Made available in DSpace on 2014-12-17T15:01:49Z (GMT). No. of bitstreams: 1 JanineRGV_TESE.pdf: 2247550 bytes, checksum: 088d10a559666939d74031b5c30d5017 (MD5) Previous issue date: 2010-06-17 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Seeking a greater appreciation of cheese whey was developed to process the hydrogenation of lactose for the production of lactitol, a polyol with high added value, using the catalyst Ni / activated carbon (15% and 20% nickel), the nitride Mo2N, the bimetallic carbide Ni-Mo/ activated carbon and carbide Mo2C. After synthesis, the prepared catalysts were analyzed by MEV, XRD, laser granulometry and B.E.T. The reactor used in catalytic hydrogenation of lactose was the type of bed mud with a pressure (68 atm), temperature (120 oC) and stirring speed (500 rpm) remained constant during the experiments. The system operated in batch mode for the solid and liquid and semi-continuous to gas. Besides the nature of the catalyst, we studied the influence of pH of reaction medium for Mo2C carbide as well as evaluating the character of the protein inhibitor and chloride ions on the activity of catalysts Ni (20%)/Activated Carbon and bimetallic carbide Ni-Mo/Activated Carbon. The decrease in protein levels was performed by coagulation with chitosan and adsorption of chloride ions was performed by ion exchange resins. In the process of protein adsorption and chloride ions, the maximum percentage extracted was about 74% and 79% respectively. The micrographs of the powders of Mo2C and Mo2N presented in the form of homogeneous clusters, whereas for the catalysts supported on activated carbon, microporous structure proved impregnated with small particles indicating the presence of metal. The results showed high conversion of lactose to lactitol 90% for the catalyst Ni (20%)/Activated Carbon at pH 6 and 46% for the carbide Mo2C pH 8 (after addition of NH4OH) using the commercial lactose. Monitoring the evolution of the constituents present in the reaction medium was made by liquid chromatography. A kinetic model of heterogeneous Langmuir Hinshelwood type was developed which showed that the estimated constants based catalysts promoted carbide and nitride with a certain speed the adsorption, desorption and production of lactitol / Visando, uma maior valoriza??o do soro de queijo desenvolveu-se o processamento de hidrogena??o da lactose para produ??o de lactitol, um p?liol de alto valor agregado, utilizando os catalisadores Ni/Carv?o ativado (com 15% e 20% de n?quel), o nitreto Mo2N, o carbeto Mo2C e o carbeto bimet?lico Ni-Mo/Carv?o ativado. Ap?s a s?ntese, os catalisadores preparados foram analisados por MEV, DRX, granulometria a laser e B.E.T. O reator utilizado na rea??o de hidrogena??o da lactose foi do tipo leito de lama cuja press?o (68 atm), temperatura (120 oC) e velocidade de agita??o (500 rpm) permaneceram constantes durante os experimentos. O sistema operou em batelada para a fase s?lida e l?quida e semi-cont?nuo para a fase gasosa. Al?m da natureza do catalisador, foi estudada a influ?ncia do pH do meio reacional para o carbeto Mo2C bem como a avalia??o do car?ter inibidor das prote?nas e ?ons cloretos na atividade dos catalisadores Ni(20%)/Carv?o ativo e o carbeto bimet?lico Ni- Mo/Carv?o ativo. A diminui??o dos teores de prote?nas foi realizada atrav?s da coagula??o com quitosana e a adsor??o dos ?ons cloretos foi realizada atrav?s de resinas de troca i?nica. No processo de adsor??o de prote?nas e dos ?ons cloretos, o percentual m?ximo extra?do foi em torno de 74% e 79% respectivamente. As micrografias dos p?s de Mo2C e Mo2N apresentaram-se na forma de aglomerados homog?neos, enquanto que para os catalisadores suportados em carv?o ativo, a estrutura se mostrou microporosa com pequenas part?culas impregnadas indicando a presen?a do metal. Os resultados obtidos apresentaram ?ndices de convers?o da lactose em lactitol de 90% para o catalisador Ni(20%)/Carv?o ativo em pH 6 e de 46% para o carbeto Mo2C em pH 8 (ap?s adi??o de NH4OH) utilizando a lactose comercial. O acompanhamento da evolu??o dos constituintes presentes no meio reacional foi feito por cromatografia em fase l?quida. Um modelo cin?tico heterog?neo do tipo Langmuir- Hinshelwood foi desenvolvido cujas constantes estimadas evidenciaram que os catalisadores a base de nitreto e carbeto promoveram com certa velocidade a adsor??o, produ??o e dessor??o de lactitol

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-03-20T16:46:40Z No. of bitstreams: 1 MarieleIaraSoaresDeMello_TESE.pdf: 16812894 bytes, checksum: 6e77a9036a1ea3feab8abf3d2004dd63 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-03-22T11:29:20Z (GMT) No. of bitstreams: 1 MarieleIaraSoaresDeMello_TESE.pdf: 16812894 bytes, checksum: 6e77a9036a1ea3feab8abf3d2004dd63 (MD5) / Made available in DSpace on 2018-03-22T11:29:20Z (GMT). No. of bitstreams: 1 MarieleIaraSoaresDeMello_TESE.pdf: 16812894 bytes, checksum: 6e77a9036a1ea3feab8abf3d2004dd63 (MD5) Previous issue date: 2017-03-10 / Estudos de catalisadores utilizados em rea??es para a produ??o de combust?veis alternativos, como a S?ntese de Fischer-Tropsch (SFT) e a S?ntese do Metanol via Hidrogena??o de CO2 foram realizados. O efeito da natureza qu?mica do ?xido do suporte sobre o desempenho de catalisadores de cobalto para a rea??o de Fischer-Tropsch foi investigado e uma s?rie de suportes foram sintetizados por meio de uma cobertura em monocamada da ?-Al2O3 com v?rios ?xidos representativos de uma ampla gama de car?ter ?cido-b?sico de Lewis, os quais foram caracterizados por espectroscopia de UV-Vis acoplado com adsor??o de alizarina. Foi poss?vel preparar catalisadores modelos com tamanho de part?culas de Co e porosidades semelhantes, possibilitando o estudo do efeito do suporte, sem sobreposi??o de fatores de difus?o ou tamanho de part?cula. A seletividade de hidrocarbonetos C13+ mostrou depend?ncia do tipo Volcano, com um m?ximo em um car?ter ?cido-base intermedi?rio. A localiza??o das nanopart?culas (NPs) das fases ativas no interior dos canais mesoporosos e o efeito de promo??o do ZrO2 nas propriedades e no desempenho catal?tico dos catalisadores na S?ntese de Metanol via Hidrogena??o de CO2 foi estudado. Tr?s m?todos de co-precipita??o foram empregados para estudar a inser??o das NPs no interior dos mesoporos do suporte. Os m?todos utilizados, ao contr?rio do m?todo de impregna??o a volume de poro convencional, se mostraram como uma forma simples e eficaz de localizar as nanopart?culas de Cu e dos promotores ZnO e ZrO2 nos mesoporos do suporte SBA-15, bem como um efeito positivo nos catalisadores com a incorpora??o do promotor ZrO2. De forma geral, a incorpora??o de ZrO2 mostrou-se eficaz na melhoria da dispers?o e localiza??o das nanopart?culas de Cu e, portanto, maior grau de intera??o do Cu0 com os promotores ZnO e ZrO2. Efeitos de localiza??o e de promo??o do ZrO2 contribuem para a produ??o de catalisadores mais ativos e seletivos para esta rea??o. / Several studies of catalysts used in reactions for the production of energy fuels, such as Fischer-Tropsch Synthesis (FTS) and Methanol Synthesis from CO2 were done. The chemical nature effect of the oxide support on the performance of Cobalt Fischer?Tropsch catalysts was investigated. A series of supports were synthesized via monolayer coverage of porous ?-Al2O3 with various representative oxides from a wide range of Lewis acid?base character, which were characterized by UV?VIS spectroscopy coupled to alizarin adsorption. It was possible to obtain model catalysts with Co particle size and porosity alike, allowing to study the effect of the support without overlapping diffusion factors or particle size. C13+ hydrocarbon selectivity showed volcano-type dependence, with a maximum of intermediate acid-base character. The the nanoparticles of Cu/ZnO/ZnO2 confinement and the promoter effect on the properties and ZrO2 was studied in the context of the catalysts performance in Methanol synthesis via Hydrogenation of CO2. Three co-precipitation methods were chosen to study the nanoparticles confinement in the mesopores. The methods used, unlike the conventional pore volume impregnation method, showed a simple and effective way to confine the Cu/ZnO/ZrO2 NPs in the mesopores of the supporting SBA-15, as well as a positive effect in catalytic converters with the ZrO2 promoter incorporation. In general, the ZrO2 incorporation was effective in improving the dispersion and confinement of Cu NPs and, therefore, a greater Cu0 interaction with ZnO and ZrO2 promoters. Effects of confinement and promotion contributed to the production of more active and selective catalysts for this reaction.