Дисертації з теми "Sustainable biopolymers"

The development of biodegradable plastics from sustainable sources is at the forefront of chemical research. One such example is the production of polylactide (PLA) via the ring-opening polymerisation (ROP) of the cyclic ester lactide (LA). Current industrial metal initiators utilised for the ROP of LA do not allow control over the stereochemistry of the resulting product. This thesis will investigate various initiators containing a variety of ligand sets for the ROP of rac-LA. Chapter 1 introduces the ROP of rac-LA, the mechanisms utilised and the methods employed for characterisation of PLA. A review of the current literature of recent developments in the production of PLA via various metal initiators is also included. Chapter 2 reports the development of a series of group (IV) complexes containing various amine tris(phenolate) ligands, where the sterics and electronics have been varied. Such complexes were trialled for the ROP of rac-LA as well as the ROP of trimethylene carbonate (TMC). The ability of such initiators to produce copolymers of rac-LA/TMC and rac-LA/isosorbide was also investigated and discussed. Chapter 3 describes the synthesis of a range of group (IV) complexes containing Salalen ligands. The sterics of the ligands have been varied and the ability of the initiators to initiate the ROP of rac-LA in a stereocontrolled fashion has been investigated. Furthermore, the complexes have been trialled for the degradation of PLA into methyl lactate, an important starting material in the production of LA. Chapter 4 investigates the development of Al(III) Salalen complexes for the ROP of rac-LA, where the sterics and electronics of the ligand have been varied. Kinetic investigations have been carried out to aid the understanding of the polymerisation process. Chapter 5 provides details of the reaction procedures for the synthesis of ligands, complexes and polymers. Kinetic procedures are also reported together with details of the analytical techniques employed.

Content: A novel class of bio-based polymers have been developed within the LIFE BIOPOL European project aiming to replace traditional re-tanning and fat-liquoring products reducing environmental impacts and increasing the safety of leather. The purpose of the project is to enhance the recovery and reuse of different bio-derived by-products from leather and agro-industrial sector to produce eco-friendly and renewable bio-polymers with high re-tanning and fat-liquoring characteristics. The LIFE BIOPOL project aims to make bio-based polymers in order to reduce the following parameters in re-tanning phase: - 20-30% COD, - 50-60% of inorganic salts (Sulphates and Chlorides), - 90% of Cr (III) salts, - 20% of water used in the leather process. Other important goals of the project are: - reduction 70-90% of hazardous and environmental polluting substances normally found in conventional chemicals, - reactivity enhancement of 30-40% of the new biopolymers compared to the current leather - application technology, - reduction of 70-80% of the Product Environmental Footprint of the new biopolymers related to the state of the art. The vegetal biomasses and the tanned hides by-products were pretreated in order to obtain suitable building blocks for the production of bio-based polymers. Several protocols involving polymerization were used in order to achieve the synthesis of the biopolymers, which have been carried out at lab scale. Macromolecular characterization of the biopolymers was performed in order to rationalize the synthetic strategy and practical application of the products giving important parameters such as molecular weight and chemical composition of the new biopolymers. Performances of new bio-based polymers have been inspected and compared with traditional chemicals through application on different types of leather. The benefits of the new products within leather making process were evaluated through chemical analyses of re-tanning and fat-liquoring effluents. The upgrade of the developed chemistry will be performed within a new devised prototype plant specifically designed and built-up for producing the bio-based polymers at industrial scale Take-Away: Production of leather making biopolymers from biomasses and industrial by-products through Life Cycle Designed Processes

Development and characterization of biopolymers was done in AIJU’s laboratories. AIJU, Technological Institute for children’s products and leisure is based in Spain. The work has the aim to study qualities and characteristics of bioplastics’ blends, in order to design where improvements can be executed. Biopolymers represent a sector with great development possibilities because they combine high technical potential and eco-sustainability. Nowadays, plastic pollution has becoming increasingly concerning, particularly in terms of management of waste. Bioplastics provide an alternative for the disposal of products, reducing the volume of waste and enhancing the end of life recovery. Despite the growing interest in biopolymers there is some gaps that need be filled. The main objective on this work, is the optimization of bioplastics mechanical properties, to find suitable substitutes, as similar as possible to conventional plastics. Firstly, investigations on processability of biomaterials has been deepen since the project deals with toy manufacturing’s sector. Thus, starting from laboratory scale the work aspires to expand industrially. By working with traditional machines, it was notable that, with some limited modifications, the equipment can perform the same functions. Therefore, operational processes do not emerge as an obstacle to the production chain. Secondly, after processing bio-blends, they are characterized by thermal tests (melt flow index, differential scanning calorimetry-DSC, thermogravimetry-TGA) and mechanical tests (traction and flexural tests, Charpy impact, SHORE D hardness and density). While the compatibility does not show relevant results, mechanical improvements has been visualized with addition of more ductile materials. The study was developed by inclusion of sustainable additive VINNEX® to blends. The thesis has highlighted that integration of more flexible materials provides elasticity without compromising bioplastics’ properties.

This thesis reports on the research undertaken to investigate the reduction of the environmental impacts of plastic packaging through the effective selection and application of biopolymers during the pack design process. The principle objective of this research is to develop an understanding of the strengths and weaknesses of biopolymers as a packaging material and to develop a framework which enables biopolymers to be considered at each stage of the pack design process to enable their effective and appropriate selection and use.

This work has been conducted in order to determine the solubility and diffusion coefficients of different aromatic substances in two different grades of polylactic acid (PLA), Amorphous (PDLLA) and Crystalline (PLLA); in particular the focus is on the following terpenes: Linalool, α-Pinene, β-Citronellol and L-Linalool. Moreover, further analyses have been carried out with the aim to verify if the use of neat crystalline PLA, (PLLA), a chiral substrate, may lead to an enantioenrichment of absorbed species in order to use it as membrane in enantioselective processes. The other possible applications of PLA, which has aroused interest in carry out the above-mentioned work, concerns its use in food packaging. Therefore, it is interesting and also very important, to evaluate the barrier properties of PLA, focusing in particular on the transport and absorption of terpenes, by the packaging and, hence, by the PLA. PLA films/slabs of one-millimeter thickness and with square shape, were prepared through the Injection Molding process. On the resulting PLA films heat pretreatment processes of normalizing were then performed to enhance the properties of the material. In order to evaluate solubility and diffusion coefficient of the different penetrating species, the absorption kinetics of various terpenes, in the two different types of PLA, were determined by gravimetric methods. Subsequently, the absorbed liquid was extracted with methanol (MeOH), non- solvent for PLA, and the extract analyzed by the use of High Performance Liquid Chromatography (HPLC), in order to evaluate its possible enantiomeric excess. Moreover, PLA films used were subjected to differential scanning calorimetry (DSC) which allowed to measure the glass transition temperature (Tg) and to determine the degree of crystallinity of the polymer (Xc).

La cellulose, un biopolymère renouvelable, peut remplacer les matériaux non biodégradables dans les applications industrielles. Elle est d'abord dissoute, puis transformée (par exemple en fibres) et enfin « régénérée » (recristallisation par ajout d'eau). Cependant, la dissolution de la structure cristalline très stable nécessite des solvants agressifs et polluants, au contraire des liquides ioniques (IL). Cette thèse étudie le processus de dissolution et l'état dissous pour deux liquides ioniques sélectionnés comme solvants efficaces. Nous étudions la structure et la conformation des chaînes de cellulose par la diffusion des rayons X et des neutrons. Les signaux sont très faibles (< 1 cm⁻¹), en raison de la forme fine des bâtonnets, du faible contraste et de la difficulté à mesurer en raison de la grande sensibilité à l'eau. Le chapitre 1 résume l'état de l'art sur les solutions dans des solvants industriels et dans les liquides ioniques, et sur les études de diffusion, de la lumière, des rayons X et des neutrons, montrant des situations diverses. Le chapitre 2 présente la préparation des échantillons et les techniques. Le chapitre 3 présente des études de Diffusion des rayons X aux Petits Angles (DXPA), réalisées à l'aide de spectromètres sur synchrotron, à flux élevé et à faisceau étroit. Nous avons d'abord étudié la cellulose microcristalline (MCC, degré de polymérisation DP = 200 unités) dans deux IL à base de butyl-méthyl-imidazolium : acétate (BmimAc) ou chlorure (BmimCl). Différents régimes sont attendus à partir d'études rhéologiques. - Dans le régime dilué (0,005 - 0,02 g/g). La diffusion est ajustée au facteur de forme P(q) d'une chaîne en forme de bâtonnet, entourée d'une coquille de densité différente de celle du solvant, avec éventuellement une grande longueur de persistance (> 7 nm). - Pour des concentrations plus importantes, dans des cas encore bien dissous, un facteur de structure révèle des répulsions inter-chaînes faibles, sans alignement fort. - A des concentrations plus élevées, la diffusion suggère une séparation de phase liquide-liquide. - Enfin, aux concentrations les plus élevées, des cristaux non dissous sont détectés à grand q (WAXS), un grand avantage de notre technique. La coexistence avec les cristaux a été étudiée pendant le gonflement de films ou de fibres de cristaux de nanocellulose, par balayage en faisceau étroit d'un gradient de concentration. L'effet d'un faible pourcentage d'eau ajoutée a été testé, les Il bons solvants étant assez hygroscopiques. Au-delà de quelques pour cent d'eau, une diffusion beaucoup plus forte suggère de fortes fluctuations de concentration, ou une structure biphasique, utile pour comprendre les premières étapes de la « régénération » (recristallisation) par ajout d'eau. Les courbes de diffusion de cellulose d'autre origine et de poids moléculaire également faible (rayonne, nanocristaux - CNC) sont similaires à celles du MCC. Celle de la cellulose bactérienne montre aussi une identité complète à l'échelle locale, mais avec des agrégats indépendants visibles aux moyens q. Le chapitre 4 présente les mesures : - de Diffusion des Neutrons aux Petits Angles (DNPA) aux faibles concentrations, le profil de DNPA est celui de la DXPA, ce qui permet une évaluation complémentaire des densités de longueur de diffusion. Par extrapolation à la fraction zéro de cellulose deutérée, nous avons tenté d'extraire la fonction intra-chaîne S₁(q)~P(q), et la fonction inter-chaîne S₂(q). Des difficultés sont apparues à faible q en raison de la forte remontée de la cellulose deutériée bactérienne. A q élevé il y a accord avec la DXPA. - de Diffusion de Neutrons aux Grands Angles (DNGA) suit les corrélations à courte échelle. Nous avons effectué différentes deutériations : soit le cation Bmim, soit l'anion Ac, soit les deux. Par comparaison nous discutons de l'absorption possible des anions acétate sur les chaînes
Cellulose, a renewable bio-polymer, can replace non-biodegradable materials in various technological applications. Industrially, it is first dissolved, then processed (e.g. by spinning), and finally “regenerated” (recrystallization by adding water). However, dissolution from the very stable crystal structure requires harsh, pollutant solvents for individual chains to stay in solution. Ionic liquids (ILs) have emerged as non - polluting effective solvents. This thesis aims at the dissolution process and dissolved state checking how the two selected ILs are successful solvents, which is controversial. Our approach is to study structure and conformation of cellulose chains by X-Ray and neutron scattering, which are very weak (< 1 cm⁻¹), due to the small volume of the thin rod, the low contrast and difficult to measure due to high sensitivity to water. Chapter 1 summarizes the state of the art on solutions of cellulose in different widely industrially used solvents, in ionic liquids, and in scattering studies, light, X-rays and neutrons, showing various states of dispersion. Chapter 2 presents the preparation of the samples and the techniques. Chapter 3 reports Small Angle X rays Scattering (SAXS) studies, using high flux and narrow beam synchrotron spectrometers. We first monitored MicroCrystalline Cellulose (MCC, Degree of Polymerisation DP ≈ 200 units) in two Butyl-methyl-imidazolium based ILs: acetate (BmimAc), or Chloride (BmimCl). Different regimes are assumed from rheological studies. -In the dilute regime (0.005 – 0.02 g/g). Scattering is fitted to the form factor P(q) of a rod-like chain, surrounded by a shell of density different from the one of the solvent, with possibly a large persistence length (> 7 nm). -For larger concentrations, in yet well dissolved cases, a structure factor unveils soft interchain repulsions, without strong alignment. -At higher concentration, the scattering suggests a liquid-liquid phase separation -Finally, at the highest concentrations, non-dissolved crystals are detected at large q (WAXS), a great advantage of our technique. The coexistence with crystals was also investigated during swelling in nanocellulose crystals films or fibers, through narrow beam scanning of a concentration gradient. The effect of a small percentage of added water was tested, the IL good solvents for cellulose being quite hygroscopic. Above a few per cent of water, much stronger scattering suggests strong concentration fluctuations, or biphasic structure, useful to understand the first stages of the “regeneration” (recrystallization) step performed by adding water, to obtain the final products. Cellulose of other origin and similarly small molecular weights (in rayon, and CNC), superimpose their scattering on the one of MCC. Bacterial cellulose scattering superposes only at large q (hence a complete identity at local scale), but shows an additional strong low q upturn, due to independent aggregates. This opens the way to neutron scattering experiments using deuteriated cellulose, which is available only in a bacterial form. Chapter 4 reports the measurements of: -Small Angle Neutron Scattering (SANS) shows for low concentrations a profile similar to SAXS, allowing a complementary evaluation of the Scattering Length Density of cellulose. Using extrapolation at Zero Deuteriated Cellulose Fraction, we attempted the extraction of the intrachain function S₁(q)~P(q), the interchain function S₂(q). Difficulties appeared at low q due to the strong upturn, while high q showed agreement with the SAXS measurement of the form factor below c*. -Wide Angle Neutron Scattering (WANS) was used to track the correlations at short scale. Different solvents were used in which either the Bmim cation, or the anion Ac, or both, were deuteriated using our own synthesis processes. Comparisons enable us to discuss about possible absorption of the acetate anions on the cellulose chains

Tese de Mestrado em Design de Moda
A moda é um mecanismo veloz, efémero e sôfrego de novi¬dade. Ao longo da história da moda e do design, os têxteis têm sido intimamente relacionados com a inovação a nível científico e industrial. Actualmente, as novas exigências sociais e a evolução tec¬nológica permitem a concepção de ideias e materiais nunca antes imaginados. Alega-se que o vestuário se está a transformar na expressão de um estilo de vida consciencioso e de uma personalida¬de onde coexistem preocupações com o ambiente e com a individualidade, e a realização de desejos e necessidades humanas. Deste modo, é crucial a investigação de soluções para novas bases têxteis que correspondam às exigências de sustentabilidade, funcionalidade e estética, quer do consumi¬dor quer do designer de moda. Em conformidade, este trabalho de investigação foca a análise de algumas fibras têxteis naturais e manufactura¬das, sob o ponto de vista das suas propriedades, aplicações e processamento, procurando esclarecer e desmitificar o carácter ecológico de ambas. Em consonância, é feita a aná¬lise comparativa do processamento do algodão e do lyocel, permitindo observar a existência de novas fibras manufactu¬radas que se apresentam como uma alternativa sustentável para a produção de novas bases têxteis para produtos de moda. Desta forma, a presente dissertação pretende realçar o carácter sustentável de novas bases têxteis, desmitifican¬do o carácter ecológico de algumas fibras naturais, como o algodão, face à carga poluente que advém do seu processo de tranformação.
ABSTRACT - Fashion is fast, ephemerous and longs for innovation. Throu¬ghout the history of both fashion and design, textiles have been intimately connected with scientific and industrial inno¬vation. Nowadays, new social demands and technological evolu¬tion have allowed a conception of ideas and materials never imagined before. It is alleged that clothing is becoming the voice of a conscien¬tious lifestyle and of a personality where environmental and individuality concerns, human needs and the fulfillment of desires all coexist. As such, it is crucial to explore new textile structures so¬lutions that correspond to the demands for sustainability, functionality and aesthetics of both the fashion designer and the consumer. Accordingly, this research study focuses on the analysis of the properties, applications and processing of some natural and manufactured textile fibers, looking forward to enlighten and demystify their ecological character. In consonance, a comparative analysis of cotton and lyocell processing has been done, allowing the observation of the existence of new manufactured fibers that can be envisaged as a sustainable alternative for the production of new textile structures for fashion products. Hence, this dissertation aims to highlight the sustainable character of these new textile structures, demystifying the ecological character of some natural fibers, such as cotton, when confronted with the pollution that re¬sults from its transformation process.

Within the scope of moving towards a circular economy, “green” materials surely represent an excellent alternative, both in terms of sustainable manufacturing process and circular lifespan. For instance, “bio-composites” are promising bio-based materials constituted by bio-polymers or bio-derived polymers that are reinforced by natural fibres or biological wastes and/or residues. The present Internship and Thesis project took place at Mogu S.r.l., a small Italian company (VA) that creates responsible products for interior design. In details, it focused on the production process of bio-composites tiles for flooring from agro-industrial residues like hemp-shives. The current production protocol was firstly implemented through the investigations of macro-variables: particles’ size and distribution, alternative fibres, different %/dry weight of kraft lignin as binder, temperature and pressure, density and thickness. This allowed to cut by almost 38% the total manufacturing time and reduce the amount of bio-adhesive, thus improving the overall sustainability of the process. Then, alternative bio-adhesives have been tested both in a pure form and after pre-treatments. Precisely, some experimental procedures have been developed to denaturise soy and whey proteins, on the basis of methodologies reported in literature. Finally, the most promising bio-composites were further characterized by performing some mechanical tests. Particularly, the tiles with thermally activated whey proteins isolates as binder showed the best flexural properties, far above the threshold values set by norms. Conversely, further studies will be needed to improve panels’ dimensional stability since also the lowest value of swelling in thickness, recorded for panels with kraft lignin and thermally pre-treated, was not in compliance with norms. Nevertheless, the Project confirmed that it is feasible to reach interesting properties with natural components coming from leftovers of several industries.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A flotação catiônica reversa do minério de ferro é um processo de separação usado na mineralogia para separar compostos de ferro de outros compostos indesejáveis presentes no minério de ferro. Nesse processo, o amido é usado como depressor e amina como coletor. A compreensão do mecanismo de interação existente entre os reagentes usados no processo de flotação e o minério de ferro é de fundamental importância para avanços na tecnologia de enriquecimento de minério de ferro, bem como no desenvolvimento de novos agentes químicos usados no processo para esse fim. Esse trabalho está dividido em dois capítulos: i) O primeiro tem como principal objetivo avaliar algumas características do amido que podem influenciar no processo de flotação, como, tamanho da cadeia polimérica e grupo terminal redutor (GTR) presentes na molécula do depressor e ainda avaliar, por meio de técnicas espectroscópicas os minérios flotados e afundados dos testes de flotação usando dextrina, amido solúvel, amido ceroso e amido de milho industrial como agentes depressores. ii) O segundo capítulo tem como principal objetivo desenvolver um novo depressor (XMC), extraído de resíduo de fibra de milho, para substituir o amido no processo de flotação do minério de ferro. Os estudos do capítulo 1 mostraram que moléculas de amido menores resultam piores desempenhos na flotação e que a presença do GTR começa a ser positivamente influente no desempenho da flotação quando se usa moléculas pequenas, em que esse grupo está em maiores quantidades (DE = 10,6% glicose). Uma análise dos espectros de DRIFT baseada na intensidade da banda da hematita não mostrou nada além de que as amostras de concentrado contém mais hematita que as amostras de flotado, como já era esperado. A análise de espectroscopia Raman não possibilitou a observação de qualquer banda característica dos depressores usados, uma vez que só foi sensível à fase inorgânica. Os estudos do capítulo 2 mostraram o grande potencial da XMC em substituição ao amido no processo de flotação, por excelentes resultados de flotação e por ser uma alternativa sustentável, oferecendo uma destinação nobre a um resíduo industrial. Além da possibilidade em remover o amido parcial ou totalmente do processo industrial, preservando-o para a cadeia alimentar humana e animal.
The reverse cationic flotation of iron ore is a separation process used in mineralogy to separate iron compounds from others compounds present in iron ore. In this process, the starch is used as depressant and amine as collector. The knowledge of interaction mechanism between the reagents used in the flotation process and iron ore has a fundamental importance to advance iron ore enrichment technology, as well as to the development of new chemicals used in the process. This work is divided into two chapters: i) The first chapter aims to evaluate some characteristics of starch that can influence the flotation process, such as, size of the polymer chain and reducing end group (REG) present in the depressant molecule. It also aims to evaluate, by spectroscopic techniques, the reject and concentrate minerals from flotation tests using dextrin, soluble starch, waxy starch and industrial corn starch as depressant agents. ii) The second chapter aims to develop a new depressant (XMC), extracted from corn fiber residue (CFR), to replace the starch in iron ore flotation process. The results in Chapter 1 showed that short chain depressant results in worse flotation performance. The amount of REG has no effect on flotation performance up to a dextrose equivalent value of 9.2% glucose. Analysis of the DRIFT spectra based on the intensity of the hematite band only showed the concentrate samples contain more hematite than reject samples, as expected. Using Raman spectroscopy analysis, it was not possible to observe any characteristic band of the depressants used, since the Raman was only sensitive to inorganic phase. The studies in Chapter 2 showed the great potential of XMC replacing starch in flotation process, because of the excellent flotation results and the XMC be a sustainable alternative, offering a prime destination to an industrial waste. Besides, it is possible to remove the starch of industrial process partially or totally, preserving it for human and animal food chain.

Aquesta tesi és una contribució a generar una economia eficient en recursos i energia per mitjà de reccions químiques. En concret, la memòria presenta d’una banda, un procés ràpid i eficaç per a la recuperació de les sals de crom(III) i l'obtenció de biopolimers d'alt valor afegit dels residus cromats procedents de la indústria d’adoberia. El procés de descromació està basat en l'oxidació del crom(III) a crom(VI) utilitzant peròxid d’hidrogen en mitjà bàsic. A més, la mateixa reacció d'oxidació es va utilitzar per recuperar les sals de crom(IIII) dels efluents cromats. D’altra banda, les reaccions termoquímiques (processos d’adsorció química i les reaccions químiques sòlid-gas) obren una nova possibilitat per l’emmagatzematge tèrmic d’energia solar durant períodes llargs de temps en zones residencials. Aquest treball aporta una revisió sobre la investigació experimental de sistemes d’emmagatzematge tèrmic mitjançant materials termoquímics (TCM). A més, la memòria aporta el treball realitzat per a la caracterització experimental del MgSO4•7H2O, Al2(SO4)3•18H2O, CaCl2•2H2O and MgCl2•6H2O per la determinació de la seva aplicació com a TCM en un sistema estacional d’emmagatzematge tèrmic solar. Els resultats experimentals van indicar que els clorurs poden alliberar calor al sistema de calefacció residencial a temperatures més altes que els sulfats.
Esta tesis es una contribución a generar una economía eficiente en recursos y energía por medio de reacciones químicas. En particular esta memoria presenta por una parte, un proceso rápido y eficaz para la recuperación de las sales de cromo(III) y la obtención de biopolímeros de alto valor añadido de los residuos cromados provenientes de la industria del curtido. El proceso de descromación está basado en la oxidación del cromo(III) a cromo(VI) usando peróxido de hidrógeno en medio básico. Además, la misma reacción de oxidación se ha utilizado para la recuperación de las sales de cromo(III) de los efluentes cromados. Por otra parte, las reacciones termoquímicas (procesos de adsorción química y las reacciones químicas sólido-gas) abren una nueva posibilidad para el almacenamiento térmico de energía solar por periodos largos de tiempo en zonas residenciales. Este trabajo aporta una revisión sobre la investigación experimental de sistemas de almacenamiento térmico con materiales termoquímicos (TCM). Además, la memoria presenta el trabajo realizado en la caracterización experimental de MgSO4•7H2O, Al2(SO4)3•18H2O, CaCl2•2H2O and MgCl2•6H2O para la determinación de su aplicación como TCM en un sistema estacional de almacenamiento térmico de energía solar. Los resultados experimentales indicaron que los cloruros pueden liberar calor al sistema de calefacción residencial a temperaturas más altas que los sulfatos.
The current thesis is a contribution to create energy and resource efficient economy by means of chemical reactions. In particular, the thesis presents, on one hand, a quick and effective procedure for recovery of chromium (III) salts and isolation of high added value collagenic biopolymners from chromium(III) tanned solid wastes. The dechroming process is based on the oxidation of chromium(III) to chromium using hydrogen peroxide in alkaline medium. Additionally, the same oxidation reaction was used for recovery of chromium(III) salts from tannery effluents. On the other hand, thermochemical reactions (chemical adsorption processes and solid-gas chemicals reactions) open a new way for long-term solar heat storage in residential areas. The present work gives a review of the experimental research on thermal energy storage systems with thermochemical materials (TCM). Moreover, this work describes the experimental characterisation of MgSO4•7H2O, Al2(SO4)3•18H2O, CaCl2•2H2O and MgCl2•6H2O to determine is suitability for application in a seasonal solar heat storage system. Experimental results showed that the chlorides can deliver heat to the residential heating system at a higher temperature than the sulphates.

Doctor of Philosophy
Department of Grain Science and Industry
X. Susan Sun
A demand in sustainable polymers has been increased because of the environment concerns and saving finite petroleum resources. Plant oils are promising renewable resources to produce environmentally friendly polymer applications. Soybean oil-based resins such as epoxidized soybean oil (ESO) and acrylated epoxidized soybean oil (AESO) have been well-known functionalized plant oils, but relatively low performances of their polymers and a competition with food production have been disadvantages. Thus, in this study, we designed new plant oil-based acrylates using non-food resources and achieved excellent properties of the acrylates for coatings and thermoset applications. Firstly, we developed coating materials with high mechanical, thermal and coating performances using acrylated epoxidized camelina oil (AECO) as a main acrylate monomer with various meth(acrylates) as reactive diluents Next, acrylated epoxidized cardanol modified fatty acids from camelina oil (AECFA) was successfully synthesized, and a phenolic structure with long aliphatic side chains with acrylic groups was obtained. The novel structure of AECFA provided rigidity into its polymer maintained with flexibility, and AECFA coating material showed better performances in terms of all properties such as mechanical, thermal, viscoelastic, and coating performances, as compared to commercial AESO resin. Finally, acrylated epoxidized allyl 10-undecenoate (AEAU) was developed from 10-undecenoic acid, castor oil derivative. The single fatty ester structure with di-functional acrylates of AEAU had very lower viscosity and showed better thermoset performances than those of triglyceride-based acrylates such as AESO and AECO. Thus, AEAU had a potential to an alternative to AESO for thermoset applications.

Development of new biocomposites made with biopolymeric matrixes and biofillers coming from nut shells particles. Evaluation of how these fillers may change the thermal and mechanical properties of the material by changing the type of shell, grain size and quantity. The main properties analysed are: - Wettability of the powders - Melting and glass transition temperature - Degree of crystallinity - Young Modulus - Stress at maximum load and at break - Elongation at maximum load and at break - Hardness - Impact Resistance Finally it is presented a possible application of these new materials in packaging.

A literatura destacada nesta pesquisa considerou que, no contexto organizacional, a inovação teve seu papel reforçado na função de contribuir para o desenvolvimento sustentável. Nesse sentido, o quadro das mudanças climáticas suscita o desenvolvimento de tecnologias sustentáveis e a obtenção de matérias-primas limpas. Dessa forma, esta pesquisa teve como foco de investigação a análise de como ocorre o processo de inovação na cadeia produtiva do plástico verde, ao se substituir um recurso não renovável (a nafta) por um renovável (etanol da cana-de-açúcar), a partir da organização focal sob a ótica da sustentabilidade. Para tanto, a pesquisa foi classificada como exploratória e descritiva e a natureza dos dados versou sobre a abordagem qualitativa. Este trabalho teve como método central o estudo de caso, que compreendeu a realização de treze entrevistas ao longo da cadeia produtiva do plástico verde (considerando a Braskem como a organização focal). A partir da perspectiva da organização focal, o diamante da inovação total foi aplicado ao objeto de estudo desta pesquisa. As características do plástico verde extrapolam a inovação de natureza tecnológica, a sustentabilidade do produto está também atrelada ao uso da matéria-prima renovável (etanol da cana-de-açúcar), evidenciando o fato de o dióxido de carbono ser capturado da atmosfera ao longo do cultivo da cana, permanecendo fixado durante o ciclo de vida do produto. O desenvolvimento dos biopolímeros justifica-se pela finitude do petróleo e de o mesmo agravar as emissões dos gases do efeito estufa. Esse desenvolvimento se deve também às vantagens climáticas tidas para produção de cana-de-açúcar e à extensão de terras disponíveis para o cultivo no território brasileiro. Com base na discussão teórica de que a organização focal é capaz de induzir a inovação em suas cadeias produtivas, buscou-se verificar quais efeitos à montante e à jusante foram desencadeados pela Braskem ao considerar a inovação do plástico verde. Dos spillovers à montante, visualizou-se que, para a produção do plástico verde, a substituição da matéria-prima provocou mudanças expressivas na cadeia suprimentos. A cana-de-açúcar conferiu à cadeia, por meio da captação do dióxido de carbono, a redução das emissões dos gases do efeito estufa. Infere-se que o Código de Conduta para os Fornecedores de Etanol da Braskem foi o principal efeito à montante desencadeado. Os principais efeitos à jusante fomentados pela organização focal conferem a importância ambiental sugerida pelo produto. Clientes potenciais foram identificados pela organização focal e, para os mesmos, foi criado o selo I’m green™, podendo ser considerado um dos principais spillovers à jusante. Na maioria dos casos, a utilização do plástico verde agrega valor aos produtos, o que pode se tornar um diferencial competitivo para as organizações que o utilizam. No caso estudado, evidenciou-se que, a partir de exemplos de ações e práticas, a política de sustentabilidade da organização focal é alicerçada nas três principais dimensões da sustentabilidade. Ademais, a partir da análise do diamante da inovação total, das características do plástico verde e das ações discutidas nos elos em termos de inovação e de sustentabilidade, pode-se avançar na discussão teórica inferindo que o plástico verde pode ser considerado uma inovação sustentável.
The literature highlighted in this research considered that, in an organizational context, innovation has strengthened its role in the function of contributing to sustainable development. Thereby, the climate change scenario adds to the development of sustainable technologies and achievement of clean raw materials. This research has focused on the analysis of how the innovation process occurs in the green plastic supply chain, by replacing a non-renewable resource (naphtha from oil) for a renewable one (ethanol from sugarcane), from the focal organizational, considering the sustainability perspective. Therefore, this research was classified as exploratory and descriptive, due to its qualitative nature. The central method used was a case study; it included thirteen interviews related to the green plastic supply chain (considering Braskem as the focal organization). From the perspective of the focal organization, the diamond of the total innovation was applied to the research. The characteristics of green plastic extrapolate the nature of technological innovation. The sustainability of the product is also linked to the use of renewable input (ethanol from sugar cane), highlighting the fact that the carbon dioxide is captured from the atmosphere over the cultivation of sugarcane, remaining fixed during the life cycle of the product. The biopolymers development is justified by the oil finiteness and its aggravating the greenhouse gas emissions. This development is also due to climate advantages obtained by the production of sugarcane and the amount of available land for cultivation in Brazil. Based on the theoretical discussion of the focal organization, it is able to induce innovation in their supply chains, determining which upstream and downstream effects were initiated by Braskem to consider the green plastic innovation. Based on upstream spillovers, it was visualized that, for the green plastic production, the replacement of the raw material caused significant changes in the supply chain. The sugarcane gave to the chain, by the capture of carbon dioxide, the reduction of greenhouse gas emissions. It is inferred that the Conduct Code for Braskem Ethanol Suppliers was the main upstream factor that triggered these outcomes. The main downstream effects developed by the focal organization are related to the environmental importance suggested by this product. Potential clients have been identified by the focal organization and, for them, the I’m green™ mark was created, which can be considered a major downstream spillover. In most cases, the use of green plastic adds value to the products, which can become a competitive advantage for organizations that use it. In the case studied, it became clear that, from examples of actions and practices, the sustainability policy of the focal organization is sustained on the three main dimensions of sustainability. Moreover, from the analysis of the diamond of the total innovation, the characteristics of the green plastic and the actions discussed in innovation and sustainability perspectives, it can advance the theoretical discussion inferring that the green plastic can be considered a sustainable innovation.

Over the last decade polymeric membranes have emerged as an economically viable treatment option to produce drinking water. Due to higher capital costs, the use of ceramic membranes has generally been limited to industrial applications that deal with challenging water quality. Ceramic membranes are superior to polymeric membranes in their physical and chemical resistance, which allows for higher fluxes and backwash pressures as well as rigorous chemical cleaning. As a result, these membranes can potentially operate for longer periods of time, which can decrease the lifetime cost of the membrane. Furthermore, decreased production costs coupled with an increased desire for economical sustainability may open the door for the use of ceramic membranes in drinking water treatment, particularly for highly polluted waters. The loss of membrane permeability as a result of fouling remains one of the biggest challenges for sustainable membrane operation. Therefore, a thorough understanding of fouling behavior and the identification of key foulants is essential for optimizing membrane performance. However, fouling has not been researched in detail for ceramic membranes in drinking water treatment, particularly ultrafiltration, since most research has focused on ceramic microfiltration membranes combined with coagulation. The thesis is divided into four main stages. The first stage involved developing a factorial design to establish a procedure to determine sustainable flux that can adequately compare the fouling between a ceramic and polymeric membrane without compromising the functional potential or operating parameters of either membrane. In this stage, the significance of three different variables (interval length, increment increase, and a hydraulic backwash) in determining sustainable flux were statistically analyzed following a factorial design and consequently included or removed from the sustainable flux determination approach. The increment increase was not significant while the backwash was the most significant variable. The method established was used in later experiments to allow for a comparison of fouling behavior and performance between a polymeric and ceramic membrane. The second stage investigated the fouling behavior of flat-sheet ceramic membranes with model solutions at constant pressure to identify foulants of concern and likely fouling mechanisms for ceramic membranes as well as perform surface characterization techniques not possible with tubular membranes. In this stage the contributions of different model foulants (bovine serum albumin i.e. a protein, alginate i.e. a carbohydrate, humic acid, and colloidal silica) to reversible and irreversible fouling on a flat-sheet ceramic membrane at constant pressure were quantitatively evaluated. Both single foulant solutions and all possible combinations of mixtures of model foulants were investigated. The bovine serum albumin and humic acid were main contributors to hydraulically irreversible fouling and their removal mechanism is postulated to be largely through adsorption. Colloidal silica was the most influential factor governing fouling behavior and diminished the irreversible fouling effect of these organics, thus increasing hydraulic reversibility. Additionally, synergistic fouling effects were also observed. The third stage investigated the same model solutions with tubular ceramic membranes at constant flux to determine the fouling behavior under different conditions and quantitatively assess the effectiveness of different fouling mitigation techniques. The rate of fouling was very high for bovine serum albumin but extremely low for humic acid; however, they both showed high irreversible fouling. The results obtained were consistent with the previous stage using flat-sheet ceramic membranes; particularly regarding the significant role colloidal silica plays in fouling. The ability to compare these two very different configurations and operating parameters is largely due to the use of a hydraulic backwash in both configurations. Therefore, this highlights the importance of investigating fouling reversibility, especially in simplified experiments. The last stage investigated tubular ceramic fouling behavior and organic matter rejection with surface water at constant flux. Tubular ceramic membrane fouling behavior was investigated for river water. A very high initial organic carbon removal was observed at the initial stages of filtration and after each backwash cycle indicating a high affinity of organics to the membrane surface as well as partially reversible adsorption. Humic acid rejection decreased throughout the filtration cycle. On the contrary, biopolymer rejection remained constant indicating size exclusion as a primary removal mechanism. After several modifications to the design and setup, the sustainable flux method established in Stage 1 could not be applied to the ceramic membrane or to the polymeric membrane using highly turbid water; a few hypotheses were made as to why this occurred. It is likely that one or more variables that were not included in the sustainable flux method were influencing the fouling rate over time. Overall, the robustness of ceramic membranes opens the door for some creative fouling mitigation techniques to be used such as backwash pulses and chemical maintenance cleaning.

Tese no âmbito de Doutoramento em Química, ramo de Fotoquímica e apresentada ao Departamento de Química da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
Os efeitos adversos das actividades humanas têm levado à contaminação da água por uma gama cada vez mais complexa de poluentes emergentes. Estes não são eliminados pelos métodos convencionais de tratamento de água e, através do ciclo hidrológico urbano, podem entrar em águas subterrâneas e superficiais, persistir no meio ambiente, bioacumular-se através da cadeia alimentar e chegar à água potável. Incluem-se nos poluentes emergentes fármacos, pesticidas, plastificantes e vários outros grupos de contaminantes; são revistos nesta tese, alguns dos mais relevantes. A combinação de diferentes tecnologias de tratamento de água pode reduzir significativamente a ocorrência de poluentes no ambiente aquático, diminuindo a exposição aos contaminantes e consequentes condições médicas associadas, levando a uma melhoria da saúde e bem-estar. Esta tese aborda a necessidade de uma solução para o problema da poluição da água. Propõe a descontaminação de águas residuais recorrendo a microalgas, com uma abordagem baseada na geração de biomassa e na sua valorização económica, através de potenciais produtos de valor acrescentado. Esses produtos podem atrair investimentos na tecnologia e, portanto, acelerar o seu desenvolvimento. Em primeiro lugar, avaliou-se a eficácia e eficiência do uso de microalgas na biorremediação de substâncias químicas sintéticas. Foram selecionados para o estudo os fármacos mais frequentemente detectados no ambiente e um representante do principal grupo de pesticidas, caracterizado pela sua toxicidade em insectos benéficos e pela exposição a que está sujeita a população em geral. Subsequentemente, avaliou-se a viabilidade da transformação de biomassa proveniente da biorremediação em produtos ecológicos inovadores. Paralelamente, diferentes métodos analíticos foram optimizados e desenvolvidos para a análise e avaliação de processos e produtos. Dentre estes, destaque-se o desenvolvimento de um método simples e confiável com resposta rápida para detecção e quantificação de lípidos, combinando uma nova sonda fluorescente altamente lipofílica, BODIPY BD-C12, e análise de imagem para determinar o conteúdo lipídico de algas e a produção de lípidos na microalga Nannocloropsis sp .. Os estudos de biorremediação revelaram que a microalga marinha Nannochloropsis sp. remove paracetamol, ibuprofeno, olanzapina, sinvastatina e imidacloprida, apresentando diferentes eficiências. A remoção do paracetamol e ibuprofeno foi significativamente maior em células imobilizadas em álcool polivinílico do que em células livres, após as primeiras 24 horas de cultura. No grupo das células livres, a remoção de olanzapina revelou maior eficiência, sugerindo uma maior afinidade das células à molécula de olanzapina do que ao paracetamol e ibuprofeno. Os estudos de imobilização das células mostraram que, embora o álcool polivinílico seja considerado biocompatível, este inibe a proliferação celular. Experiências com o polímero mostraram a libertação de células das esferas e sua desintegração devido à dissolução do álcool polivinílico. Após o processo de biorremediação, a produção de produtos específicos foi avaliada e otimizada; com a otimização das condições, foi possível alcançar um elevado rendimento de 74% do teor de lípidos na espécie Nannochloropsis sp. e, com as partes restantes das células, foi possível demonstrar a sua aplicação em produtos ópticos avançados. Estes encontram aplicações em lentes oftálmicas, que podem ser usadas em óculos graduados e de sol, tendo potencial para ser a primeira lente verde no mercado. Este estudo fornece um importante primeiro passo na tecnologia de biorremediação recorrendo a microalgas, um entendimento sobre a viabilidade da sustentabilidade num conceito de biorrefinaria de microalgas, com base na economia circular.
Adverse effects of human activity are leading to water contamination by an increasingly complex range of emerging pollutants, which are not readily treated by conventional means, and, through the urban water cycle, can enter ground and surface waters, can persist in the environment, bioaccumulate through the food chain and reach drinking water. These include pharmaceuticals, pesticides, plasticisers and several other groups of contaminants. Some of these compounds are reviewed in this thesis. The combination of different water treatment technologies could significantly reduce the occurrence of pollutants in the aquatic environment, which leads to an improvement of health and well-being by preventing exposure to chemicals and the related diseases arising from contaminated water. This thesis addresses the need for a solution to the problem of treatment of emerging pollutants, and proposes the decontamination of wastewaters using microalgae, with an approach based on the generation of biomass, and on the respective economic valorization. It aims to study the potential of obtaining high value-added products that could attract investment in this field and therefore, accelerate the development of microalgae technology. In the first part of the Thesis, the effectiveness and efficiency of using microalgae in the bioremediation of synthetic chemicals were evaluated. The most frequent pharmaceuticals detected in the environment, and a representative of the major group of pesticides, were selected for the study, based on their respective toxicity to beneficial insects and ubiquitous exposure of the general population. The second stage assessed the feasibility of the transformation of the biomass from bioremediation into innovative bio-based products. In parallel, various methods were optimised and developed for the analysis and evaluation of processes and products. Of these, the most significant one is a simple reliable method with fast response for lipid detection and quantification, combining a new highly lipophilic fluorescent probe BODIPY BD-C12 and image analysis to determine the algal lipid content and the lipid production in the microalga Nannochloropsis sp.. The bioremediation experiments revealed that the marine microalga Nannochloropsis sp. removes the pollutants paracetamol, ibuprofen, olanzapine, simvastatin and imidacloprid with different efficiencies. The removal of paracetamol and ibuprofen after the first 24 hours of culture was significantly higher in polyvinyl alcohol immobilised cells than in free cells. In the group of free cells, the removal of olanzapine revealed a higher efficiency, suggesting more affinity of cells to the molecule of olanzapine than to paracetamol and ibuprofen. The immobilisation experiments showed that, although polyvinyl alcohol is considered to be biocompatible, it inhibits cell proliferation. Also, experiments with the polymer showed the leakage of cells from the beads, and its disintegration due to dissolution of polyvinyl alcohol. After the bioremediation process, the formation of specific products was assessed, and with the optimisation of the conditions it was possible to achieve a high yield of 74 % of lipid content in Nannochloropsis sp. and, with the remaining parts of the cells, it was possible to demonstrate the application of products from microalgae bioremediation in advanced optical products. These find applications in ophthalmic lenses, which can be used on prescription glasses and sunglasses, having potential to be the first green lens in the market. This study provides an important first step in bioremediation using microalgae, and an understanding toward the feasibility and sustainability of the microalgae biorefinery concept, based on the circular economy.
Fundação para a Ciência e a Tecnologia (FCT)

博士
大葉大學
環境工程學系碩士班
105
Improving energy recovery from wastewater is a sustainable approach for wastewater treatment and can be of much interest toward protection and improvement of the water environment. Microbial fuel cell (MFC) technology provides a direct approach to energy production from wastewater streams and is of much interest at the interface of Chemical and Environmental Engineering, Electrical Engineering and Materials Science. Besides its ability for bioelectrical power generation, simultaneous wastewater treatment can be achieved thereby expanding its scopes for application. Albeit MFC technology is promising, a number of hurdles need to be overcome before it can be considered economically and environmentally feasible. Proton exchange membranes (PEMs) are a central component in MFC technology due to the importance of proton transport in facilitating the redox reaction occurring in MFC systems. The development of low cost, environmentally friendly and sustainable PEM materials is still an attractive research area for membrane-based fuel cell technology. This study explored the modification of natural, abundant, low-cost, non-toxic and eco-friendly chitosan (CS) biopolymer toward its application as a viable proton exchange material in MFC systems by blending and crosslinking methods. CS was blended with sorbitol and sodium alginate, and filled with graphene oxide to form CS-based plasticized, polyelectrolyte and mixed-matrix proton exchange membranes (PEMs) respectively, and crosslinked with phosphoric and sulfuric acid groups. Extensive physicochemical, thermal and mechanical characterization of the synthesized CS-based PEMs through FESEM-EDS, FTIR-ATR, XRD, TGA, tensile strength, cation exchange capacity and sorption studies indicated that blending solutions and crosslinking agents potentially influenced the physicochemical properties suitable for improved fuel cell performance of CS in terms of bioelectricity production and wastewater treatment. Modification prior to membrane formation proved effective for reducing membrane stress of the rigid CS structure, increasing polymer chain flexibility and promoting interfacial formations. Interrogation of the crosslinked CS-based PEMs demonstrated that ionic crosslinking based on the incorporation of PO43- groups in the CS matrix, when compared with sulfuric acid crosslinking commonly used in MFC studies, generated additional density of ionic cluster domains, rendered enhanced membrane sorption behaviour and augmented the thermal and mechanical stability of the PEM structure. Consequently, maximum power density of pristine unmodified chitosan improved from 32.96 mW/m3 to 257, 349.22 and 451.35 mW/m3 using the modified CS-based PEM synthesized by crosslinking with phosphoric acid for 24 h (CS-P(24)), filled with graphene oxide CS-GO(5)-P(24) and blended with alginate CS-Alg(1:1)-P(24) respectively; furthermore, a maximum of 89.52% COD removal of primary clarifier municipal wastewater was achieved in the MFC operated with the mixed-matrix crosslinked CS-GO-P(24) membrane. The MFCs operated with modified CS-based PEMs exhibited enhanced performance. Thus, through modifications, the physicochemical and mechanical properties of natural abundant biopolymer chitosan can be enhanced for its use as an environmentally sustainable PEM in MFC technology.