CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O Biodiesel à industrialmente produzido atravÃs de reaÃÃo homogÃnea de transesterificaÃÃo de Ãleos vegetais na presenÃa de espÃcies bÃsicas como catalisadores. Entretanto, neste processo hà a necessidade de purificaÃÃo da fase Ãster e remoÃÃo da base apÃs a reaÃÃo. Neste trabalho, diferentes catalisadores bÃsicos heterogÃneos, tais como Ãxido de cÃlcio (4-20%) suportado sobre a sÃlica mesoporosa SBA-15 e catalisadores de Ãxidos MgAl e MgCa com diferentes relaÃÃes molares (3-24) Mg/Ca e Mg/Al, foram sintetizados e avaliados em reaÃÃes de transesterificaÃÃo. As propriedades texturais e a caracterizaÃÃo estrutural dos catalisadores foram determinadas pelas tÃcnicas de DRX, XPS, FT-IR, MEV e adsorÃÃo- dessorÃÃo de N2 a -196ÂC. A basicidade foi estudada mediante tÃcnicas de TPD-CO2 e decomposiÃÃo de isopropanol. A atividade catalÃtica foi avaliada em reaÃÃes de transesterificaÃÃo do butirato de etila com metanol, algumas variÃveis da reaÃÃo foram otimizadas e o catalisador mais ativo foi testado na produÃÃo de biodiesel a partir dos Ãleos de mamona e girassol. Para a sÃrie de catalisadores mesoporosos, a amostra com 14% de CaO em SBA-15 foi o catalisador mais ativo na transesterificaÃÃo do butirato de etila com metanol a 60ÂC e pressÃo atmosfÃrica. A maior atividade na produÃÃo de biodiesel foi observada para o catalisador SBA15-14CaO apresentando valores de conversÃo de 65,7% e 95% para os Ãleos de mamona e girassol apÃs 1 e 5h de tempo de reaÃÃo, respectivamente. Para os catalisadores de Ãxidos MgAl e MgCa, os catalisadores de MgCa mostraram-se mais ativos que os MgAl para a transesterificaÃÃo do butirato de etila. Em reaÃÃo com Ãleo de girassol, foi observado para o catalisador MgCa3 uma conversÃo de 92% a uma relaÃÃo molar metanol:Ãleo de 12, temperatura de reaÃÃo de 60ÂC e 2,5% em peso de catalisador no meio reacional. / Biodiesel is industrially produced by homogeneous transesterification of vegetable oils in the presence of basic species. However, removal of the base after reaction is a major problem, since purification of the ester phase is needed. In this study, different heterogeneous catalysts, based on calcium oxide (4-20%) supported on mesoporous SBA- 15 silica, and MgAl and MgCa oxides with different Mg/Ca and Mg/Al molar ratios (3- 24), have been synthesized, characterized and evaluated in transesterification reactions. Their textural and structural characterizations were carried out using XRD, XPS, FT-IR, SEM and N2 sorption at -196ÂC. Their basicities were studied by CO2-TPD and isopropanol catalytic decomposition. Their catalytic activities was evaluated for the transesterification reaction of ethyl butyrate with methanol, and several reaction parameters were optimized. The most active catalysts were tested in biodiesel production from castor and sunflower oils. The sample with a 14 wt% of CaO in SBA-15 was the most active catalysts in the transesterification of ethyl butyrate with methanol at 60ÂC and atmospheric pressure. For the MgAl and MgCa oxide catalysts, MgCa mixed oxides were more active than MgAl in the same system. The highest activity in biodiesel production was found for SBA15-14CaO as 65,7% and 95% for castor and sunflower oils after reacting for 1 and 5h, respectively. In the case of MgAl and MgCa oxides catalysts, sunflower oil conversion of 92% was achieved with methanol:oil molar ratio of 12, reaction temperature of 333 K and 2.5 wt% of MgCa3 catalyst. ______________________________________________________________________

O verniz acrílico Paraloid B72TM é um termoplástico que atua como um bom adesivo formando filmes claros. Tem sido usado em conservação e restauração de bens culturais desde os anos 50. Por apresentar Tg próximo a 40°C, no Brasil, algumas substâncias podem ficar adsorvidas à superfície de camadas pictóricas envernizadas. Nesse caso, a limpeza tradicional (palito com algodão e solventes) pode acarretar danos (penetração do solvente, abrasão, etc.) à obra de arte. A limpeza por métodos aquosos (géis e emulsões) pode deixar resíduos que interagem com os materiais originais. Por outro lado, a utilização de nano-géis magnéticos é bastante restrita e de difícil acesso. Esse trabalho tem por objetivo o desenvolvimento de filmes adsorventes de celulose/SBA-15 para retirada do verniz Paraloid B72TM, onde se fizer necessário. Esses filmes foram empregados sobre miméticos (pinturas originais de diferentes técnicas e obras confeccionadas para estudo envernizadas com Paraloid B72TM) para verificação de sua eficácia. As matérias primas, os miméticos e os filmes adsorventes, antes e após a aplicação, foram caracterizadas por técnicas físico-química e analíticas [análise térmica (TG/DTG e DTA); espectroscopia no infravermelho (FTIR); microscopia eletrônica de varredura (MEV); microscopia eletrônica de transmissão (MET); espectroscopia de fluorescência de raios X (XRF), microscopia digital de superfície e estereoscopia]. A microscopia digital de superfície e a estereoscopia foram usadas para inspeção do micro morfologia da superfície e possibilitaram identificar a presença de partículas adsorvidas na superfície das obras. A MEV, a MET permitiram observar a micromorfologia das superfícies e a FTIR caracterizar as matérias primas e os filmes adsorventes. O comportamento térmico das matérias primas e dos filmes adsorventes, antes e após a aplicação, foi avaliado por TG/DTG e DTA. A avaliação dos miméticos e dos filmes de adsorção, antes e depois da aplicação, por XRF evidenciou que não houve danos aos miméticos. O filme de celulose/SBA-15 como adsorvedor da resina acrílica na limpeza de superfícies policromadas em obras de arte, por meio de um solvente, se mostrou eficaz. Esse método é alternativo e não pretende substituir qualquer outro já existente. Visto que, em restauração de obras de arte cada caso é especifico e nada substitui o conhecimento, discernimento e destreza do restaurador. / The acrylic varnish Paraloid B72TM is a thermoplastic, which acts as an adhesive forming clear films. It has been used in conservation and restoration of cultural property since the 50ths. By presenting Tg near 40°C, some substances can become adsorbed on the surface of varnished paintng layers, for example in Brazil. In this case, the traditional cleaning (stick with cotton and solvents) can cause damage (penetration of the solvent, abrasion,...) to the artwork. The cleaning of aqueous methods (gels and emulsions) can leave residues that interact with the original materials. Already, the use of magnetic nano-gels is restricted and difficult to access. This paper aims at developing cellulose/SBA-15 adsorbent films for withdrawal of Paraloid B72TM varnish, where it becomes necessary. These films were employed on mimetic (original paintings of different techniques and works made for study varnished with Paraloid B72TM) to verify its effectiveness. The raw materials, adsorbents and mimetic films before and after application were characterized by physico-chemical and analytical techniques [thermal analysis (TG/DTG and DTA); infrared spectroscopy (FTIR); scanning electron microscopy (SEM); transmited electron microscopy (TEM); fluorescent X-ray spectroscopy (XRF), digital microscopy and surface stereoscopic]. The digital microscopy and surface stereoscopy were used to inspect the surface micro morphology and it was possible to identify the presence of particles adsorbed on the surface of the artwork. The SEM, the TEM showed the micro morphology of the surfaces and FTIR characterized the raw materials and adsorbents films. The thermal behavior of materials and adsorbents films before and after application was evaluated by TG/DTG and DTA. Assessment of adsorption and mimetics films before and after application by XRF showed that there was no damage to the mimetic. The cellulose/SBA-15 film as adsorbent in the acrylic resin in polychrome surface cleaning artwork by means of a solvent, is effective. This method is alternative and not intended to replace any existing one. Since, in restoration of works of art each case is specific and nothing replaces the knowledge, insight and conservator dexterity.

L’influence de paramètres de synthèse et de traitements post-synthèse sur le caractère hydrophobe/hydrophile de silices mésoporeuses organisées (SMO) de type SBA-15 a été étudiée. Ainsi nous avons montré que la durée du mûrissement peut être réduite à la durée nécessaire à la précipitation. La température, l’agitation et la durée de synthèse modulent la morphologie des particules et des agrégats. Le mode de chauffage, la présence d’un sel inorganique et le rapport silice/tensioactif ont un effet sur la structure et la texture du matériau. Concernant les traitements post-synthèse, nous avons considéré l’élimination de l’agent structurant et la fonctionnalisation par greffage. Le taux de silanols diminue suite au vieillissement mais surtout après calcination : cette étape efface les différences en termes de teneur en silanols. C’est la raison pour laquelle une nouvelle méthode d’élimination du tensioactif efficace (dès 300 °C) et rapide (dès 15 min) a été mise en œuvre : la calcination à l’aide d’un four à induction conduit à un matériau avec des propriétés structurales, texturales et une teneur en silanols supérieures à celles d’une SMO de type SBA-15 calcinée par la méthode conventionnelle. La calcination par induction a également été appliquée avec succès sur différents types de SMO telles que la SBA-16 et la MCM-41. Ensuite, l’influence des caractéristiques initiales de la SMO sur la fonctionnalisation par un greffage post-synthèse a été étudiée. Une SMO de type SBA-15 plus hydrophobe a été obtenue avec un greffon possédant une seule fonction condensable. La teneur initiale et probablement l’accessibilité des silanols ont un impact significatif sur le taux de greffage. / The influence of synthesis parameters and post-synthesis treatments on the hydrophobic/hydrophilic character of SBA-15 type ordered mesoporous silicas (OMS) was studied. It was found that the duration of ripening can be reduced to the precipitation time. Temperature, stirring and duration of synthesis steps can modulate the morphology of particles and aggregates. Heating process, presence of an inorganic salt and silica/surfactant ratio are also parameters that affect the structure and texture of the material. Concerning post-synthesis treatments, the elimination of the template and the functionalization by grafting were considered. The rate of silanols decreases during aging but mostly after calcination: this step erases the differences in silanol content. This is why a new method for an effective (at 300 ° C) and fast (for 15 min) removal of the surfactant has been implemented: the calcination using an induction furnace leads to a material with structural, textural properties and silanol content greater than those of a SBA-15 material calcined by the conventional method. The calcination induction has also been successfully applied on different types of OMS such as SBA-16 and MCM-41. Then, the influence of the OMS characteristics on functionalization by post-synthesis grafting was studied. The more hydrophobic SBA-15 material was obtained with a grafting agent possessing a single condensable function. It was also observed that the initial content and the accessibility of silanols probably have a significant impact on the grafting rate.

A visão de muitas pessoas sobre uma colônia de formigas, em geral, é de que estes pequenos e inofensivos insetos somente se movem aleatoriamente para coletar alimento e conservá-los em seus ninhos. Um olhar destreinado não conseguiria notar o nível de complexidade e organização que é requerido por uma colônia de formigas para sua sobrevivência. Uma formiga simples é parte de um grande grupo que coopera entre si para criar um superorganismo. Sem uma autoridade central ou indivíduos com habilidade de um pensamento cognitivo complexo, a colônia se auto-organiza, e, de fato, ajusta seus recursos de uma maneira muito eficiente. Essa dissertação investiga o papel da comunicação indireta nas tarefas de exploração e forrageamento, e como isso afeta as decisões de um agente simples e traz um comportamento emergente útil à toda colônia. Por fim, este trabalho implementa uma plataforma de simulação multi-agente inspirado em formigas / Most people\'s view of an ant colony and ants in general is that they simply pose harmless little insects that move randomly and gather food in their underground nests. The untrained eye would have never guessed the level of complexity and organisation that is required in order for an ant colony to survive. The simple ant is a part of a huge group, which cooperate one superorganism. Without any central authority or the ability of complex cognitive thought from the individuals, the colony seems to self organise and in fact adjust its resources in a quite efficient way. This dissertation investigates the role of indirect communication in the exploration and forage task and how it affects the decisions of the single agent and brings an emergent behaviour that is useful to all the colony. Finally this work implements an ant inspired multi-agent simulation plataform

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2018-04-04T13:50:36Z No. of bitstreams: 1 2017 - Guilherme Raymundo Sa.pdf: 3173899 bytes, checksum: 9c3276f740106907243c1c187bbc9d77 (MD5) / Made available in DSpace on 2018-04-04T13:50:36Z (GMT). No. of bitstreams: 1 2017 - Guilherme Raymundo Sa.pdf: 3173899 bytes, checksum: 9c3276f740106907243c1c187bbc9d77 (MD5) Previous issue date: 2017-08-28 / Zeolites are microporous aluminosilicates and have assumed the position of most important catalysts in the chemical industry. However, these microporous materials have the limitation of the diffusion of molecules with larger kinetic diameter. Hybrid materials with hierarchical arrangement of pores in the micro-mesoporous scale have attracted great attention and interest in the last decades because they present acidic activity similar to the microporous zeolites and ordered pore diameter of the mesoporous materials. Beta zeolite can be used in a number of applications, including refining, petrochemical and biomass. The generation of mesopores in the beta zeolite enables higher yields by improving mass transfer in the FCC process. In this work, samples of the mesoporous material SBA-15 were synthesized and used as a source of silica for the synthesis of the mesoporous beta zeolite using the Dry Gel Conversion (DGC) technique. Samples of SBA-15 were submitted to three carbonization methods, using as carbon source sucrose, the organic template and both, in order to fill their pores with carbonaceous material and to prevent the collapse of its structure. The aluminization samples were studied at two times, before and during the dry gel synthesis. Three crystallization times were studied. X-ray diffraction (XRD), N2 adsorption / desorption, nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) and infrared absorption spectroscopy with Fourier transform (FTIR) were used to characterize the samples. The results indicated that there was formation of zeolite beta presenting mesoporosity for the carbonization method that used only the template as carbon source. These samples showed BEA crystalline structure confirmed by XRD and FTIR analysis and formation of isotherms with type I and IV characteristics, with BET area greater than 500 m? / g, a volume of micropores close to 0.20 cm3 / g and with a volume of mesopores greater than 0.15 cm 3 / g. The other carbonization methods formed an amorphous phase, materials with low crystallinity and formation of polymorphs B and C over polymorph A. The samples presented the formation of mesoporosity did not present the mesopores present in the SBA-15, indicating collapse of the structure during the process of dry gel conversion / Ze?litas s?o aluminossilicatos microporosos e assumiram a posi??o de catalisadores mais importantes na ind?stria qu?mica. Entretanto, esses materiais microporosos possuem a limita??o da difus?o de mol?culas com di?metro cin?tico maior. Os materiais h?bridos com arranjo hier?rquico de poros na escala micro-mesoporosa atra?ram grande aten??o e interesses nas ?ltimas d?cadas pois apresentam atividade ?cida similar ?s ze?litas microporosas e di?metro de poros ordenados dos materiais mesoporosos. A ze?lita Beta pode ser usada em diversas aplica??es, incluindo o refino, a petroqu?mica e o processamento de biomassa. A gera??o de mesoporos na ze?lita beta possibilita maior rendimento melhorando a transfer?ncia de massa no processo de FCC. Neste trabalho foram sintetizadas amostras do material mesoporoso SBA-15 e utilizadas como fonte de s?lica para a s?ntese da ze?lita beta mesoporosa em meio seco utilizando a t?cnica de Dry Gel Conversion (DGC). As amostras de SBA-15 foram submetidas a tr?s m?todos de carboniza??o, utilizando como fonte de carbono sacarose, o direcionador de estrutura e ambos, com o objetivo de preencher seus poros com material carbon?ceo e evitar o colapso de sua estrutura. A aluminiza??o das amostras foi estudada em dois momentos, antes e durante a s?ntese do gel seco. Foram estudados tr?s tempos de cristaliza??o. Para caracteriza??o das amostras foram utilizadas as t?cnicas de difra??o de raios-X (DRX), adsor??o/dessor??o de N2, resson?ncia magn?tica nuclear (RMN), microscopia eletr?nica de varredura (MEV) e espectroscopia de absor??o no infra vermelho com transformada de Fourier (FTIR). Os resultados indicaram que houve a forma??o de ze?lita beta apresentando mesoporosidade para o m?todo de carboniza??o que utilizou apenas o direcionador de estrutura como fonte de carbono. Estas amostras apresentaram estrutura cristalina BEA confirmado pelas an?lises de DRX e FTIR e forma??o de isotermas com caracter?sticas do tipo I e IV, com ?rea BET superior a 500m?/g, um volume de microporos pr?ximos de 0,20 cm3/g e com um volume de mesoporos superior a 0,15 cm3/g. Os demais m?todos de carboniza??o formaram uma fase amorfa, materiais de baixa cristalinidade e com forma??o dos polimorfos B e C em detrimento ao polimorfo A. Os melhores resultados foram obtidos com o tempo de cristaliza??o de 48 horas. As amostras apresentando a forma??o de mesoporosidade n?o apresentaram os mes n?o apresentaram os mes n?o apresentaram os mesn?o apresentaram os mes n?o apresentaram os mesn?o apresentaram os mes n?o apresentaram os mes n?o apresentaram os mesn?o apresentaram os mes n?o apresentaram os mes n?o apresentaram os mes oporos presentes na SBA oporos presentes na SBA oporos presentes na SBA oporos presentes na SBA oporos presentes na SBA oporos presentes na SBA oporos presentes na SBAoporos presentes na SBAoporos presentes na SBAoporos presentes na SBA-15, indicando colapso da 15, indicando colapso da 15, indicando colapso da 15, indicando colapso da 15, indicando colapso da 15, indicando colapso da 15, indicando colapso da 15, indicando colapso da 15, indicando colapso da estrutura estrutura estrutura durante o processo de s?ntese seca

The total amount of plastic wastes produced by our society has been growing rapidly. The low biodegradability of these wastes creates a serious environmental problem that is directing the governments and environmental agencies to take serious measures to solve the problem of the plastic wastes. Landfilling or incineration of these wastes are not the right solutions, because the former has the danger of leaching and soil impregnation of its degradation products and the latter produce air pollution problems due to the possible emissions of toxic and acid gases. An alternative approach to the solution of problem caused by these wastes is the recycling of them by chemical recovery. In this method, the waste plastics are thermally non-catalytically or catalytically degraded into gases and oils. In this study, pure and aluminum containing ordered mesoporous materials MCM-type and SBA-type, were synthesized using different aluminum sources and aluminum loadings in order to be tested in catalytic degradation of polypropylene. These catalysts, except aluminum containing SBA-type catalysts, were synthesized by hydrothermal synthesis method. Aluminum containing SBA-type catalysts were synthesized by impregnation method. Tetraethyl orthosilicate was used as the Si source and aluminum nitrate, aluminum sulphate and aluminum isopropoxide were used as the Al source. It was observed that these materials had high surface areas and exhibited Type IV isotherms. In MCM-type materials, the aluminum incorporated more effectively into the structure at low concentrations but not effectively at high concentrations. On the other hand, in SBA-type catalysts, the aluminum incorporation into structure was very effective. 27Al MAS NMR spectra of the catalysts exhibited a mixture of tetrahedral and octahedral aluminum. TEM images showed well-ordered hexagonal arrays of mesopores. As an initial step, the activation energy value of polypropylene pyrolysis reaction in the presence of synthesized catalysts was determined by the help of a thermal analyzer and these TGA results showed a marked reduction in the degradation temperature. In the case of using aluminum containing MCM-type materials, the activation energy values decreased to about 68-126 kJ/mol. On the other hand, when aluminum containing SBA-type catalysts were used, the activation energy values decreased from 172 kJ/mol to a value in the range of 51 &ndash / 89 kJ/mol. Heavier molecules degraded into lighter hydrocarbons in the presence of catalysts and they gave high ethylene selectivity among the gaseous products. Additionally, butane selectivity increased with the use of catalysts. SBA-type catalysts showed higher selectivity to lighter hydrocarbons (&lt / C14). C7 selectivity among the liquid products was high when aluminum isopropoxide was used in the synthesis of catalysts and C18 selectivity increased significantly when aluminum nitrate was used in the synthesis of MCM-type catalysts.

La synthèse tout-en-un de 4-quinolones et d'indoxyles a été réalisée par couplage de Sonogashira carbonylant suivi d'une cyclisation. Une étude en catalyse homogène a révélé que les catalyseurs présents contrôlaient la sélectivité vers l'un ou l'autre des composés. Si la première étape est pallado-catalysée, l'étape de cyclisation est catalysée par des nucléophiles organiques. Ainsi, des 4-quinolones ont été préparées par multi-catalyse {[Pd]+amine} et des indoxyles par catalyse tandem {[Pd]/phosphine}. Les systèmes catalytiques ont été hétérogénéisés par fonctionnalisation de silices mésoporeuses de type SBA. Deux stratégies ont été utilisées pour contrôler la localisation de la fonctionnalité. Différents complexes de Pd ont été intégrés dans les pores du matériau par greffage post-synthétique ou dans les murs par synthèse directe. Plusieurs amines et une phosphine ont été immobilisées par greffage post-synthétique donnant ainsi des catalyseurs nucléophiles fonctionnalisés dans leurs pores. Les activités catalytiques de ces matériaux ont été évaluées dans la synthèse de la 2-phényl-4-quinolone et du 2-benzylidène-indoxyle. La première a été préparée dans de bons rendements et le système {[Pd]@SBA+amine@SBA} est recyclable sur 3 cycles. Tous les matériaux ont montré une lixiviation du Pd mais leur utilisation permet de diminuer la contamination en Pd du produit final comparé à un complexe homogène. L'indoxyle a été obtenu avec un système semi-hétérogène {[Pd]@SBA/PPh3}, l'utilisation de la phosphine greffée conduisant à la transformation de l'indoxyle vers le 2-benzylindole. La formation d'α-céto-amides en catalyse hétérogène via double carbonylation a aussi été étudiée

Catalysis is an important field of study in chemical engineering and chemistry due to its application in a vast number of chemical transformations. Traditionally, catalysts have been developed as homogeneous molecular species or as heterogeneous insoluble materials. While homogeneous catalysts are typically very active and selective, they are difficult to recover. Conversely, heterogeneous catalysts are easy to recover and reuse, but they generally are less selective. To address these issues, the immobilization of homogeneous catalyst analogs onto solid supports has been a subject of research for the past few decades. Nonetheless, the effects of immobilization are still not completely predictable, and so continued effort is required to develop new immobilized catalysts as well as to develop a better understanding of how different parameters affect catalytic behavior. This dissertation presents the synthesis, characterization, and evaluation of new immobilized catalysts for different applications. First, a solid base catalyst supported on silica was developed and studied in the synthesis of cyclic carbonates from epoxides and carbon dioxide. Next, polymer and silica supported vanadium Schiff base catalysts were developed and evaluated for use in the oxidative kinetic resolution of alpha-hydroxy esters, an enantioselective reaction. Lastly, salen catalyst analogs with amine reactive functional groups were synthesized and characterized for grafting onto aminosilicas with different degrees of amine group isolation. The grafted catalysts were then tested to determine how catalyst spacing on the surface affects their behavior. Throughout the presentation of these results, comparisons are made amongst the new supported catalysts and relevant existing catalysts to discern general trends which could be applied to a wider range of immobilized catalysts. Finally, research opportunities for further improvements in these areas are suggested.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-09-19T19:40:39Z No. of bitstreams: 1 CassiaCarvalhoDeAlmeida_TESE.pdf: 6857436 bytes, checksum: 5d930402b569e88da7eb76c2ad9e091d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-09-19T22:52:56Z (GMT) No. of bitstreams: 1 CassiaCarvalhoDeAlmeida_TESE.pdf: 6857436 bytes, checksum: 5d930402b569e88da7eb76c2ad9e091d (MD5) / Made available in DSpace on 2017-09-19T22:52:56Z (GMT). No. of bitstreams: 1 CassiaCarvalhoDeAlmeida_TESE.pdf: 6857436 bytes, checksum: 5d930402b569e88da7eb76c2ad9e091d (MD5) Previous issue date: 2017-05-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Nos ?ltimos anos os processos de reforma para a produ??o de hidrog?nio como um vetor energ?tico vem sendo bastante estudados, em fun??o do aumento da demanda por tecnologias alternativas de gera??o de energia, apresentando uma boa rela??o custo/benef?cio quando comparados a outras tecnologias de produ??o de hidrog?nio. Al?m disso, possuem vantagens do ponto de vista ambiental, n?o contribuindo com o aumento da concentra??o de CO2 na atmosfera. No entanto, a produ??o de hidrog?nio atrav?s dos processos de reforma, embora promissora, ainda apresenta muitos gargalos tecnol?gicos, necessitando de avan?os em novos materiais com propriedades catal?ticas. Dentro desta proposta, este trabalho teve como objetivo obter materiais catal?ticos com alta reatividade e seletividade para produtos frente ?s rea??es de reforma a vapor do etanol (RVE) e reforma a seco do metano (RSM). Desta maneira, catalisadores a base de n?quel e cobalto suportado em SBA-15 foram preparados pelo m?todo de impregna??o via ?mida e caracterizados antes e ap?s os testes catal?ticos, pelas t?cnicas: An?lise Termogravim?trica (TGA), Espectroscopia na Regi?o do Infravermelho (IR), Difra??o de Raios X (DRX), An?lise de Redu??o ? Temperatura Programada (RTP), Adsor??o e Dessor??o de Nitrog?nio, Difra??o de Raios X in situ (DRX in situ) e Microscopia Eletr?nica por Varredura (MEV) com Espectroscopia de Energia Dispersiva (EDS), visando ? compreens?o dos mecanismos envolvidos nas rea??es de reforma e tamb?m respons?veis pela deposi??o de carbono sobre os catalisadores. Os catalisadores testados frente ? rea??o a vapor do etanol durante 6 horas a 500 ?C apresentaram convers?o inicial em torno de 80-100 %, com produ??o de H2 (60-70 %), CO2 (18-23 %) e com apenas tra?os de CO (0,5-10 %). No entanto, estes catalisadores sofreram r?pida desativa??o nas primeiras horas de teste, sendo mais promissores frente ? rea??o de reforma a seco do metano, os quais apresentaram boa atividade catal?tica e estabilidade durante 10 horas de rea??o a 700 ?C, com convers?es (CH4 e CO2) e rendimentos a H2 acima de 80 % e baixa deposi??o de carbono. / In the last years, the processes of reform for the production of hydrogen as an energetic vector have been well studied because of the increase of the demand for alternative technologies of energy generation, showing a good relation cost/benefit when compared to other technologies of hydrogen production. In addition, they have advantages from an environmental point of view, not contributing to the increase of CO2 concentration in the atmosphere. However, hydrogen production through reform processes, while promising, still presents many technological bottlenecks, requiring advances in new materials with catalytic properties. In this proposal, the goal of this work is to obtain catalytic materials with high reactivity and selectivity for products in the face of reactions of steam reforming of ethanol (SRE) and dry reforming of methane (DRM). Catalysts based on nickel and cobalt supported on SBA-15 were prepared by wet impregnation method and characterized before and after the catalytic tests by several techniques: Thermogravimetric Analysis (TGA), Fourier Transformer Infrared Spectroscopy (FT- IR), X-ray diffraction (XRD), Temperature Programmed Reduction (TPR), Nitrogen Adsorption and Desorption, X-ray Diffraction in situ (XRD in situ), and Scanning Electron Microscopy (SEM) with Energy Spectroscopy (ES) to understanding the mechanisms involved in the reforming reactions and also responsible for the deposition of carbon on the catalysts. The catalysts tested against the steam reaction of ethanol for 6 hours at 500 ?C presented an initial conversion around 80-100 %, with H2 (60-70 %), CO2 (18-23 %) and only traces of CO (0.5-10 %), but they suffered a rapid deactivation in the first hours of test, being more promising in the dry reforming reaction of methane, which showed good activity and stability during 10 hours of reaction at 700 ?C with conversions (CH4 and CO2) and H2 yields above 80 % and low carbon deposition.

Made available in DSpace on 2015-05-14T13:21:26Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1985017 bytes, checksum: d2b42e6316873e9c73d1d84ea20f59d2 (MD5) Previous issue date: 2012-12-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work reports the synthesis of the SBA-15 mesoporous silica the acidic hydrolisis of the tetraethylortosilicate (TEOS), and using the P123 pluronic copolymer (EO20PO70EO20). The precursor matrix was organically modified by silanization with the 3- trimethoxypropylsilyldiethylenetriamine, named as SBA-15-3N. The solids were characterized by low angle X-ray diffraction, CHN elemental analysis, N2 adsorption/dessorption measurements, absorption infrared spectroscopy, 29Si and 13C solid state nuclear magnetic resonance, scanning electron microscopy and transmission electron microscopy. Elemental analysis data indicated the amount of 1.53 mmol of nitrogen per gram of silica, which was confirmed by the infrared spectra. 29Si NMR showed the prevalence of T2 and T3 species in the solid SBA-15-3N. These data demonstrated the efficiency of the organofunctionalization of the SBA-15. The measurements of zeta potential showed that the SBA-15-3N has null surface charge at pH 9.2, favoring the adsorption of anionic dyes in a wide pH range. Finally, the SBA-15-3N was applied in the retention of the anionic dyes RN remazol blue and RG remazol yellow, using a factorial design to evaluate the agitation time, temperature and pH. The results showed that the SBA 15-3N was an efficient adsorbent for removing of the reactive dyes from aqueous solution. The use of experimental design was important to establish the optimized conditions, where the maximum retention capacities were 514 and 370 mg/g for RN remazol blue and RG remazol yellow, respectively, and both processes were fitted to Langmuir modified adsorption model. / Neste trabalho, foi realizada a síntese da sílica SBA-15 pela hidrólise ácida do tetraetilortossilicato (TEOS) utilizando o copolímero plurônico P123 (EO20PO70EO20). A matriz precursora foi modificada organicamente por silanização com 3- trimetoxipropilsilildietilenotriamino, sendo denominada SBA-15-3N. Os sólidos foram caracterizados através das técnicas de difratometria de raios-X a baixo ângulo, análise elementar de CHN, medidas de adsorção/dessorção de nitrogênio, espectroscopia na região do infravermelho, ressonância magnética nuclear no estado sólido de 29Si e 13C e microscopias eletrônicas de varredura e transmissão. A análise elementar indicou o ancoramento de 1,53 mmol de nitrogênio por grama de sílica, cuja presença foi confirmada nos espectros de infravermelho. Os dados de RMN de 29Si indicaram a prevalência de grupos T2 e T3 na amostra SBA-15-3N, e demonstraram a eficiência da funcionalização da sílica SBA-15. O estudo do potencial zeta mostrou que a SBA-15-3N apresenta carga superficial igual a zero em pH de 9,2, favorecendo a adsorção de corantes aniônicos em uma ampla faixa de pH. Finalmente, a matriz SBA-15-3N foi aplicada na retenção dos corantes reativos aniônicos azul de remazol RN e amarelo de remazol RG, utilizando um planejamento fatorial, para avaliar os efeitos dos fatores tempo de contato, temperatura e pH. Os resultados mostraram que a SBA-15-3N foi um adsorvente eficiente para a remoção de corantes reativos em solução aquosa. O uso do planejamento fatorial foi importante para estabelecer as condições experimentais otimizadas de adsorção, nas quais a capacidade máxima de retenção foi de 514 e de 370 mg/g para os corantes azul de remazol RN e amarelo de remazol RG, respectivamente, sendo que ambos os processos se ajustaram ao modelo de adsorção de Langmuir.