Orientador: Everson Alves Miranda / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-17T00:24:12Z (GMT). No. of bitstreams: 1 Silva_AlanHenriqueda_M.pdf: 1835038 bytes, checksum: 8f53d7e3503d526bab0e9fb0f812bd6c (MD5) Previous issue date: 2010 / Resumo: Fermentações para a produção de ácidos orgânicos se mostram cada vez mais importantes em química e petroquímica verde, seja devido a uma futura escassez de petróleo (base de produção destas moléculas) ou pelo apelo ambiental. Há alguns anos, estes processos biotecnológicos não eram economicamente viáveis, devido principalmente às etapas de recuperação e purificação das biomoléculas (RPB), sendo estas um forte componente no custo de produção. Seu estudo se torna então de suma importância para reduzir custo e aumentar a viabilidade técnico-econômica destes bioprocessos. A adsorção se mostra uma operação unitária muito estudada, robusta, de fácil escalonamento e operação, o que a torna uma opção atrativa para a RPB de tais ácidos. No entanto, estudos existentes até o momento não são completos necessitando uma maior abrangência para se desenvolver um processo eficiente. Com base neste quadro, este trabalho visou o estudo experimental de adsorção, em carvão ativado e resinas poliméricas de aplicação industrial, de ácidos orgânicos passíveis de produção por via fermentativa e de relevância em petroquímica verde. Isotermas de adsorção dos ácidos acético, propiônico e butírico foram avaliadas para verificar o efeito de temperatura, água, etanol e n-propanol utilizando sistemas monocomponentes e binários. Modelos de isotermas de adsorção foram avaliados quanto ao ajuste aos dados experimentais para ambos os sistemas. Os estudos de adsorção monocomponente mostraram que as resinas têm capacidade de adsorção maior que os carvões (cerca de 35%). A temperatura apresentou efeito pouco significativo na adsorção. Os estudos de adsorção de sistemas binários dos ácidos estudados identificaram que houve competição entre estes na adsorção, onde moléculas de maior cadeia carbônica têm uma maior afinidade pela superfície do adsorvente. Nos estudos de isotermas de adsorção utilizando etanol e propanol como possíveis solventes para dessorção, a resina apresentou altos valores de adsorção, ao contrário dos carvões. Uma simulação dos processos de adsorção e dessorção mostrou que a resina PLA133 apresentou melhores resultados como adsorvente e o propanol como melhor eluente, em um processo de dessorção de três estágios em contra-corrente. No entanto, a recuperação final do ácido, sendo o melhor resultado 70%, pode não ser satisfatória, dependendo da aplicação deste, de forma que ainda pode ser necessário uma melhoria no processo. / Abstract: Fermentations for the production of organic acids are becoming very important in green chemistry due to a future scarcity of oil (base of production of these acids) and environmental protection. A few years ago, these biotechnological processes were not economically viable mainly due to the downstream process (DSP) stages which are a strong component of production costs. The study of these bioprocesses becomes very important to increase their technical and economic feasibility. Adsorption - a widely studied unit operation - is robust and easy to operate, so it is an attractive option for the DSP of organic acids. However, current studies reported in the literature about this subject are not complete and therefore more through integrated studies need to be associated to develop an efficient process. The present work is an experimental study about adsorption of organic acids of relevance in green chemistry. Industrial activated carbons and polymeric resins (weak base resins were used as adsorbents. Equilibrium adsorption studies in single and binary systems of acetic, propionic and butyric acids were carried out to evaluated the effect of temperature and solvents (water, ethanol and n-propanol) on the adsorption. Equilibrium isotherm models were tested to represent the data in single and binary systems. The adsorption studies showed that resins had a higher adsorption capacity than activated carbons (about 35%). Adsorption in single systems was not significantly affected by temperature in the studied range. Data from adsorption of binary systems suggested that there was competition between the acids and the affinity of the acids for the surface is dependent on acids carbon chain size. In studies using ethanol and propanol as desorbents, the resin showed a high adsorption capacity, unlike the activated carbons. A simulation of the adsorption unit operation showed that the resins yielded better results than activated carbons; propanol was the best eluent in a three-stage counter-current desorption process. However, the best acid recovery of 70% may not be satisfactory depending on the application of the acid, so it can be necessary to improve the process for better results. / Mestrado / Mestre em Engenharia Química

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Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15374号 / 工博第3253号 / 新制||工||1490(附属図書館) / 27852 / 京都大学大学院工学研究科原子核工学専攻 / (主査)教授 森山 裕丈, 教授 山名 元, 准教授 佐々木 隆之 / 学位規則第4条第1項該当

As long ago as 1881, it was realized that a functional group of atoms in a molecule would cause an absorption band to appear at a particular frequency in the infrared spectrum of the molecule. In more recent years, the concept of characteristic group frequencies has become firmly established and has resulted in the present widespread use of infrared spectroscopy. There appear to have been relatively few studies of infrared absorption of organic acids as compared with their salts.

Orientador: Gustavo do Valle Polycarpo / Resumo: A restrição do uso de antibióticos e quimioterápicos na alimentação animal, alavancada pela União Europeia em 2006, provocou um aumento nas pesquisas em busca de aditivos alternativos sobre o desempenho de frangos de corte. Objetivou-se desenvolver uma meta-análise de ácido butírico como melhorador de desempenho em alternativa aos antibióticos sobre o desempenho de frangos de corte. A busca digital por estudos incluiu artigos científicos publicados na base de dados Scopus nos anos de 2014 a 2019 por meio de três principais palavras-chave broiler, butyric acid e performance, e seus sinônimos. Foram selecionados artigos descrevendo experimentos in vivo com frangos de corte, suplementados com ácido butírico com respostas de desempenho. Os dados foram sistematizados em planilhas eletrônicas e classificados de acordo com o tipo de desafio sanitário (sem ou com inoculação de microrganismos patogênicos). Ao todo foram utilizados 36 experimentos para avaliar o efeito do ácido butírico. Com base em 36 estudos foram criados dois ensaios, um primeiro considerando o tratamento controle contra o tratamento suplementado com ácido butírico e um segundo ensaio considerando-se apenas 10 experimentos, os quais também continham um tratamento controle positivo contendo antibiótico para avaliar o efeito do ácido butírico como alternativa aos promotores de crescimento (ensaio 2). A análise estatística foi realizada por meio do software SAS University Edition, versão 9.4. Foi utilizado um modelo mi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The restriction of the use of antibiotics and chemotherapy in animal feed, leveraged by the European Union in 2006, caused an increase in research in search of alternative additives on the performance of broilers. The objective was to develop a meta-analysis of butyric acid as a performance enhancer as an alternative to antibiotics on broiler performance. The digital search for studies included scientific articles published in the Scopus database in the years 2014 to 2019 through three main keywords broiler, butyric acid and performance, and their synonyms. Articles were described describing in vivo experiments with broilers, supplemented with butyric acid with performance responses. The data were systematized in electronic spreadsheets and classified according to the type of health challenge (without or with inoculation of pathogenic microorganisms). Altogether 36 experiments were used to evaluate the effect of butyric acid. Based on 36 studies, two trials were created, a first considering the control treatment against treatment supplemented with butyric acid and a second trial considering only 10 experiments, which also contained a positive control treatment containing antibiotics to evaluate the effect of the acid butyric as an alternative to growth promoters (trial 2). Statistical analysis was performed using the software SAS University Edition, version 9.4. A mixed model was used through the MIXED procedure, in which the effect of each experiment was considered as a clas... (Complete abstract click electronic access below) / Mestre

Orientador: Eleni Gomes / Resumo: O conhecimento das propriedades inerentes aos microrganismos assimiladores de pentoses deve ser obtido para que se desenvolva novas possibilidades de aplicação da biomassa lignocelulósica. A hemicelulose (polissacarídeo rico em pentoses) corresponde em média 25 % da massa da biomassa vegetal e sua hidrólise gera uma mistura de xilose e arabinose. Muitas leveduras, que utilizam pentoses como fonte de carbono, poderiam ser utilizadas direta ou indiretamente (através da expressão heteróloga de seus genes) na bioconversão dessas pentoses em combustível ou em outros produtos de elevado valor mercadológico. Portanto, o objetivo desse trabalho foi avaliar o potencial das cepas Sporidiobolus pararoseus U3, Pichia terricola G20 e Metschnikowia koreensis G18 de crescerem em xilose e arabinose nos pHs 4,5, 6,5 e 8,5, nas temperaturas 29 e 32 °C, na presença de compostos potencialmente tóxicos (8 compostos em três concentrações cada) e em hidrolisados de bagaço de cana. Dados sobre o efeito do pH, nutrientes e oxigenação e fontes de nitrogênio (nitrato de amônio, sulfato de amônio e ureia) em diferentes concentrações no crescimento e produção de ácidos orgânicos foram obtidos para da cepa M. koreensis G18. Todas as leveduras foram capazes de crescer em todos os pHs testados, com destaque as cepas M. koreensis G18 e P. terricola G20, uma vez que a primeira cresceu consideravelmente tanto em 29 °C como em 32 °C e a segunda por crescer mais rápido com arabinose, embora somente a 32 °C. A me... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The knowledge of the properties inherent to the pentoses assimilating microorganisms must be obtained in order to develop new possibilities for the application of lignocellulosic biomass. The hemicellulose (polysaccharide rich in pentoses) corresponds in average 25 % of the mass of the vegetal biomass and its hydrolysis generates a mixture of xylose and arabinose. Many yeasts, which use pentoses as a carbon source, could be used directly or indirectly (through the heterologous expression of their genes) in the bioconversion of these pentoses to fuel or other products of high market value. Therefore, the aim of this work was to evaluate the growth potential of strains Sporidiobolus pararoseus U3, Pichia terricola G20 and Metschnikowia koreensis G18 to grow in xylose and arabinose at pHs 4.5, 6.5 and 8.5 at temperatures of 29 and 32 °C in the presence of potentially toxic compounds (8 compounds in three concentrations each) and sugar cane bagasse hydrolysates. Data on the effect of pH, nutrients and oxygenation and sources of inorganic nitrogen (ammonium nitrate, ammonium sulfate and urea) at different concentrations in the growth and production of organic acids were obtained for the strain M. koreensis G18. All yeasts were able to grow in all tested pHs, with emphasis on the M. koreensis G18 and P. terricola G20 strains, since the former grow considerably both at 29 °C and at 32 °C and the second grow at a faster rate with arabinose, although only at 32 °C. The best pentose an... (Complete abstract click electronic access below) / Doutor

>Magister Scientiae - MSc / This study presents the successful characterization and hydrolysis of magnesium hydride (MgH2) for hydrogen generation. The as-received MgH2 served as a precursor in most of the hydrolysis experiments for H2 generation. The phase-structural and morphological characteristics of the as-received MgH2 were evaluated using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray dispersive diffraction (XRD) characterization techniques. The hydrogen storage performance of the as-received MgH2 was analysed by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and thermal desorption spectroscopy (TDS) techniques. The hydrolysis of MgH2 was performed in a hydrogen generation reactor operated in a batch mode where the temperature and H2 flow rate were logged.

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Trace metal concentrations in soil solution, and hence trace metal bioavailability and toxicity, are primarily controlled by sorption/desorption reactions at the mineral-water interface. While numerous studies have been conducted to understand the initial adsorption of these metals to soil minerals, less in known about long-term adsorption/ desorption processes. The objective of this study was to examine the influence of residence time and organic acids on the desorption of Pb2+and Cd2+ from goethite. Adsorption experiments were conducted at pH 6.0. Lead adsorption was nearly completed after 4 hours, with very little additional sorption during a 20-week period. In contrast cadmium showed a continuous slight increase in the amount of adsorption over the 20-week period. Desorption experiments were conducted at pH 4.5 and similar to previous studies examining trace metal desorption from oxide surfaces, the desorption kinetics for Pb2+and Cd2+ were slow compared to the sorption reaction. None of the experiments were completely reversible after an eight-hour desorption period. For all experiments except long-term Pb2+ desorption, the quantity of metal desorbed from goethite followed the order salicylate >NaNO3 > oxalate. Based on differences in cation affinity for the iron oxide surface one would expect a greater quantity of Cd2+ to be removed compared to Pb2+, for each of the extracting solutions. However at a pH of 4.5 we did not find a statistically significant trend. We observed a difference between the amount of metal removed for short and long-term experiments in five of six experiments, but these differences were only significant for Pb2+ experiments in the presence of salicylate. Two first order rate equations best fit the kinetics of trace metals desorption, with R2 values greater than 0.910 in all cases. Although our results show a decrease in rate coefficients (expect k1 for oxalate) with increased residence time, statistical analysis indicates that these results were only significant for Pb2+ experiments in the presence of salicylate. However raw and transformed data both suggest that desorption values are diverging as a function of aging time. Similar to other researchers we believe that Pb2+ and Cd2+ are sequestered by the goethite surface with an increase in residence time. These results suggest that residence time effects observed by many researchers are much less prevalent at low pH values. Therefore a reduction in soil pH created by natural anthropogenic processes may reduce the ability of soils to naturally sequester metals over time. / Master of Science