solutions of gallic acid in methanol (y=0.0009x; R2=0.9875). Total phenol values were expressed as gallic acid equivalents (mg/g of dry mass), which is a common reference compound for phenolic compounds [12,13]. Flavonoids determination Aluminum chloride colorimetric method was used for flavonoids determination according to Pourmorad, F. et al, (2006). Each extract (500 μL) in methanol was separately mixed with 1.5 mL of methanol, 0.1 mL of 10 % aluminum chloride, 0.1 mL of 1 M potassium acetate and 2.8 mL of distilled water. This solution remained at room temperature for 30 minutes; the absorbance of the reaction mixture was measured at 415 nm using a spectrophotometer. The calibration curve was constructed by preparing eight quercetin solutions at concentrations ranging from 12.5 to 200 μg/mL in methanol (y=0.0071x; R2=0.9979). Total flavonoid values were expressed as quercetin equivalents (mg/g of dry mass), which is a common reference compound for flavonoids [13]. Alkaloids estimation The alkaloids estimation was performed by spectrophotometric method of Dragendorff’s reagent as it was described by Sreevidya, N. et al, (2003). Briefly, 10 mL amount of each crude extract was centrifuged over 10 minutes (3000 rpm) to remove residual suspended particles and then 5 mL of the supernatant were mixed with 1 mL of HCl 0.1 N, 2.5 mL of Dragendorff’s reagent was added to the previous mixture, and after precipitation the precipitate was centrifuged over 5 minutes (3000 rpm). The precipitate was further washed with 2.5 mL of ethanol. The filtrate was discarded and the residue was then treated with 2.5 mL of disodium sulfide solution (1% w/v). The brownish black precipitate formed was then centrifuged (5 minutes, 3000 rpm). This residue was dissolved in 2 mL of concentrated nitric acid, with warming if necessary; this solution was diluted to 10 mL in a standard flask with distilled water and 1 mL was then pipetted out and mixed with 5 mL of thiourea solution (3% w/v). The absorbance of this solution was measured at 435 nm against a blank containing 1 mL of concentrated nitric acid and 2.5 mL of thiourea solution (3% w/v). The standard curve was prepared using 750, 500, 400, 250, 200, 150 and 100 mg/L solutions of pilocarpine

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nitrate in HCl 0.1N (y=0.0012x-0.1044; R2=0.9851). Alkaloid contents were expressed as pilocarpine nitrate equivalents (mg/g of dry mass) [10]. Evaluation of antioxidant activity: a) DPPH scavenging assay The antioxidant activity of the extracts and standards (gallic acid, quercetin, rutin and trolox) was determined by the radical scavenging activity method using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) as it was described by Scherer, R. et al, (2009). Briefly, about 0.1 mL aliquots of methanolic solutions of the extracts or standards at different concentrations were added to 3.9 mL of a DPPH methanolic solution. Three DPPH solutions were tested, 0.2000, 0.1242 and 0.0800 mM, prepared by dissolving 39.4, 24.5 and 15.8 mg in 500 mL of methanol, respectively. These concentrations were selected due to the linearity range of DPPH solutions: above 0.2 mM the concentration is very high, and below 0.5 mM the color is very weak having a limited range of absorbance reading. The blank sample consisted in a solution of 0.1 mL of methanol mixed with 3.9 mL of DPPH. After a 90 min incubation period at room temperature in the dark, the absorbance was measured at 517 nm. The radical scavenging activity was calculated as follows: I % = [(Abs0 - Abs1) / Abs0] × 100, where Abs0 was the absorbance of the blank and Abs1 was the absorbance in the presence of the test sample at different concentrations. The IC50 (concentration providing 50% inhibition of DPPH radicals) was calculated graphically using a calibration curve in the linear range by plotting the extract concentration vs the corresponding scavenging effect. The antioxidant activity was expressed as the antioxidant activity index (AAI), calculated as follows: AAI = (final concentration of DPPH - µg.mL-1)/(IC50-µg.mL-1) [14]. Thus, the AAI was calculated considering the mass of DPPH and the mass of the tested sample in the reaction, resulting in a constant for each sample, independent of the concentration of DPPH and sample used. In this work it was considered that shrub extracts showed poor antioxidant activity when AAI < 0.5, moderate antioxidant activity when AAI between 0.5 and 1.0, strong antioxidant activity when AAI between 1.0 and 2.0, and very strong when AAI > 2.0, according to Scherer, R. et al, (2009). Assays were carried out in triplicate and all the samples and standard solutions, as well as the DPPH solutions, were prepared daily [14]. b) Beta-carotene bleaching test This test was also used to evaluate the antioxidant activity of the extracts. After preparation of beta-carotene solution (20 mg/mL in chloroform), 20 μL of it was added to 40 μL of linoleic acid, 400 mg of Tween 40 and 1 mL of chloroform. This mixture was then evaporated at 45 ºC for 5 minutes by using a rotary vacuum evaporator to remove chloroform and immediately diluted with 100 mL of oxygenated distilled water. The water was added slowly

to the mixture and vigorously agitated to form an emulsion. About 5 mL of the emulsion were transferred into test tubes containing 300 μL of extracts in methanol at different concentrations. About 5 mL of the emulsion and 300 μL of samples in methanol were used as control. Standard butylated hydroxytoluene (BHT) in methanol, at the same concentration as samples, was used as reference. The tubes were then gently shaken and placed at 50 ºC in a water bath for 2 hours. The absorbances of the extracts, standard and control were measured at 470 nm, using a spectrophotometer, against a blank consisting of an emulsion without beta-carotene. The measurements were carried out at initial time (t=0) and at final time (t=2). All samples were assayed in duplicate. The antioxidant activity was measured in terms of percentage of inhibition of beta-carotene’s oxidation by: % Inhibition=(Abst=2

sample – Abst=2

control)/( Abst=0control – Abst=2

control) Where Abst=2 was the absorbance of the sample or control at final time of incubation and Abst=0 was the absorbance in the control at initial time of incubation [7].

Results and Discussion The extract that displayed the highest concentration of total phenols is the hidroalcoholic extract of Acacia dealbata. Simultaneously this extract had the greatest antioxidant activity, ie, this extract is that required the lowest concentration to promote 50% of inhibition (IC50) and higher value of AAI, which classifies the activity of this extract as being a very strong antioxidant. The specie that has the highest amount of phenols is Acacia dealbata. Comparing all the extracts of same species with different solvent, it is concluded that the solvent does not appear to influence the concentration of the extracted phenols. Acacia melanoxylon is the specie with more flavonoids, and of all the extracts, the extract that had the highest concentration in total flavonoids is the acetone extract of Acacia melanoxylon. Regarding to the alkaloids determination it is possible to conclude that the solvent more appropriate to their extraction is acetone. The extract that had the highest concentration in alkaloids is the extract of Acacia dealbata. It can be observed that the content of phenolics in the extracts correlates with their antiradical activity. Those results suggest that the phenolic compounds contribute significantly to the antioxidant capacity of the investigated species. Olea europaea is the specie which antioxidant activity measured with beta-carotene bleaching test is lower contrariwise Acacia dealbata shows great potential to inhibit the oxidation of linoleic acid. Comparing all solvent studied, it appears that the mixture of water/ethanol is most suitable for the extraction of compounds with the ability to inhibit lipid peroxidation.

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Table 1 – Extraction yield, total phenolic content, flavonoids, alkaloids and antioxidant properties of extracts of Olea europaea, Acacia

melanoxylon and Acacia dealbata.

Extracts Tree Extraction

Yield (%)*

Total phenolic content (Gallic Acid

Equivalents mg/g of

dry mass)*

Flavonoids

(Quercetin

Equivalents

mg/g of dry

mass)*

Alkaloids

(Pilocarpine

nitrate

Equivalents

mg/g of dry

mass)*

IC50

(mg/L)* AAI*

Antioxidant

Activity

Ethanolic

Olea europaea 13.3 ± 0.78 115.89 ± 0.11 31.60 ± 0.51 2.96 ± 0.27 44.08 ± 0.47 1.08 ± 0.01 Strong Acacia

melanoxylon 14.05 ± 0.08 127.33 ± 0.41 45.82 ± 086 10.12 ± 0.94 29.72 ± 1.58 1.66 ± 0.11 Strong

Acacia dealbata 6.75 ± 0.03 243.80 ± 2.50 18.37 ± 0.23 5.82 ± 0.20 13.82 ± 0.32 3.43 ± 0.10 Very strong

Hidroalcoholic

Olea europaea 14.69 ± 1.80 112.01 ± 2.46 18.75 ± 0.11 4.82 ± 0.09 49.97 ± 1.58 0.95 ± 0.03 Moderate Acacia

melanoxylon 15.41 ± 0.66 138.76 ± 1.23 22.21 ± 1.09 4.15 ± 0.16 22.49 ± 0.64 2.09 ± 0.06 Very strong

Acacia dealbata 9.51 ± 0.68 290.65 ± 5.87 13.46 ± 0.19 5.81 ± 0.34 11.85 ± 0.20 3.98 ± 0.09 Very strong

Methanolic

Olea europaea 16.31 ± 1.74 105.30 ± 1.19 27.40 ± 0.29 2.76 ± 0.36 48.77 ± 2.35 0.98 ± 0.04 Moderate Acacia

melanoxylon 11.88 ± 1.36 112.03 ± 2.32 43.47 ± 0.87 18.18 ± 0.42 29.32 ± 0.79 1.59 ± 0.05 Strong

Acacia dealbata 7.68 ± 0.39 241.81 ± 2.28 16.89 ± 0.03 14.88 ± 0.56 13.49 ± 0.20 3.45± 0.06 Very strong

Acetone

Olea europaea 6.3 3± 0.29 116.55 ± 7.11 48.70 ± 2.25 18.87 ± 0.55 54.23 ± 2.36 0.91 ± 0.03 Moderate Acacia

melanoxylon 5.68 ± 0.15 100.10 ± 4.74 99.24 ± 2.57 13.70 ± 0.77 45.97 ± 1.06 1.05 ± 0.02 Very strong

Acacia dealbata 3.26 ± 0.33 203.1 0± 3.84 21.70 ± 3.12 19.46 ± 0.92 15.49 ± 0.99 3.11 ± 0.20 Very strong Trolox - - - - - 8.38 ± 0.13 6.62 ± 0.10 Very strong

Gallic acid - - - - - 2.23 ± 0.02 22.77 ± 0.25 Very strong Rutin - - - - - 10.66 ± 0.39 4.90 ± 0.21 Very strong

Quercetin - - - - - 4.32 ± 0.39 12.17 ± 1.71 Very strong

* Results in terms of mean ± standard deviation

Conclusions All the studied extracts presented antioxidant activity. Alkaloids determination shows that all the studied extracts have significant amounts of these compounds. There was a positive linear correlation between antioxidant activity index and total phenolic content for all the extracts. It is noteworthy that there is no correlation between flavonoids and antioxidant activity of the extracts.

References 1. Lorenzo, P., Rodrígues-Echeverría, S., González, L.,

Freitas, H., Applied Soil Ecology, 44, 245, 2010; 2. Ferreira, I., Barros, L., Soares, M., Bastos, M.,

Pereira, J., Food Chemistry, 103, 188, 2007; 3. Guinda, Á., Albi, T., Pérez-Camino, M., Lanzón, A.,

European Journal of Lipid Science and Technology, 106, 22, 2004;

4. Tabera, J., Guinda, Á., Ruiz-Rodriguez, A., Señorans, F., Ibañez, E., Albi, T., Reglero, G., Journal of Agricultural and Food Chemistry, 52, 4774, 2004;

5. Cioffi, G., Pesca, M., Caprariis, P., Braca, A., Severino, L., Tommasi, N., Food Chemistry: 121, 105, 2010;

6. Gourine, N., Yousfi, M., Bombarda, I., Nadjemi, B., Stocker, P., Gaydou, E., Industrial Crops and Products, 31, 203, 2010;

7. Luís, Â., Domingues, F., Gil, C., Daurte, A.P., Journal of Medicinal Plants Research, 3, 886, 2009;

8. Andrade, D., Gil, C., Breitenfeld, L., Domingues, F., Duarte, A. P., Industrial Crops and Products, 30, 165, 2009;

9. Sultana, B., Anwar, F., Prybylski, R., Food Chemistry, 104, 1106, 2007;

10. Sreevidya, N., Mehrotra, S. , Journal of AOAC International, 86, 1124, 2003;

11. De Luca, V., Pierre, B., Trend in Plant Science, 5, 168, 2000;

12. Tawaha, K., Alali, F., Gharaibeh, M., Mohamed, M., El-Elimat, T., Food Chemistry, 104, 1372, 2007;

13. Pourmorad, F., Hosseinimehr, S., Shahabimajd, N., African Journal of Biotechnology, 5, 1142, 2006;

14. Scherer, R., Godoy, H., Food Chemistry, 112, 654, 2009.

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Síntese e estudo de materiais poliméricos baseados no polipirrol M. Magrinho, A.R. Santos, D. Mota, J. Matos, A. Faria

Unidade de Materiais Têxteis e Papeleiros - Universidade da Beira Interior

Abstract The polypyrrole is a relatively stable conducting polymer with an acceptable resistivity. These properties make it a good candidate for applications in different areas of technology, including technical textiles.

However, this material has a low mechanical strength, and therefore, its implementation requires a search for solutions. The polymer technology tells us that the properties of a material can be improved with the introduction of other polymers with the required characteristics.

Thus, this paper describes the electrochemical synthesis of polypyrrole, using as additive sodium dodecylbenzene sulphonate, polyethylene glycol and polyurethane.

We analyze the morphology, mechanical and electrical resistance of the obtained materials. The morphology of the materials was studied by scanning electron microscopy and optical microscopy, revealing the structure and the uniformity of the surfaces.

The values of resistivity in the order of 10-3 Ω.m, place these materials in the area of semiconductors. However, exhibit behavior similar to metal conductors, adapting itself perfectly to Ohm's Law.

The tensile tests with these materials showed a considerable mechanical strength. The rupture strength of these films reaches values around 200 MPa, a value close to the rupture tension of copper at 220 MPa.

1. Introdução Os polímeros condutores podem encontrar aplicações em diversas áreas de interesse, como são os têxteis técnicos [1] e a biomedicina[2]. Estas aplicações dos polímeros condutores exigem que os materiais, para além de condutores, sejam biocompatíveis, resistentes e processáveis.

Em geral, os polímeros condutores, são pouco resistentes e de difícil processamento mecânico. No entanto, o processo de síntese destes materiais permite a incorporação de outras substâncias com qualidades apropriadas à aplicação pretendida.

A biocompatibilidade é um factor decisivo na escolha dos materiais a estudar. De entre os polímeros disponíveis, o polipirrol é um bom candidato. É conhecido pela sua boa biocompatibilidade, estabilidade ambiental e simplicidade no processo de síntese, mesmo em meio aquoso.

Em química de polímeros, o melhoramento das propriedades de um polímero pode passar pela ligação do polímero a outros materiais com propriedades adequadas às necessidades do processo. A união do polipirrol com

outros materiais (Bhattacharya e Misra, 2004) pode ser conseguida por três métodos distintos: fusão, adesão e enxerto.

A fusão de polímeros pode ser aplicada ao polipirrol depois de obtido o polímero ou durante o próprio processo de síntese. Se o polipirrol se formar num meio que contenha outro polímero dissolvido, então o resultado será uma fusão de polímeros onde o polímero solúvel se encontra retido na matriz de polipirrol (Cakmak et al., 2005).

Deste modo, o polipirrol foi sintetizado pelo método electroquímico com o dodecilbenzenosulfonato de sódio como electrólito de suporte na presença de poliuretano e polietilenoglicol como polímeros de suporte.

2. Material e Métodos As sínteses das películas de polipirrol foram realizadas no potenciostato/galvanostato da Tacussel modelo PJT35-2. Como eléctrodos de trabalho e auxiliar foram utilizadas placas de aço inox com 2x5 cm2. Os eléctrodos foram polidos e lavados antes de cada utilização. Como referência utilizou-se o eléctrodo prata/cloreto de prata, referência 321 da Radiometer-Analytical.

Reuniu-se a célula de síntese em esquema de sandwich, figura 1, com uma distância de 8 mm entre eléctrodos, servindo o eléctrodo central como ânodo e os exteriores como cátodo. As sínteses decorreram sob um potencial de +600 mV relativamente ao eléctrodo de Ag/AgCl com um tempo de deposição de 24h.

Os filmes foram obtidos a partir de soluções com 1% de pirrol e 2,5% de dodecilbenzenosulfonato de sódio, tendo como variáveis as quantidades de poliuretano e polietilenoglicol 1500. O pirrol foi destilado antes da utilização e mantido em atmosfera de azoto, os restantes reagentes, com qualidade p.a., foram utilizados tal como fornecidos pela Sigma-Aldrich.

Figura 1 - Esquema da célula utilizada na obtenção dos copolímeros de polipirrol sobre inox

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Estudou-se a morfologia das peliculas por microscopia electrónica de varrimento num microscópio electrónico de varrimento Hitachi, modelo S2700, acoplado a um detector de raios X Oxford, modelo 60-74, operando a um potencial de 20 keV.

As espessuras dos filmes foram determinadas por microscopia óptica com microscópio metalográfico Leica MEF4M.

As medidas de Condutividade Eléctrica foram realizadas, aplicando uma diferença de potencial entre valores de ±1V com uma velocidade de varrimento de potencial de 50mV/s num Potencióstato PGZ 301 da Radiometer Analytical.

Os ensaios de tracção foram realizados num dinamómetro Adamel Lhomargy – Type Dy35 usando uma velocidade de distensão de 1mm/s. Foram usadas amostras com 30 mm de comprimento e 10 mm de largura.

3. Resultados e Discussão 3.1. Morfologia A introdução de polietilenoglicol ou poliuretano na solução de síntese permitiu a obtenção de materiais com diferentes características. Entre os materiais estudados, a película obtida com a adicção 2% de poliuretano na solução de síntese é a que apresenta uma melhor uniformidade de superfície e em profundidade.

A análise por microscopia eletrónica de varrimento, figura 2, mostra a superfície compacta da película de polipirrol. A imagem do corte transversal, obtido por microscopia ótica, da amostra com a melhor morfologia entre os materiais estudados, figura 3, confirma a uniformidade do material.

Figura 2 – Microscopia eletrónica de varrimento de uma amostra

de polipirrol obtida de uma solução com 2% de poliuretano.

Figura 3 – Corte transversal de uma amostra de polipirrol obtida de uma solução com 2% de poliuretano.

Entre os materiais estudados, a película obtida com a adicção 2% de poliuretano na solução de síntese é a que apresenta uma melhor uniformidade superficial e em profundidade.

A uniformidade do material permite uma maior continuidade entre as cadeias do polímero e consequentemente uma menor resistência elétrica e uma maior tensão rotura.

A quantidade e o tipo de aditivos utilizados na solução de síntese são determinantes para a uniformidade do material. O material obtido de uma solução com 1,25% de polietilenoglicol é um exemplo claro desta situação, as figuras 4 e 5 mostram-nos a superfície e o corte transversal desta película.

Figura 4 – Superfície de uma amostra de polipirrol obtida de uma solução com 1,25% de polietilenoglicol.

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Figura 5 – Corte transversal de uma amostra de polipirrol obtida de uma solução com 1,25% de polietilenoglicol.

A comparação entre as micrografias, com idêntica ampliação, figuras 2 e 4, e dos cortes transversais nas figuras 3 e 5 permitem-nos reafirmar a relevância das características dos aditivos nas propriedades das películas de polipirrol. 3.2. Estudos de resistividade Os filmes de polipirrol podem, segundo a sua composição e estrutura, apresentar tipos resistividade característicos dos semicondutores ou dos metais [3]. O estudo da resistividade elétrica nestes materiais mostrou uma relação linear entre a intensidade de corrente (I/A) na amostra e a diferença de potencial (U/V) aplicada nas suas extremidades. Este comportamento está de acordo com a lei de Ohm e é característico de materiais condutores como os metais.

Figura 6 – Determinação da resistividade num filme de polipirrol obtido de uma solução com 2% de polietilenoglicol

As resistividades observadas variam entre 7,4E-04 e os 8,0E-03Ω.m. Estes valores colocam os filmes de polipirrol mais próximos do semi-conductores que dos metais. No entanto, a relação corrente/potencial indica-nos um tipo condução eléctrica semelhante aos metais. Ou seja um “mar de electrões” que envolve todo o polímero e não uma condução do tipo “electrão-lacuna” característico dos semicondutores. De modo geral, pode-se afirmar que a introdução de copolímeros como o polietilenoglicol e o poliuretano melhoram as qualidades elétricas dos filmes de polipirrol. As figuras 7 e 9 indicam uma tendência clara para a variação da resistividade destes materiais com o aumento da quantidade do aditivo .

Figura 7 – variação da resistividade em filmes de polipirrol obtidos de soluções com diferentes concentrações de polietilenoglicol.

Figura 8 – variação da resistividade em filmes de polipirrol obtidos de soluções com diferentes concentrações de poliuretano.

3.3. Resistência mecânica A fraca resistência mecânica do polipirrol não lhe permite uma utilização a nível industrial. Para que o polipirrol possa ser largamente utilizado em aplicações industriais, as suas propriedades mecânicas tais como: flexibilidade, elasticidade e resistência à tração, têm que ser melhoradas.

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Em química de polímeros, o melhoramento das propriedades de um polímero pode passar pela ligação do polímero a outros materiais com propriedades adequadas às necessidades do processo. Este objetivo pode ser alcançado através da fusão de polímeros (Bhattacharya e Misra, 2004). A fusão do polipirrol com o poliuretano e o polietilenoglicol permitiu alcançar tensões de rotura significativas para estes materiais.

Figura 9 – variação da tensão de rotura em filmes de polipirrol obtidos de soluções com diferentes concentrações de polietilenoglico.

Figura 10 – variação da tensão de rotura em filmes de polipirrol obtidos de soluções com diferentes concentrações de poliuretano.

A tendência da variação da tensão de rotura com o aumento da quantidade do copolímero na solução de síntese é clara e permite-nos antecipar novas melhorias nesta propriedade. Mais, os valores obtidos para a tensão de rotura destes materiais aproximam-se dos valores de tensão de rotura de outros polímeros conhecidos, como é o caso do polietileno de alta densidade com 37 MPa. 4. Conclusões A introdução de polímeros solúveis na solução de síntese do polipirrol permite melhorar as qualidades destes materiais. As propriedades elétricas e mecânicas dos materiais obtidos por fusão do polipirrol com outros polímeros melhoram com a introdução de polímeros que contribuem para coplanaridade dos sistemas conjugados do polipirrol e consequente redução da resistividade elétrica. Referências 1. Foitzik R.C., Kaynaka A,, Pfeffer, F.M., Synthetic Metals,157,534-539, 2007 2. Wuang S.C., Neoh K.G., Kang E.T., Pack D.W. , Leckband D.E., Journal Of Materials Chemistry, 17 , 3354-3362, 2007 3. Chandra S., Annapoorni S., Singh F., Sonkawade R.G., Rana J.M.S., Ramola R.C., Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions With Materials and ATOMS, 268, 62-66, 2010.

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Electrochemical degradation of 8-aminonaphthalene-2-sulfonic acid: a comparative study between Si/BDD and

Ti/Pt/PbO2 anodes

A.S.Rodrigues, M.J. Pacheco, L. Ciríaco, A. Lopes UMTP and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal

Abstract

The anodic oxidation of aqueous solutions containing 200 mg L-1 of 8-aminonaphthalene-2-sulfonic acid has been investigated using a batch stirred cell, operating under galvanostatic conditions at a current density of 30 mA cm-

2. The performance of two different anodes, boron-doped diamond (BDD) and Ti/Pt/PbO2, were compared under the same experimental conditions in two different supporting electrolytes, NaCl and Na2SO4. Degradation assays were followed by Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) determinations and UV-Vis spectrophotometric analysis. It was found that the electrocatalytic activity of both anodes depends on the supporting electrolyte. It should be noted that in the presence of chloride, COD and TOC removals occur mainly in the first hour of the assay, while the removal with sulfates occurs throughout the assay. However, mineralization was always much higher in the presence of sulfates. The performance of the Si/BDD electrode was better than that of the Ti/Pt/ PbO2 electrode. Introduction

Sulfonated naphtalenic amines are very toxic pollutants released to the environment in the effluents of several industries. One of the main sources of this class of compounds, which have been highly referred in the literature, is the azo dyes reduction products. In fact, many azo dyes, used in the textile industry, are substituted with the sulfonic acid group and during its biological degradation many different sulfonated naphtalenic amines can be formed. Some of these organics are biorefractory, which prevent effective biological pollutant abatement [1]. So, electrochemical processes, such as anodic oxidation, can be used as alternative/complement to biological treatments. In fact, the anodic oxidation method promises versatility, environmental compatibility and potential cost effectiveness for the degradation of different organic pollutants [2,3]. The main purpose of the electrochemical wastewater treatment is the complete oxidation of organics to CO2 or their conversion to biodegradable compounds. Many studies have been carried out on electrochemical treatment of organic compounds and several anode materials have been tested [3]. However the best results were obtained using high oxygen overpotential anodes, such as boron doped diamond (BDD) and PbO2 [4,5]. Both anodes have high oxidation power and are able to generate highly reactive physisorbed hydroxyl radicals. For this kind of electrodes, very high current efficiencies may be obtained, and complete mineralization of the organic compounds can be achieved [3,4].

In the present work, the anodic oxidation of 8-aminonaphthalene-2-sulfonic acid (see chemical structure in Fig.1) in aqueous solutions was investigated. The performance of two different anodes Si/BDD and Ti/Pt/PbO2 were compared in two different supporting electrolytes, NaCl and Na2SO4.

HO3S

NH2

Figure 1. Molecular structure of 8-aminonaftalene-2-sulfonic

acid.

Materials and Methods

The amine studied in this work was 8-aminonaphthalene-2-sulfonic (8AN2S), purchased from Sigma Aldrich (96%) and used without further purification. Sodium chloride (Panreac, 99.5%) and sodium sulfate (Merck, 99.5%) were used as supporting electrolyte in a concentration of 5 g L-1. Ti/Pt/PbO2 electrode was prepared by thermal electrochemical method. The Si/BDD electrode was purchased from Adamant Technologies/CSEM. Electrolyses were performed in a batch stirred cell, operating under galvanostatic conditions, at a current density of 30 mA cm-2. Si/BDD and Ti/Pt/PbO2 were used as anode, both with a geometric area of 10 cm2, and a stainless steel plate, with identical area, was used as cathode. Assays were run for 6 h, using 200 mL of a solution containing an amine concentration of 200 mg L-1. Treatment efficiency was evaluated by UV-Vis absorption spectrophotometry, using a Shimadzu UV-1800 spectrophotometer, by Chemical Oxygen Demand (COD) determinations, using the closed reflux dichromate, titrimetric method [6], and by Total Organic Carbon (TOC) determinations, performed in a Shimadzu TOC-VCPH apparatus.

Results and Discussion

Ultraviolet-Visible spectrofotometry analysis

The oxidation of 8AN2S at Si/BDD and Ti/Pt/PbO2 electrodes was monitored by spectrophotometric measurements, which, in the UV region, allow a straightforward way to follow the elimination of aromatic compounds from aqueous solutions. Figure 2 and 3 show the changes in the UV spectra obtained during the 8AN2S degradation assays using,

121

respectively, the Si/BDD and Ti/Pt/PbO2 anodes in the presence of either sulfate or chloride ions. The spectra show three main bands which are characteristic of the naphthalenic amines, occurring around 210, 250 and 340 nm. The UV spectra analysis allowed to confirm that 8AN2S was always more quickly eliminated at Si/BDD than at Ti/Pt/PbO2. In the spectra obtained for the degradations performed, in the presence of sulfate ions, with Si/BDD, the intensity of all bands decreases continuously. This fact seems to indicate that, in the first 4 h of the assay, the naphatalenic ring is gradually oxidized and opens. However, some 8AN2S molecules seem to remain in the solution up to the end, thus pointing to a mechanism of electrochemical combustion rather then conversion. In the case of chloride, there is a sharp decrease during the first hour, in opposition of what happens with sulfates. The 8AN2S molecule almost disappears as can be seen by the vanishing of the naphtalenic amine characteristic spectra profile. Additionally, in this supporting electrolyte the appearance of a new band at 290 nm is observed, which is attributed to the presence of hypochlorite ion in the solution. This band also appears in the spectra during the electrodegradation with Ti/Pt/PbO2 (Figure 3b) and its intensity increases after the first hour. With this anode, after the assay’ first hour, the amine’s characteristic spectra profile disappears and the spectra remains almost unchanged until the end. In the presence of sulfates (Figure 3a), the bands intensity decrease and, after 4 hours, they completely change their profile. This observation may suggest that the intermediates formed may polymerize and precipitate, remaining in the solution some suspended solids.

Figure 2. UV spectra of the samples collected during the 8AN2S electrolysis assays’ performed with Si/BDD and using (a) Na2SO4 and (b) NaCl as supporting electrolyte.

Figure 3. UV spectra of the samples collected during the 8AN2S electrolysis assays’ performed with Ti/Pt/PbO2 and using (a) Na2SO4 and (b) NaCl as supporting electrolyte.

COD and TOC analysis

In general, for both anodes, the removal of COD is more pronounced than that of TOC (Figure 4 and 5). However, for the tests run with sulfate, in the first hour the decays of COD and TOC are similar, thus suggesting that, in this electrolyte, the initial phase of oxidation is largely due to the mineralization of the amines. The analysis of data obtained with chlorides suggest that more than 50% of COD and TOC total removals occurs in the two first hours of electrolysis, while, with sulfates, removal occurs gradually throughout the test. These results are consistent with the analysis of the spectra of UV-Visible previously discussed. Figure 4. Influence of supporting electrolytes on the change of normalized COD and TOC values during 8AN2S degradation assays with the Si/BBDD anode. .

Figure 5. Influence of supporting electrolytes on the change of normalized COD and TOC values during 8AN2S degradation assays with the Ti/Pt/PbO2 anode. . The performance of Si/BDD anode is always better than that of Ti/Pt/PbO2 for the same operating conditions. After 6 h of treatment on Si/BDD anode, in the presence of sulfates, COD and TOC removals were, respectively, 97% and 91% while under the same conditions the Ti/Pt/PbO2 anode only achieved 58% and 33%. The large difference in COD and TOC removals can be explained by the different nature of OH generated on both anodes. Although physisorbed radicals are formed in both anodes, BDD( OH) is more weakly adsorbed than PbO2( OH), thus being more reactive towards organics oxidation [5]. For the Ti/Pt/PbO2, the best COD removal was 83% obtained in the presence of chloride while in the presence of sulfate it was only achieved 58%. Moreover, the TOC removals were very low; the best result achieved was 33% in the presence of sulfates.

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Conclusions

The anodic oxidation treatment of simulated wastewater containing 8-aminonaphthalene-2-sulfonic acid has been investigated using two different electrode materials, Si/BDD and Ti/Pt/PbO2. The results of electrolysis performed with two different electrolytes have shown the following:

The electrochemical degradation of this organic compound was not only significantly affected by the anode material but also by the nature of the supporting electrolyte. The mineralization in the presence of NaCl is much slower than the oxidation degree of the amine. It is clear the formation and accumulation of intermediates that resist to further oxidation.

Using the Si/BDD anode, the best COD and TOC removals, higher than 90%, were obtained with Na2SO4 as supporting electrolyte.

Using the Ti/Pt/PbO2 anode, the COD removal rate increases in the presence of NaCl due to the chlorine active species electrogenerate which promote the oxidation in the bulk solution.

A comparison of the results obtained with both electrode materials, in the presence of either sulfate or chloride, showed that a faster 8AN2S oxidation/mineralization was achieved using the Si/BDD anode.

References

1. Pinheiro, H. M., Touraud, E., and Thomas, O., Dyes and Pigments, 61, 121, 2004.

2. M. Panizza, G. Cerisola, Direct and mediated anodic oxidation of organic pollutants, Chem. Rev. 109 (2009) 6541-69.

3. Santos, V., Diogo, J., Pacheco, M.J., Ciriaco, L., Lopes, A. (2010). Chemosphere 79, 637-645.

4. Pacheco, M.J., Santos, V., Ciriaco, M.L., Lopes, A. J. Haz. Mater. (In Press).

5. Flox, C., Arias, C., Brillas, E., Savall, A., Groenen-Serrano, K. (2009). Chemosphere 74, 1340-1347.

6. Eaton, A., Clesceri, L., Greenberg, A., Standard Methods for Examination of Water and Wastewater. APHA, AWWA, WEF, 21st Ed., Washington, 2005.

Acknowledgements

The financial support of Fundação para a Ciência e a Tecnologia, FCT, BII-12/UMTP/UBI/2009.

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Extraction, purification and structural characterization of phenolic compounds from Prunus avium

S. Santos, M.I. Ismael, J.A. Figueiredo, R. Simões, J. Rodilla, A.P. Duarte UMTP and Department of Chemistry, University of Beira Interior, Covilhã, Portugal

Abstract The aim of this work was the study of the proprieties of phenolic compounds, constituents of the cherry tree (Prunus avium), after isolation and characterization of these components. Preparation of extracts of the wood of cherry tree was made with a Soxhlet extractor, with acetone and ethyl acetate, and the compounds were isolated and purified by column chromatography. Pure compounds were characterized and identified by spectroscopy using infrared (IR) spectroscopy and nuclear magnetic resonance spectroscopy of proton (1H-NMR) and carbon (13C-NMR), confirming the existence of phenolic compounds in the extracts. The structures identified were then compared to those already described in literature. Introduction Wood is one of the main materials used by humanity featuring multiple applications, and raw material for multiple products. In particular, the wood of cherry tree has several important features, being this wood is very tough, strong, flexible and elastic, with ability for use in furniture, musical instruments, doors, windows, sculptures, woodwork, between others. This wood has a high economic importance, because it introduces features and possesses several biological compounds with interest. Cherries (Prunus avium) are important commercially as a table fruit [1]. In Portugal, the cultivation of cherries is concentrated in the northeast of the country, in a region called “Beira Interior” [2]. The consumption of cherries reduce the risk of cancer, pain from arthritis and inflammation, symptoms of exercise-induced muscle damage, oxidative stress in older people, and offer protection against neurodegenerative diseases. The beneficial effects of cherries may be attributed to the presence of phenolic compounds that exert potent antioxidant capacity [2, 3]. Flavonoids are a group of phenolic compounds diverse in chemical structure and characteristics. Widely distributed in the leaves, seeds, wood, bark and flowers of plants, and to date, more than 6000 flavonoids have been identified. In plants, these compounds afford protection against ultraviolet radiation, pathogens, and herbivores [4]. The monomeric unit for these compounds consists of two substituted benzene rings A and B joined, in most cases, by a heterocyclic ring C, as shown in figure 1 [5]. There is an array of different substitution patterns on A, B, and C rings, as well as differences in where the B rings is bonded to the C ring, providing possibility for the existence of numerous flavonoids, differing in their biological characteristics and chemical structures. The flavonoids are divided into several classes, which are chalcones, dihydrochalcones, aurones, flavonols,

flavanols (catechins), flavan-3,4,-diols, flavones, flavanones, anthocyanidins, isoflavones, isoflavanols, and isoflavanones [4, 5]. Within this context, the objective of this work was the extraction the phenolic compounds of the wood of cherry tree and the isolation and purification these several products, which can be used as antioxidant compounds.

O

2'3'

4'

5'

6'

345

6

7

8

A C

B

1'

1

2

Figure 1 - The generic structure of flavonoids. Materials and Methods Cherry wood was collected in the area of Fundão. After collected, samples were dried at room temperature and then in an oven at 40 ºC. Later, it was ground in a mill (20 mesh), and then was available for extraction. The samples were submitted to extraction processes with acetone and ethyl acetate (EtOAc) in a Soxhlet extractor, during 24 hours. Purification of the compounds was made by column chromatography, using silica gel 230-400 mesh ASTM in the stationary phase and the mobile phase was used gradient elution ethyl acetate:cyclohexane and methanol to wash the columns. Fractions obtained were analyzed by thin layer chromatography, performed on silica gel plates from Merck with 0,2mm thickness, 60 F245, in aluminum support and concentrated in rotary evaporator. Structural characterization was undertaken by infrared (IR) spectroscopy, nuclear magnetic resonance spectroscopy of proton (1H-NMR) and carbon (13C-NMR) performed on BRUKER AC 250 spectrometer, operating at 250 MHz for proton and 62.90 MHz for carbon. Chemical shifts are reported in units of δ (ppm) and were obtained for each compound, at room temperature and in solution of deuterated acetone. Coupling constants (J) are expressed in Hz. Results and Discussion Ethyl acetate extract of the wood of cherry tree (1.0g) was subjected to silica gel column chromatography with gradient elution EtOAc: Cyclohexane. Were obtained four pure compounds, 1 (0.040g), 2 (0.040g), 3 (0.070g) and 4 (0.119g). Acetone extract of the wood of cherry tree (1.0g) was purified by column chromatography with gradient elution EtOAc: Cyclohexane. Six pure compounds were obtained: 5 (0.015g), 6 (0.011g), 7 (0.006g), 8 (0.061g), 9 (0.006g) and 10 (0.016g).

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Some pure compounds were structurally characterized by 1H-NMR and 13C-NMR (table 1). The proposed structures for compounds isolated from extracts of cherry, defined as 1, 2, 4, 5 and 8 were compared with the structures proposed by our working group [6], concluding that structures have very similar spectroscopic data to those obtained in this study, except the compound 2 which represents another structure (figure 2).

Conclusions In this study were isolated and purified compounds from Prunus avium and was observed a large quantity and diversity of phenolic compounds in this extracts. By column chromatography was possible to obtain the pure phenolic compounds. Were identified 5 compounds that occur also in other species, which have the following names: Naringenin 1, Dihydrokaempferol 2, Catechin 4, Pinostrobin 5 and Pinocembrin 8, whose structures are in figure 2.

Table 1 – Chemical shifts (δ in ppm) of signals from 1H-NMR and 13C-NMR in C3D6O, for compounds 1, 2, 4, 5 and 8.

Naringenin

1 Dihydrokaempferol

2 Catechin

4

Pinostrobin 5

Pinocembrin 8

Position

δ 1H (ppm), m, J (Hz)

δ 13C (ppm)


δ 13C (ppm)


δ 13C (ppm)


δ 13C (ppm)


δ 13C (ppm)

2 5.44, dd, 12.90, 3.00

79.90 4.71, m 84.42 4.55, d, 7.72 (3ax)

81.73 5.42, dd, 13.00, 3.10

79.18 5.40, dd, 12.80, 3.20

80.44

3 3.19, dd, 17.10, 12.00

43.44 3.12, s 73.18 4.01, m 67.38 2.83, dd, 17.20, 3.10

43.35 2.72, dd, 17.20, 3.20

44.19

4ax ˇ ˇ ˇ ˇ 2.52, dd, 16.10

ˇ ˇ ˇ ˇ ˇ

4eq ˇ 197.19 ˇ 198.35 2.91, dd 28.36 ˇ 195.69 ˇ 197.31 5 12.19, s 165.24 11.73, s 165.06 ˇ 156.25 12.05, s 167.96 ˇ 168.40 6 5.96, d, 1.20 96.70 6.01, d, 2.10 97.16 6.02, d,

2.16 (8) 95.13 6.08, d,

2.30 95.12 5.88, d, 2.20 97.21

7 ˇ 167.30 ˇ 167.91 ˇ 156.75 ˇ 164.13 ˇ 165.48 8 5.96, d, 1.20 95.79 5.97, d, 2.10 96.11

5.87, d 94.42 6.07, d,

2.30 94.23 5.91, d, 2.20 96.26

9 ˇ 164.34 ˇ 164.25 ˇ 155.93 ˇ 162.75 ˇ 164.66 10 ˇ 103.16 ˇ 101.59 ˇ 99. 64 ˇ 103.12 ˇ 103.40 1’ ˇ 130.72 ˇ 129.17 ˇ 131.15 ˇ 138.35 ˇ 140.41 2’ 7.38, d, 8.10 129.00 7.44, d, 8.40 130.38 6.89, d,

1.50 114.73

3’ 6.90, d, 8.10 115.86 6.92, d, 8.40 115.98 ˇ 144.73 4’ ˇ 158.64 ˇ 164.25 ˇ 144.66 5’ 6.90, d, 8.10 116.12 6.92, d, 8.40 115.98 6.80-6.74,

m 114.73

6’ 7.38, d, 8.10 129.00 7.44, d, 8.40 130.38 6.80-6.74, m

119.11

7.45-7.26,

m

128.82 126.08

7.47-7.34, m

129.78 129.72 129.65 127.36

OCH3-7 ˇ ˇ ˇ ˇ ˇ ˇ 3.81, s 55.63 ˇ ˇ s: singlet; d: doublet; dd: double doublets; m: multiplet

References 1. Gómez, D.G.; Lozano, M.; León, M.F.F.; Bernalte,

M.J.; Ayuso, M.C.; Rodríguez, A.B.; Journal of Food Composition and Analyses 23:533-539, 2010.

2. Serra, A.T.; Seabra, I.J.; Braga, M.E.M.; Bronze, M.R.; Sousa, H.C.; Duarte, C.M.M.; J. of Supercritical Fluids 55:184-191, 2010.

3. Faniadis, D.; Drogoudi, P.D.; Vasilakakis, M.; Scientia Horticulturae 125:301-304, 2010.

4. Erlund, I.; Nutrition Research 24: 851-874, 2004. 5. Cook, N.C.; Samman, S.; Nutritional Biochemistry 7:

66-76, 1996. 6. Lopes, P.; Graduation thesis, University of Beira

Interior, Covilhã, 2006.

Figure 2 – Phenolic compounds isolated in this study.

OOH

OH

OH

OH

OH

OR4

OH O

R3

R1

R2

1: R1=H, R2=OH, R3=H, R4=OH2: R1=H, R2=OH, R3=OH, R4=OH5: R1=H, R2=H, R3=H, R4=OCH38: R1=H, R2=H, R3=H, R4=OH

4

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