nÃo hà / Solar desalination plants are used for water treatment using solar radiation as an energy source, but its incidence varies, either in terms of time, the weather, the seasons or the presence of clouds. These factors complicate the understanding of the process variables influence and constructive geometric parameters. In this work, the experimental results, obtained by operation with a thermal desalination unit with heat recovery, are presented. The process occurs by controlled heating, by electricity flowing through a resistance present at the base of desalination tower (storage tank). In addition to the tank, the tower also comprises stages, consisting of polyurethane profiles, to prevent heat loss to the external environment, and aluminum trays in W format, through which flows the water generated by the steam condensation from the next lower stage. On the sides of each stage profiles, there are condensate collection gutters connected to hoses that lead the produced fluid to collection canisters. The production of desalinated water, with the use of a hydrophobic film on the bottom of the aluminum trays, where the condensate drains, was evaluated. Also biological, physical and chemical, chromatographic and spectrometric tests were conducted in order to verify the quality of the water produced. The best desalinator operating condition of the study, with the maximum output gain ratio (GOR) for the system of 7.92, was obtained with a potential difference of 120V, 600W power and five stages in the desalination tower. The film did not increase the water production, but it was also not observed contamination of water samples by the hydrophobic product. / Dessalinizadores solares sÃo empregados para tratamento de Ãgua utilizando-se a radiaÃÃo solar como fonte de energia, porÃm sua incidÃncia varia, seja em funÃÃo do horÃrio, do clima, das estaÃÃes do ano ou da presenÃa de nuvens, o que dificulta o conhecimento da influÃncia das variÃveis de processo e dos parÃmetros geomÃtricos construtivos. Nesta dissertaÃÃo, os resultados experimentais, obtidos atravÃs de operaÃÃo com um dessalinizador tÃrmico, com recuperaÃÃo de calor, sÃo apresentados. O processo ocorre por meio de aquecimento controlado, atravÃs de energia elÃtrica que passa por uma resistÃncia presente na base da torre de dessalinizaÃÃo (tanque de armazenamento). AlÃm do tanque, a torre tambÃm à composta por estÃgios, que consistem em perfis de poliuretano, para evitar a perda de calor com o meio externo, e bandejas de alumÃnio, em formato de W, por onde escoa a Ãgua gerada pela condensaÃÃo do vapor proveniente do estÃgio imediatamente inferior. Nas laterais dos perfis de cada estÃgio, existem calhas de coleta do condensado, ligadas a mangueiras que conduzem o lÃquido produzido a vasilhas de coleta. Avaliou-se a produÃÃo de Ãgua dessalinizada com o uso de uma pelÃcula hidrofÃbica, na parte inferior das bandejas de alumÃnio, por onde o condensado escoa. TambÃm foram realizados testes biolÃgicos, fÃsico-quÃmicos, cromatogrÃficos e espectromÃtricos, a fim de verificar a qualidade da Ãgua produzida. A melhor condiÃÃo de operaÃÃo do dessalinizador em estudo, com mÃxima RazÃo de Ganho de SaÃda (GOR) para o sistema, de 7,92, foi obtida com uma diferenÃa de potencial de 120V, potÃncia de 600W e cinco estÃgios na torre de dessalinizaÃÃo. A pelÃcula nÃo aumentou a produÃÃo de Ãgua, mas tambÃm nÃo foi constatada contaminaÃÃo das amostras de Ãgua pelo produto hidrofÃbico.

A funcionalização de materiais poliméricos para a produção de superfícies superhidrofóbicas é importante para uma série de aplicações, principalmente as associadas com superfícies autolimpantes e anti-aderentes. Uma abordagem para obter superhidrofobicidade é combinar polímeros hidrofóbicos com outros materiais passíveis de ser microestruturados. Neste estudo, copolímeros hidrofóbicos foram sintetizados através de polimerização radicalar convencional usando os monômeros 2,2,3,3,4,4,5,5 octafluorpentil metacrilato (OFPMA) ou 2,2,2 trifluoretil metacrilato (TFEMA) copolimerizado com o azo monômero 4-[N-etil-N-(2-metacriloxi-etil)]amino-4-nitro-azobenzeno (DR13-MA) em proporções distintas. A polimerização foi bem sucedida, apresentando massas molares acima de 10.000 g / mol, com uma polidispersividade relativamente baixa. Os copolímeros e homopolímeros, derivados de OFPMA e TFEMA - usados para comparação tiveram sua estrutura confirmada através de espectroscopia no infravermelho (FTIR) e ressonância magnética nuclear (RMN). A proporção de azo monômero incorporada foi estimada por RMN e espectroscopia no UV-vis e foram condizentes com a relação utilizada, ou seja, 10, 20 e 30% em massa. Foram formados filmes de Langmuir estáveis dos copolímeros na interface ar / água, cuja isoterma de pressão superficial apresentou transição de fase provavelmente atribuída a um rearranjo molecular. O potencial de superfície dos filmes dos copolímeros foi negativo, o que indica que os átomos de flúor estavam direcionados para o ar. Esta organização molecular foi mantida após a transferência de filmes sobre substratos sólidos na forma de filmes Langmuir-Blodgett (LB), formando superfícies hidrofóbicas com ângulos de contato próximos de 90 º para todos os copolímeros, independentemente do número de camadas depositadas. A natureza organizada dos filmes LB não contribuiu para a hidrofobicidade, pois o ângulo de contacto é semelhante ao obtido com filmes cast. Grades de relevo foram inscritas nos filmes cast, mas o ângulo de contato não foi afetado significativamente. Portanto, uma otimização na inscrição de nanoestruturas será necessária para se alcançar a superhidrofobicidade. / The functionalization of polymer materials to produce superhydrophobic surfaces is an important goal for a number of applications, especially those associated with self-cleaning and anti-adherent surfaces. A possible approach to achieve superhydrophobicity is to combine hydrophobic polymers with other materials amenable to be microstructured. In this study, hydrophobic copolymers were synthesized through conventional radicalar polymerization using the monomers 2,2,3,3,4,4,5,5 octafluorpenthyl methacrylate (OFPMA) or 2,2,2 trifluorethyl methacrylate (TFEMA) copolymerized with the azomonomer 4-[N-ethyl-N-(2methacryloxy-ethyl)]amine-4-nitrobenzene methacrylate (DR-13MA) in distinct proportions. Polymerization was successful leading to molar masses above 10,000 g/mol, with a relatively low polydispersity. The copolymers and the homopolymers from OFPMA and TFEMA used for comparison had their structure confirmed with Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) measurements. The proportion of azomonomer incorporated estimated via NMR was consistent with that determined with UV-vis. spectroscopy for the relative concentrations used, namely 10, 20 and 30% in mass. The copolymers formed stable Langmuir films at the air/water interface, whose surface pressure isotherms featured a phase transition probably associated with molecular rearrangement. The surface potential of the condensed copolymer Langmuir films was negative, which indicates that the fluorine atoms were directed toward the air. This molecular organization was maintained upon film transfer onto solid substrates in the form of Langmuir-Blodgett (LB) films, leading to hydrophobic surfaces with contact angles close to 90º for both copolymers, which did not depend on the number of layers deposited. The organized nature of the LB films did not contribute to the hydrophobicity, however, as similar contact angles were measured for the cast films made with the copolymers. Surface-relief gratings could be inscribed on the cast films, but the contact angle was not affected significantly. Therefore, an optimization in the inscription of such nanostructures will be required for achieving superhydrophobicity.

Neste trabalho, duas preparações de lipase imobilizada (EC 3.1.1.3), tipo B (CALB) de Candida antarctica, foram comparadas como biocatalisadores na síntese de ésteres metílicos. CALB imobilizada comercialmente (Novozym 435 - CALB-435) e CALB imobilizada em esferas de estireno-divinilbenzeno (CALB-MCI) foram testadas para as reações de transesterificação. Um delineamento composto central rotacional (DDCR) e metodologia de superfície de resposta (MSR) foram utilizados para otimizar a relação razão molar álcool:óleo, teor de enzimas, e a água adicionada nas reações. As duas preparações de enzimas mostraram diferentes condições ótimas para a produção de ésteres metílicos, com a taxa inicial da reação de 51,47 mmol L-1 h-1 para CALB-435, e 57 mmol L-1 h-1 para CALB-MCI. O estudo do tempo de reação indicou que em 72 h foi possível obter conversões próximas a 100 % para ambos os derivados. Um alto rendimento de conversão foi obtido sob as condições otimizadas, indicando que a RSM pode ser usada para descrever adequadamente a relação entre os parâmetros de reação e da resposta (teor de ésteres metílicos). Sobre a estabilidade operacional durante as experiências de reutilização, ambos preparados enzimáticos mantiveram 70 % de sua atividade inicial após oito bateladas, sugerindo sua aplicabilidade na produção de biodiesel. / In this work two preparations of immobilized lipase (EC 3.1.1.3), type B (CALB) from Candida antarctica, were compared as biocatalysts in the synthesis of esters. Commercial Novozym 435 (CALB-435) and CALB immobilized on styrene-divinylbenzene beads (CALB-MCI) were tested for the transesterification reactions. Central composite design rotational (DCCR) and response surface methodology (RSM) were used to optimize the substrate molar ratio, enzyme content, and the added water. The two enzyme preparations have shown different optimal conditions for the production of methyl esters, with initial rates of reaction 51.47 mmol L-1 h-1 for CALB-435, and 57 mmol L-1 h-1 for CALB-MCI. The study of reaction time indicated that in 72 h it was possible to obtain conversions close to 100 % for both derivatives. A high yield conversion was obtained under the optimized conditions, indicating that RSM can be used to adequately describe the relationship between the reaction parameters and the response (yield conversion) in lipase-catalyzed biodiesel synthesis. Over the operational stability during experiments of batch reuse, both prepared enzymatic maintained 70 % of their initial activity after eight batches, suggesting their potential for economical application on biodiesel production.

Orientador: Cesar Costapinto Santana / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-07-27T02:38:10Z (GMT). No. of bitstreams: 1 Veredas_Vinicius_M.pdf: 4752847 bytes, checksum: f01c509a2798835914e0489d2f75baac (MD5) Previous issue date: 2000 / Resumo: O crescente interesse e aplicações dos produtos biotecnológicos vem aumentando o desenvolvimento de novos processos de recuperação e purificação de proteínas. O soro de leite bovino, obtido da manufatura da caseína para a produção de queijo, é em sua maioria descartado em mananciais de água, causando sérios problemas ambientais devido a sua alta demanda biológica de oxigênio (DBO). As proteínas presentes no lactosoro apresentam um excelente valor nutritivo e farmacológico, porém, o seu uso no enriquecimento de produtos alimentícios é limitado devido a baixa concentração destas proteínas. As principais proteínas do lactosoro são: ~-Iactoglobulinas, a-Iactalbumina, albuminas de soro bovino, imunoglobulinas, lactoperoxidase, lactoferrina, lisozima e outras proteínas de menor proporção, que apresentam um alto valor agregado. A a-Iactalbumina atua no organismo estimulando os agentes do sistema imunológico por proporcionar a elevação de glutationa em vários órgãos e no sangue, resultando em benefícios para pacientes portadores de doenças degenerativas como os males de Parkinson e Alzheimer, câncer e AIDS. Neste trabalho foi estudado o processo de separação da a-Iactalbumina, através de técnicas cromatográficas empregando a metodologia de leito fixo e expandido. O leito expandido possibilita a redução nos custos do processo de purificação, eliminando etapas de separação necessárias quando o extrato apresenta material em suspensão, que é o caso dos lactosoros. Nos ensaios realizados foram estudados as melhores condições de adsorção da a-Iactalbumina visando a sua purificação empregando adsorventes de troca iônica e de interação hidrofóbica. Também foram realizados ensaios em sistemas de tanque agitados para a determinação das isotermas e cinéticas de adsorção. Neste trabalho obteve-se a a-Iactalbumina com uma pureza acima de 80% e apresentando um fator de purificação de 5 vezes utilizando as resinas de interação hidrofóbica com única etapa de purificação / Abstract: The interest and applications of biotechnology products has been increasing the development of new recovery and purification processes for proteins. The bovine milk serum, obtained from casein manufacture for cheese production, is mostly rejected into watercourse, causing problems to the environment due to its high biological oxygen demand (BOD). The proteins of milk serum have excellent nutritious and pharmaceutical value, h oweve r, its application for protein enrichment of food products is limited due to its low content in the milk serum. The main proteins of milk serum are: ~-Iactoglobulins, a-Iactalbumine, bovine serum albumine, immunoglobulins, lactoperoxidase, lactoferrin, lisozime and other lower content proteins which have a high aggregate value. The a-Iactalbumine acts in the human organism by stimulating the agents of the immunologycal system due to increasing on glutathione levei in several organs and blood, resulting in benefits for patients of some diseases like Parkinson and Alzheimer's iII, cancer and AIDS. It was studied in this work the separation processes of a-Iactalbumine, by chromatographic techniques making use of fixed and expanded bed methods. The expanded bed enables cost reduction on purification process by reducing separation steps used for removing suspended solids, as in case of milk serum extracts. In our experiments were studied the adsorption conditions of alactalbumine aiming at its purification by using ionic exchange and hydrophobic interaction adsorbents. Other experiments were accomplished at stirred tank systems for the determination of isotherms and adsorption kinetics. It was obtained, in this work, an a-Iactalbumine purity higher than 80%, with a five fold purification factor by using the hydrophobic interaction resins in a single purification ste / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

Activated carbons have been modif fed using reactive chemicals to produce adsorbents of enhanced hydrophobic character which will also be resistant to surface oxidation that results from exposure to humid air ("ageing"). The intention was that modification would not disrupt the carbon pore structure. The adsorptive properties of the modified carbons have been investigated using probe molecules Including nitrogen, water, hexane, and chloropicrin, and the ageing characteristics of the carbons, and the factors controlling the adsorption of a model hydrophobic vapour from high humidity air have been studied. Directly fluorinated carbons were unstable, probably due to weakly adsorbed fluorine. Treatment of these adsorbents with other chemicals indicated the potential of the technique for Introducing specific functional groups onto the carbon surface. Carbons modified using selective fluorinating reagents (hexafluoropropene and 1,1-difluoroethene) were more hydrophobic, and adsorbed hydrophobic vapours more efficiently from humid air in comparison to controls. These adsorbents aged, but at a reduced rate in comparison to control carbon. Carbons modified using chlorinating reagents (carbonyl chloride and chlorine) and treated with solvents to remove adsorbed reagent and/or reaction products were of improved hydrophobic character, and adsorbed hydrophobic vapours from humid air at least as efficiently as the control samples. More importantly, these carbons offered resistance to ageing effects. A study of the factors controlling the efficiency with which hydrophobic vapours; are adsorbed from humid air revealed that the surface chemistry of the carbon is important, but that under typical conditions of use, filter performance was limited by the rate at which water displaced by the organic vapour could be carried away by the airstream. The results illustrate that filters containing chemically modified activated carbon offer advantages when volatile hydrophobic contaminant vapours are present, and where ageing effects are an important mechanism by which filtration efficiency is degraded.

In this study, commercially available isotactic polypropylene (PP) and nylon-6 (PA6) blends and laminates were prepared, to develop a material with optimal water vapour and oxygen barrier properties. The effect of compatibilizers on phase dispersion has been investigated using three commercial Polybond's, PB3002, PB1001, and PB3009. Three compatibilizers prepared in-house were also used as, maleic anhydride(MA) grafted on PP, MA and butyl methacrylate(BMA) co-polymer grafted on PP, and BMA grafted on low density polyethylene. The effect of two silanes( methacrylate functional and vinyl functional) on PP were also investigated and also the plasticization of PA6 with formic acid. The results were compared with a commercial blend of PP and PA6, Orgalloy R-6000. Light microscopy with phase and fluorescence contrast has been used for morphological evaluation. Chemical changes were studied by Fourier Transform Infrared Spectroscopy and rheology by dynamic and steady state measurements. Barrier properties were determined gravimetrically for water vapour and organic solvents, and for oxygen by an Oxtran apparatus. The results have shown that phase dispersion can be more easily explained by molecular interactions than by the rheological parameters. The blend slip factor has been improved however by compatibilizers and consequently the phase dispersion, which had little effect on the barrier properties of the blends and indeed the laminates were more effective water vapour barriers. The availability of particular functional groups, which can interact with the permeant is the most important parameter, which can be affected by processing and blending conditions. The addition of hydrophobic functional groups into polypropylene was therefore the most effective method for enhancing the barrier properties of polypropylene. Cross-linking of the matrix polymer has improved the barrier properties to a lesser extent. It has also been shown, that PP solvent permeability (particularly di-chloromethane) can be improved, by silane addition.

The biggest challenge with magnesium alloy biodegradable implants is the rapid corrosion at the earlier stages of the healing process after implantation. In this research, the impact of surface roughness generated by different means on the corrosion rate of AZ31 magnesium alloy in a simulated biologic environment is investigated. In order to perform accurate experimentation, an in vitro setup is assembled that simulates the human body environment accurately has been prepared using Schinhammer’s in vitro immersion testing setup and Kokubo’s Simulated Body Fluid (SBF). For the immersion test of Mg in SBF, several surface texture groups of Mg have been prepared and submerged into the in vitro tank. The Mg samples’ comparative analysis has been made in terms of corrosion rate, total weight loss and hydrogen gas evolution within a span of 7 days for the first experiment to narrow down the scope and 14 days for the follow up experiment. After 14 days of in vitro immersion test with varying roughness and hydrophobic modifications such as Cytop coating and stearic acid modification, it has been observed that the roughness group created by etching in aqueous NaCl solution for three minutes, shows better corrosion resistance compared to the polished control group. Hydrophobic modifications on the surfaces did not affect the corrosion behavior significantly.

It was the objective of this project to provide a glass cleaner formulation for a wet wipe application with cleaning and anti-fogging properties. This glass cleaner formulation was developed for automotive glass i.e. interior of windscreens. This formulation relates to a glass cleaner with a composition comprising of: (a) a blend of amphoteric surfactants; (b) a solvent system with a combination of glycol ethers; and (c) an aqueous solvent system. This glass formulation must provide good cleaning properties while also providing good wetting and sheeting properties to assist with anti-fogging properties. The objectives were obtained using 2 specific approaches: The first was by using a blend of 2 amphoteric surfactants in an alkaline medium, allowing the glass surface to become more hydrophilic which will also assist with reduction of surface tension on the glass surface. The second was by using the glycol ethers that have good coupling properties and surface tension reducing properties. The formulation was evaluated using commercial standard test methods as per the industry. A predictive model was successfully obtained for each of the five criteria that were evaluated using the 25 formulations derived from the statistical design. There were variables and variable interactions that were antagonistic for some of the criteria which were found to be synergistic for others. To achieve satisfactory cleaning, the fogging rating had to be compromised.

Bottom sediments around the world store large amounts of legacy hydrophobic organic contaminants (HOCs), forming mixtures of unknown chemical composition. Primary emissions to the environment of many HOCs have been reduced as a consequence of regulation. However, HOCs may be released from the sediments to water and biota, and there is therefore a risk of negative effects on local ecosystems. The activity of benthic organisms can enhance the sediment-to-water flux of HOCs, a process called bioturbation. Few in situ assessments of the sediment-to-water flux are available in the scientific literature, and the effect of bioturbation on the sediment-to-water flux of HOCs has not been studied in the field. Thus, there is a need to improve in situ methods for direct determination of sediments as a source of HOCs to water, and thereby include the effect of bioturbation. In Paper I, a benthic flow-through chamber was developed for environmentally realistic in situ assessments of the sediment-to-water flux. In Paper II, the sediment-to-water flux of polycyclic aromatic hydrocarbons (PAHs) was assessed using the flow-through chamber at four sites on the Swedish Baltic Sea coast. The sediments at all four sites acted as sources of PAHs to water. In the same study, potential effects of bioturbation, with an increase of the sediment-to-water flux by up to one order of magnitude, were observed at sites with bioturbating organisms. In the past, assessing the toxicity of HOCs has been challenging due to difficulties in maintaining stable exposure concentrations of the test chemical. In Paper III, a passive dosing method, where the test chemical partitions from a polymer (silicone) to the aquatic exposure medium, was developed and tested for chronic exposure. A stable exposure concentration could be maintained, and the chronic toxicity to the sediment-dwelling harpacticoid Nitocra spinipes of chronic exposure to triclosan was assessed in a 6-week population development test. In Paper IV, a passive sampling and dosing method was developed and used to assess the toxicity of an environmental chemical mixture of bioavailable sediment-associated HOCs transferred from a contaminated sediment to the laboratory-based bioassay. The passive sampling and dosing method can be used to assess the toxicity of environmental mixtures of chemicals at environmentally realistic concentrations to which ecosystems are constantly exposed. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.</p>

The cryopreservation of cells and tissues requires the addition of a cryoprotectant in order to prevent cellular damage caused by ice. Unfortunately, common cryoprotectants such as DMSO and glycerol exhibit significant toxicity which makes their use unfeasible for many clinical procedures. Our laboratory is interested in the development of alternative, non-toxic cryoprotectants which possess ice recrystallization inhibition (IRI) activity. Potent IRI activity has recently been discovered in certain small molecules, but the structural features required for this process are unclear. Herein we report the development of a library of O-aryl glycosides in order to probe the importance of electron density and hydrophobic moieties for IRI activity. It was found that the degree of electron density at the anomeric oxygen does not correlate with IRI ability in para-substituted aryl glycosides, nor does changing the position of the aryl substituent impart a predictable effect on activity. However, the addition of hydrophobic alkyl or acyl chains was beneficial for IRI activity; generally, increasing chain length was found to correlate with increasing activity. In some instances, an optimal alkyl chain length was identified, after which continued lengthening results in a loss of potency. We conclude from this study that a certain extent of hydrophobic character is beneficial for the IRI activity of aryl glycosides, and that a balance between hydrophobicity and hydrophilicity is required for optimum IRI ability. It is hoped that these findings will aid future efforts towards the rational design of novel cryoprotectants.