Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-26T23:16:09Z No. of bitstreams: 1 MonickarlaTeixeiraPegadoDaSilva_DISSERT.pdf: 2972749 bytes, checksum: 333ef217ee5461818b38fff8de7cfdeb (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-31T00:12:48Z (GMT) No. of bitstreams: 1 MonickarlaTeixeiraPegadoDaSilva_DISSERT.pdf: 2972749 bytes, checksum: 333ef217ee5461818b38fff8de7cfdeb (MD5) / Made available in DSpace on 2016-08-31T00:12:48Z (GMT). No. of bitstreams: 1 MonickarlaTeixeiraPegadoDaSilva_DISSERT.pdf: 2972749 bytes, checksum: 333ef217ee5461818b38fff8de7cfdeb (MD5) Previous issue date: 2016-02-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Suportes catal?ticos ? base de ?xido de alum?nio foram sintetizados pelo m?todo e esferas h?bridas utilizando carboximetilcelulose (CMC) como precursor org?nico (template) e nitrato de alum?nio como precursor inorg?nico. As caracteriza??es foram realizadas por an?lises de termogravimetria (TG), difra??o de raios-X (DRX), espectroscopia no infravermelho por transformada de fourier (FTIR), microscopia eletr?nica de varredura (MEV) e fisissor??o N2. Os materiais sintetizados foram testados na rea??o de convers?o do glicerol em fase g?s. Os estudos da s?ntese indicaram que as caracter?sticas do biopol?mero (grau de substitui??o e de polimeriza??o) influenciam diretamente no valor m?ximo da rela??o entre o precursor org?nico e inorg?nico para a forma??o das esferas h?bridas. As propriedades f?sico-qu?micas do material final (cristalinidade, porosidade, ?rea espec?fica e morfologia) mostraram uma depend?ncia direta com as propriedades do biopol?mero (grau de substitui??o e de polimeriza??o), indicando a versatilidade desta rota s?ntese. Os espectros de FTIR confirmaram a forma??o de um material h?brido quando se compara o espectro da CMC pura com os s?lidos obtidos ap?s a secagem. Os resultados de DRX mostraram um perfil de material amorfo para algumas amostras. Para alguns s?lidos foi poss?vel identificar a forma??o de uma fase cristalina relacionada com a alumina hidratada, ?xido de alum?nio e ?xido de cobre. As imagens obtidas por MEV indicaram a forma??o de um material com morfologia semelhante a uma esponja ap?s a calcina??o, caracter?stico de um s?lido altamente poroso. O perfil de adsor??o/dessor??o de N2 confirma a forma??o de materiais contendo micro-mesoporos com uma ?rea espec?fica entre 50-162 m2.g-1 para os suportes e 112-303 m2.g-1 para os catalisadores com cobre, indicando um aumento ?rea ap?s a adi??o do Cu por impregna??o devido a redissolu??o e recristaliza??o da fase alumina. Testes catal?ticos indicaram que os ?xidos s?o ativos e seletivos para a convers?o do glicerol (92-15%) a bioprodutos de alto maior valor agregado, confirmando a viabilidade do m?todo de s?ntese. / Catalytic supports based on aluminum oxide were synthesized by the method of hybrid spheres using carboxymethylcellulose (CMC) as organic precursor (template) and aluminum nitrate as inorganic precursor. The characterizations were performed by thermal chemical analysis (TGA), X-Ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and N2 physisorption. The study of synthesis indicated that the characteristics of the biopolymer (degree of substitution and polymerization) directly influence on the maximum value of the ratio between the organic and inorganic precursor for the formation of hybrid spheres. The physicochemical properties of the final material (crystallinity, porosity, surface area and morphology) showed a direct dependence on the biopolymer properties (degree of substitution and polymerization), indicating the versatility of this synthesis route. The FTIR spectra confirm the formation of a hybrid material when comparing the pure CMC spectrum with the obtained solids after drying. The XRD results show a profile of amorphous and crystalline material for the different samples. For some solids were possible to identify the formation of a crystalline phase related to the hydrated alumina, aluminium oxide and copper oxide. The images obtained by SEM analysis showed the formation of a material with sponge-like morphology after calcination, characteristic of highly porous solid. The N2 adsorption/desorption isotherm profile confirms the formation of micro-mesoporous materials with a specific surface area between 50-162 m2.g-1 for the supports and 112-303 m2.g-1 for the copper-based catalysts, indicating an increase in the area after the addition of Cu by impregnation due to redissolution and recrystallization of alumina phase. Catalytic tests were tested in the glycerol conversion reaction (92-15%) to added value products in order to confirm their real viability.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-01-20T20:35:40Z No. of bitstreams: 1 JeanCarlosSilvaAndrade_TESE.pdf: 5351227 bytes, checksum: 6baecb9ca1efd3ecbe1d465cdf5fbe9b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-01-21T17:57:45Z (GMT) No. of bitstreams: 1 JeanCarlosSilvaAndrade_TESE.pdf: 5351227 bytes, checksum: 6baecb9ca1efd3ecbe1d465cdf5fbe9b (MD5) / Made available in DSpace on 2016-01-21T17:57:45Z (GMT). No. of bitstreams: 1 JeanCarlosSilvaAndrade_TESE.pdf: 5351227 bytes, checksum: 6baecb9ca1efd3ecbe1d465cdf5fbe9b (MD5) Previous issue date: 2014-02-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / A demanda por materiais com alta homogeneidade obtidos a temperaturas relativamente baixas vem alavancando a busca por processos qu?micos substituintes do m?todo cer?mico convencional. Esse trabalho tem como objetivo a obten??o de pigmentos nanom?tricos encapsulados (core-shell) a base de TiO2, dopados com ?ons de metais de transi??o (Fe, Co, Ni, Al) atrav?s de 3 (tr?s) m?todos de s?ntese: precursores polim?ricos (Pechini); hidrotermal de microondas; e co-precipita??o associado ? qu?mica sol-gel. O estudo foi motivado pela simplicidade, rapidez e baixo consumo de energia caracter?sticos desses m?todos. Os sistemas de custos s?o acess?veis, pois que permitem atingir um bom controle da microestrutura, aliada a elevada pureza, com controle estequiom?trico e de fases permitindo obter part?culas de tamanho nanom?trico. As propriedades f?sicas, qu?micas, morfol?gicas, ?pticas e estruturais dos materiais obtidos foram analisadas utilizando diferentes t?cnicas de caracteriza??o de materiais. Os p?s pigmentantes foram testados na descolora??o e degrada??o utilizando um fotoreator, atrav?s da solu??o do corante remazol amarelo ouro (RNL), a partir da filtra??o destas, resultando na separa??o da solu??o filtrante e dos pigmentos, para posterior realiza??o de medidas de UV-Vis. As diferentes temperaturas de calcina??o adotadas ap?s a obten??o dos p?s, nos diferentes m?todos foram: 400 ?C a 1000 ?C. Utilizando uma concentra??o fixa de 10% (Fe, Al, Ni, Co) em massa em rela??o ? massa do tit?nio, viabilizando tecnologicamente e economicamente o estudo. Atrav?s da t?cnica de microscopia eletr?nica de transmiss?o (MET) foi poss?vel analisar e confirmar a forma??o estrutural das part?culas de pigmentos nanom?tricos encapsulados, apresentando di?metro dos p?s de TiO2 entre 20 nm e 100 nm, e espessura da camada recoberta de Fe, Ni e Co entre 2 nm e 10 nm. O m?todo de s?ntese mais eficiente entre os estudados no trabalho foi o co-precipita??o associado ? qu?mica sol-gel, no qual foram obtidos os melhores resultados, sem a necessidade da obten??o de p?s pelo processo de calcina??o / The demand for materials with high consistency obtained at relatively low temperatures has been leveraging the search for chemical processes substituents of the conventional ceramic method. This paper aims to obtain nanosized pigments encapsulated (core-shell) the basis of TiO2 doped with transition metals (Fe, Co, Ni, Al) through three (3) methods of synthesis: polymeric precursors (Pechini); hydrothermal microwave, and co-precipitation associated with the sol-gel chemistry. The study was motivated by the simplicity, speed and low power consumption characteristic of these methods. Systems costs are affordable because they allow achieving good control of microstructure, combined with high purity, controlled stoichiometric phases and allowing to obtain particles of nanometer size. The physical, chemical, morphological, structural and optical properties of the materials obtained were analyzed using different techniques for materials characterization. The powder pigments were tested in discoloration and degradation using a photoreactor through the solution of Remazol yellow dye gold (NNI), such as filtration, resulting in a separation of solution and the filter pigments available for further UV-Vis measurements . Different calcination temperatures taken after obtaining the post, the different methods were: 400 ? C and 1000 ? C. Using a fixed concentration of 10% (Fe, Al, Ni, Co) mass relative to the mass of titanium technologically and economically enabling the study. By transmission electron microscopy (TEM) technique was possible to analyze and confirm the structural formation nanosized particles of encapsulated pigment, TiO2 having the diameter of 20 nm to 100 nm, and thickness of coated layer of Fe, Ni and Co between 2 nm and 10 nm. The method of synthesis more efficient has been studied in the work co-precipitation associated with sol-gel chemistry, in which the best results were achieved without the need for the obtainment of powders the calcination process

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-23T19:49:19Z No. of bitstreams: 1 EdianaPaulaRebitski_DISSERT.pdf: 5282849 bytes, checksum: f1a7a2f4009a400f77db6f24d30a9596 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-27T19:26:26Z (GMT) No. of bitstreams: 1 EdianaPaulaRebitski_DISSERT.pdf: 5282849 bytes, checksum: f1a7a2f4009a400f77db6f24d30a9596 (MD5) / Made available in DSpace on 2016-06-27T19:26:26Z (GMT). No. of bitstreams: 1 EdianaPaulaRebitski_DISSERT.pdf: 5282849 bytes, checksum: f1a7a2f4009a400f77db6f24d30a9596 (MD5) Previous issue date: 2015-05-22 / Bionanocomp?sitos s?o materiais nanoestruturados h?bridos org?nico-inorg?nico que envolvem uma contrapartida org?nica de origem biol?gica, por exemplo, um biopol?mero, associado a um s?lido inorg?nico em nanoescala. Materiais bioh?bridos a base de argilominerais (montmorillonita, sepiolita) e s?lidos inorg?nicos (hidr?xidos duplos lamelares) s?o uma boa op??o para diversas aplica??es (tais como biom?dicas) devido ao seu baixo custo, biodegradabilidade e biocompatibilidade. Devido a capacidade de troca i?nica, ?rea espec?fica elevada e a capacidade de adsor??o que esses materiais possuem, ? poss?vel combinar uma grande variedade de esp?cies org?nicas, tais como drogas, na qualidade de transportadoras. Neste contexto, este trabalho apresenta a prepara??o de novos bionanocomp?sitos com base na combina??o dos biopol?meros carboximetilcelulose e ze?na como revestimento do h?brido, argilomineral - antibi?tico e hidr?xidos duplos lamelares-antibi?tico. Para a s?ntese dos materiais bioh?bridos foi utilizado o antibi?tico neomicina de uso t?pico e amoxicilina de uso oral como f?rmacos modelos, o qual, foram incorporados nos argilominerais e hidr?xidos duplos lamelares por processo de intercala??o por troca i?nica e por adsor??o. / Bionanocomposites systems clay base (montmorillonite and sepiolite), layered double hidroxides and biopolymers (carboxymethylcellulose and zein) were evaluated as topical delivery systems with antibacterial activity and as oral delivery systems. For this study, neomycin, a topical antibiotic, indicated mainly for open wound infections. The drug amoxicillin, an antibiotic indicated mainly for throat infections, were also used in this study. Both antibiotics were used as model drugs. Initially, drugs were incorporated directly into the biopolymer matrix, comprising the combination of carboxymethylcellulos and zein, being conformed as movies and balls and evaluated for their antibacterial activity and controlled release simulating gastrointestinal fluids. Moreover, hybrids materials have been prepared where the neomycin drug was incorporated into the lamellar inorganic solids, such as montmorillonite by ion exchange reaction, and the fibrous type, such as sepiolite by adsorption in aqueous solution. But the drug amoxicillin was incorporated into layered double hydroxides by anion exchange and montmorillonite by cation exchange. The resulting hybrids were in turn combined with the biopolymer matrix yielding bionanocomposites shaped materials such as films were tested for their antibacterial activity, and the shaped materials beads were tested for their release in the gastrointestinal fluids. Through the analysis of various physico-chemical techniques, we observed the interactions between the studied materials, the formation of hybrids materials, obtaining the bionanocomposites materials and material efficiency when applied in controlled release of drugs both topical and use oral mainly influenced by the presence of zein, are promising as topical delivery systems and oral drugs.

Made available in DSpace on 2014-12-17T14:58:23Z (GMT). No. of bitstreams: 1 MarinalvaFT_DISSERT.pdf: 2645446 bytes, checksum: d4a95fdf4bdc8c40f2876e653a2bb39f (MD5) Previous issue date: 2013-08-02 / Currently, vegetable oils have been studied for bio-lubricants base that fits the new environmental standards. Since, in a world full of finite natural resources, mineral oils bring consequences to the environment due to its low biodegradability and toxicity, also it is important to consider that synthetic oils have a high cost The aim of this work is to obtain a biolubricant additived with oxide nanoparticles (ZnO and CuO) for better resistance to friction and wear, which is not toxic to the environment and have better adherence under boundary lubrication. The methodology consisted in the synthesis of bio-lubricants (soybean and sunflower base) by epoxidation reaction. Then, some physical-chemical analysis in bio-lubricants are made to characterize theses lubricants, such as, density, acidity, iodine value, viscosity, viscosity index. Later, the lubricants were additive with nanoparticles. The tribological performance was evaluated by the equipment HFRR (High Frequency Reciprocating Rig) consisting of a wear test ball-plan type. The characterization of wear analysis was performed by SEM / EDS. The results show that bio-lubricants may be synthesized by reaction of epoxidation with good conversion. Tribological point of view, the epoxidized oils are more effective than lubricant additived with the oxide nanoparticles, they had lower coefficients of friction and better rate of film formation in the study. However, because they are environmentally friendly, bio-lubricants gain the relevant importance in tribological field / Atualmente, os ?leos vegetais tem sido base de estudo para biolubrificantes que se adequem ?s novas normas ambientais. Em um mundo cheio de recursos naturais finitos, os ?leos minerais, provenientes do petr?leo, trazem consequ?ncias ao meio ambiente devido sua baixa biodegradabilidade e toxicidade. Tamb?m deve-se considerar, os ?leos sint?ticos possuem um alto custo. O objetivo deste trabalho ? obter um biolubrificante aditivado com nanopart?culas de ?xido (ZnO e CuO) para uma melhor resist?ncia ao atrito e desgaste, que seja n?o t?xico ao meio ambiente e possua melhor ader?ncia em regime de lubrifica??o limite. Efetuou-se a s?ntese de biolubrificantes (soja e girassol) por rea??o de epoxida??o. Em seguida fizeram-se an?lises f?sico-qu?micas no biolubrificante para caracterizar os ?leos sintetizados, tais como; densidade, acidez, ?ndice de iodo, viscosidade, ?ndice de viscosidade. Posteriormente os mesmos foram aditivados com nanopart?culas. O desempenho tribol?gico foi avaliado pelo equipamento HFRR (High Frequency Reciprocating Rig), que consiste num ensaio de desgaste do tipo esfera-plano. A caracteriza??o do desgaste foi realizada atrav?s de an?lises de MEV/EDS. Os resultados demostraram que os biolubrificantes podem ser sintetizados por rea??o de epoxida??o, com boa convers?o. Do ponto de vista tribol?gico, os ?leos epoxidados puros s?o mais eficazes que os aditivados com nanopart?culas de ?xido, apresentaram menores coeficientes de atritos e melhor percentual de forma??o de filme neste estudo. Por?m, por serem ambientalmente corretos, os biolubrificantes ganham import?ncia relevante no meio tribol?gico

Made available in DSpace on 2015-04-14T13:59:06Z (GMT). No. of bitstreams: 1 457483.pdf: 5023547 bytes, checksum: e9f63d304ec1410bd1e9d8f328ceaa18 (MD5) Previous issue date: 2014-02-28 / In this work we investigated the synthesis, characterization and contrast properties of core-shell nanoparticles of iron oxide coated with dextran and functionalized with amine groups. Fluorophores groups were incorporated on the nanoparticles surface, allowing their use as contrast agents for magnetic resonance imaging and optical microscopy. The nanoparticles synthesis was performed by the coprecipitation method of iron salts in basic medium, along with the polymer coating. The synthesis parameters were modified to investigate their influence on the size distribution of nanoparticles. Transmission electron microscopy observations and dynamic light scattering showed a magnetic iron oxide core with an average diameter around 10-15 nm and the total average hydrodynamic diameters between 16-50 nm, depending on the synthesis conditions. The FTIR spectra showed characteristics absorption bands pure dextran in the synthesized core-shell nanoparticles. The zeta potential analysis showed positive values close to zero and stability at neutral pH. The magnetization curves of the nanoparticles revealed superparamagnetic behavior, with the characteristic absence of hysteresis and no magnetization at zero field. The UV-vis and flow cytometry analysis revealed the presence of fluorescent groups in the nanoparticles and the feasibility of their use in optical imaging. Studies of relaxation times of the nuclear magnetization have shown the decrease of the magnetic resonance signal with increasing nanoparticles concentration, reducing the relaxation times T1 and T2 in the nanoparticle aqueous solutions. The relaxivities ratios (r2/r1) ranged between 5.06 and 51.0 and were within the value of iron oxide contrast agents commercially available. / Neste trabalho, pesquisou-se a s?ntese, a caracteriza??o e as propriedades de contraste por imagem de nanopart?culas core-shell de ?xido de ferro, revestidas com dextran e funcionalizadas com grupos amina. Grupos fluor?foros foram incorporados na superf?cie das nanopart?culas, possibilitando seu uso como agente de contraste para imageamento por resson?ncia magn?tica e por microscopia ?ptica. As s?nteses das nanopart?culas foram realizadas pelo m?todo de coprecipita??o de sais de ferro, com o pol?mero de revestimento. Par?metros da s?ntese foram modificados para averiguar sua influ?ncia na distribui??o de tamanho das nanopart?culas. Os resultados da morfologia e da distribui??o de tamanhos por TEM e DLS mostraram um n?cleo com di?metros m?dios entre 10-15 nm e di?metros hidrodin?micos m?dios entre 16-50 nm, dependendo do procedimento de s?ntese. Os espectros de FTIR apresentaram bandas de absor??o caracter?sticas das liga??es presentes no dextran puro e nas nanopart?culas sintetizadas. A an?lise do potencial zeta revelou valores positivos pr?ximos de zero e estabilidade em pH neutro As medidas de magnetiza??o revelaram comportamento superparamagn?tico pela aus?ncia de histerese na curva de magnetiza??o. As an?lises por UV-vis e por citometria de fluxo revelaram a presen?a dos grupos fluorescentes nas nanopart?culas e a viabilidade de seu uso em imagens ?pticas. Os estudos nos tempos de relaxa??o magn?tica nuclear mostraram efeitos de contraste, perturbando a intensidade de sinal com o aumento da concentra??o, diminuindo os tempos de relaxa??o T1 e T2 das solu??es aquosas de nanopart?culas. A rela??o entre as relaxividades (r2/r1) foi entre 5.06 e 51.0, dentro dos valores dos agentes de contrastes de ?xido de ferro comercialmente dispon?veis.

Made available in DSpace on 2014-12-17T15:41:45Z (GMT). No. of bitstreams: 1 AlineAApdf.pdf: 2403213 bytes, checksum: dfc50c5f35575298ed9005c5d3fb4f7b (MD5) Previous issue date: 2009-08-14 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In this paper, the Layered Double Hydroxides (LDH s) type hydrotalcite were synthesized, characterized and tested as basic heterogeneous catalysts for the production of biodiesel by transesterification of sunflower oil with methanol. The synthesis of materials Layered Double Hydroxides (LDH s) by co-precipitation method from nitrates of magnesium and aluminum, and sodium carbonate. The materials were submitted to the variation in chemical composition, which is the amount of Mg2+ ions replaced by Al3+. This variation affects the characteristic physico-chemical and reaction the solid. The molar ratio varied in the range of 1:1 and 3:1 magnesium / aluminum, and their values between 0.2 and 0.33. This study aims to evaluate the influence of variation of molar ratio of mixed oxides derived from LDH s and the influence of impregnation of a material with catalytic activity, the KI, the rate of conversion of sunflower oil into methyl esters (biodiesel) through transesterification by heterogeneous catalysis. .The catalysts were calcined at 550 ? C and characterized by X-ray diffraction (XRD), scanning electron microscopy and energy dispersive spectroscopy of X-ray (SEM / EDS), thermogravimetric analysis (TG) and test basicity. The transesterification reaction was performed for reflux is a mixture of sunflower oil and methanol with a molar ratio of 15:1, a reaction time of 4h and a catalyst concentration of 2% by weight. The physical-chemical characterization of sunflower oil and biodiesel obtained by the route methyl submitted according NBR, EN, ASTM. Subsequently, it was with the chromatographic and thermogravimetric characterizations of oils. The results of chromatographic analysis showed that the catalysts were effective in converting vegetable oil into biodiesel, in particular the type hydrotalcite KI-HDL-R1, with a conversion of 99.2%, indicating the strong influence of the chemical composition of the material, in special due to presence of potassium in the structure of the catalyst / Neste trabalho, hidr?xidos duplos lamelares tipo hidrotalcita foram sintetizados, caracterizados e testados como catalisadores heterog?neos b?sicos para a produ??o de biodiesel por transesterifica??o de ?leo de girassol com metanol. A s?ntese dos materiais de hidr?xidos duplos lamelares (HDLs) procedeu-se pelo m?todo de co-precipita??o, a partir de nitratos de magn?sio e de alum?nio, carbonato de s?dio e hidr?xido de s?dio. Os materiais foram submetidos ? varia??o na propor??o qu?mica, que equivale ? quantidade de ?ons Mg2+ substitu?dos por Al3+. Essa varia??o afeta as propriedades f?sico-qu?micas do material. A raz?o molar variou na propor??o de 1:1 e 3:1 de magn?sio/alum?nio, estando seus valores entre 0,2 e 0,33. Realizou-se um estudo de impregna??o de iodeto de pot?ssio na estrutura dos HDLs, a fim de verificar se ocorre um aumento da basicidade nesses materiais. Os catalisadores obtidos foram calcinados ? 550 ?C e caracterizados por difra??o de raios X (DRX), microscopia eletr?nica de varredura e espectroscopia por energia dispersiva de raios X (MEV/EDS), an?lise termogravim?trica (TG) e teste de basicidade. A rea??o de transesterifica??o foi realizada refluxando-se uma mistura de metanol e ?leo de girassol com uma raz?o molar de 15:1, tempo de rea??o de 4h e uma concentra??o de 2% em massa de catalisador. A caracteriza??o f?sico-qu?mica do ?leo de girassol e dos biodieseis obtidos atrav?s da rota met?lica apresentou-se de acordo com as normas da NBR, EN, ASTM. Realizaram-se tamb?m as caracteriza??es cromatogr?ficas e termogravim?tricas dos biocombust?veis obtidos. Os resultados das an?lises cromatogr?ficas mostraram que os catalisadores foram eficientes na convers?o de ?leo vegetal em biodiesel, em especial o tipo hidrotalcita KI-HDL-R1, com uma convers?o de 99,2%, indicando a forte influ?ncia da composi??o qu?mica do material, particularmente com a presen?a do iodeto de pot?ssio na estrutura do catalisador

Made available in DSpace on 2014-12-17T15:42:16Z (GMT). No. of bitstreams: 1 LuizaPFCG_TESE.pdf: 3362653 bytes, checksum: 0de0a428d24980a5f9b2bf94d2e9214f (MD5) Previous issue date: 2012-08-23 / To overcome the challenge of meeting growing energy demand in a sustainable way, biodiesel has shown very promising as alternative energy can replace fossil fuels, even partially. Industrially, the biodiesel is produced by homogeneous transesterification reaction of vegetable oils in the presence of basic species used as catalysts. However, this process is the need for purification of the esters obtained and the removal of glycerin formed after the reaction. This context, the alternative catalysts have that can improve the process of biodiesel production, aiming to reduce costs and facilitate its production. In this study, the AlSBA-15 support with Si / Al ratio = 50 was synthesized, as like as the heterogeneous catalysts of zinc oxide and magnesium supported on mesoporous AlSBA-15 silica, in the concentrations of 5, 10, 15 and 30 %, relative to the support. The textural properties and structural characterization of catalysts and supports were determined by techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) coupled to the chemical analyzer, adsorption / desorption of N2, thermal analysis (TG / DTG), absorption spectroscopy in the infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). Characterization results indicated that the support AlSBA-15 retained the hexagonal ordered after the incorporation of zinc oxide and magnesium oxide in the holder. For heterogeneous catalysts, ZnO-AlSBA-15, that was observed the presence of zinc oxide nanoparticles dispersed in the surface and interior channels of the mesoporous and microporous support. The catalytic activity was evaluated by the transesterification reaction of sunflower oil via methylic route, and some reaction parameters were optimized with the most active catalyst in biodiesel production by sunflower oil. For the series of heterogeneous catalysts, the sample with 30 % ZnO supported on AlSBA-15 showed a better conversion of triglyceride to methyl esters, about 95.41 % of reaction conditions: temperature 175 ?C, with molar ratio of 42:1, stirring at 200 rpm and under a pressure of 14 bar for 6 h. The catalyst MgO-AlSBA-15 showed no catalytic activity in the studied reactions / Para superar o desafio de atender a crescente demanda por energia de forma sustent?vel, o biodiesel tem se demonstrado bastante promissor como alternativa energ?tica, que possa substituir os combust?veis fosseis, mesmo que parcialmente. Industrialmente, o biodiesel ? produzido atrav?s de rea??o homog?nea de transesterifica??o de ?leos vegetais na presen?a de esp?cies b?sicas utilizadas como catalisadores. Entretanto, este processo h? a necessidade de purifica??o dos ?steres obtidos e a remo??o da glicerina formada ap?s a rea??o. Diante deste contexto, tem-se buscado catalisadores alternativos, que possa aprimorar o processo de produ??o de biodiesel, visando diminuir os custos e facilitar a sua produ??o. Neste trabalho, foram sintetizados o suporte AlSBA-15 na raz?o Si/Al = 50, e os catalisadores heterog?neos de ?xido de zinco e de magn?sio suportado sobre s?lica mesoporosa AlSBA-15, nas concentra??o de 5, 10, 15 e 30 %, com rela??o ao suporte. As propriedades texturais e a caracteriza??o estrutural dos catalisadores e do suporte foram determinadas pelas t?cnicas de: difratometria de raios X (DRX), microscopia eletr?nica de varredura (MEV), microscopia eletr?nica de transmiss?o (MET) acoplada ao analisador qu?mico, adsor??o/dessor??o de N2, an?lise t?rmica (TG/DTG), espectroscopia de absor??o na regi?o do infravermelho (FTIR) e espectroscopia fotoeletr?nica de raios X (XPS). Os resultados de caracteriza??o indicaram que o suporte AlSBA-15 preservou a estrutura hexagonal ordenada, ap?s a incorpora??o do ?xido de zinco e do ?xido de magn?sio no suporte. Em rela??o aos catalisadores heterog?neos, ZnO-AlSBA-15, observou-se a presen?a de nanopart?culas de ?xido de zinco dispersas na superf?cie e no interior dos canais microporosos e mesoporosos do suporte. A atividade catal?tica foi avaliada pela rea??o de transesterifica??o do ?leo de girassol via rota met?lica, e alguns par?metros reacionais foram otimizados com o catalisador mais ativo na produ??o de biodiesel pelo ?leo de girassol. Para as s?ries de catalisadores heterog?neos, a amostra com 30 % ZnO suportado na AlSBA-15 apresentou melhor convers?o dos triglicer?deos em ?steres met?licos, cerca de 95,41 %, nas condi??es reacional de: temperatura de 175 ?C, com raz?o molar de 42:1, em agita??o de 200 rpm e sob press?o de 14 bar durante 6 h. O catalisador MgO-AlSBA-15 n?o apresentou atividade catal?tica nas rea??es estudadas

CNPq / Brazil presents an important commercial fishing pole, which turns it to become relevant considering the benefits that consumption of fish plays in human nutrition. Canned fish promotes long shelf life of these food. However, foods that are rich sources of polyunsaturated fatty acids and cholesterol, such as tuna, have a great susceptibility for lipid oxidation when exposed to thermal processing. Cholesterol oxidation products (COP?s) are related to several diseases such as atherosclerosis, and can be absorbed from the diet. Thus, this study aimed to evaluate the lipid composition and COP?s production in canned tuna purchased from metropolitan area of Rio de Janeiro. Three trademarks of ?grated in brine? and ?in oil? canned tuna were evaluated. To determinate lipid oxidation, the fatty acid composition from the methyl esters of the fish and their brine were identified using gas chromatography with flame ionisation detector; cholesterol and cholesterol oxides were determined simultaneously, using high-performance liquid chromatography and confirmed by liquid chromatograph mass spectrometer (chemical ionization interface for atmospheric pressure) (APCI-MS). Tuna in ?brine? samples presented moisture contents in a range of 24.60 to 27.23g/100g; lipids contents ranging from 4.21 to 5.59g/100g; polyunsaturated fatty acids (PUFA) levels between 9.13 to 16,20g/100g, and high saturated fatty acids (SFA) contents (in a range of 54.66 to 59.85g/100g) (dry basis-DB). The nutritional quality index showed that lipid fractions presented undesirable values. These samples presented cholesterol concentration ranging from 190.95 to 399.28mg/100g, and high cholesterol oxidation products contents (between 321.42 and 414.94?g/100g- DB). Samples of ?in oil? canned tuna presented moisture and lipids contents of 31.93 to 51.33g/100g and 23.70 to 43.99g/100g, respectively; high polyunsaturated fatty acids concentration (46.06 to 49.92g/100g), especially the w6 series; and low levels of EPA and DHA amounts (in a range of 0.59 and 1.73g/100g). Cholesterol and COP?s contents varied from 135.90 to 191.92mg/100g and from 110.97 to 207.19?g/100g, respectively. Significate concentrations of cholesterol were identified in brine (18.99 to 37.10mg/100g) and ?in oil? samples (113.09 to 259.12mg/100g), and high COP?s contents were found (in a range of 230.54 and 477.12?g/100g from brine and 44.15 to 151.18?g/100g from ?in oil? samples). It was observed that there is a transference of lipids from fish to brine, as well as migration between fish lipids and vegetable oils in the ?oil? covers, changing the fatty acids profiles of both. It is considered that the production of canned fish contributes to loss of lipid quality, promotes fatty acids oxidation and induces the formation of cholesterol oxidation products. These results indicate that is necessary to conduct further studies to evaluate the occurrence of these undesirable compounds in fish products. / O Brasil possui um importante polo de pesca comercial, fato que se torna relevante considerando os benef?cios que o consumo de pescados desempenha na nutri??o humana. As conservas de peixes promovem nestes alimentos tempos de vida ?til prolongados. Entretanto, os alimentos ricos em ?cidos graxos poliinsaturados e colesterol, como os atuns, quando submetidos ao processamento t?rmico, apresentam grande potencial para a oxida??o lip?dica. Os produtos da oxida??o do colesterol (POC?s) est?o envolvidos no desenvolvimento de doen?as, como a aterosclerose, e podem ser absorvidos a partir da dieta. Desta forma, este trabalho teve como objetivos avaliar a composi??o lip?dica e a forma??o dos POC?s em conservas de atuns comercializadas na regi?o metropolitana do Rio de Janeiro. Foram avaliadas amostras de conservas ?raladas? em ?salmoura? e em ??leo? de 3 marcas comerciais. Para determina??o da oxida??o lip?dica, identificou-se a composi??o de ?cidos graxos dos atuns e respectivos l?quidos de coberturas a partir dos ?steres met?licos, atrav?s de Cromatografia Gasosa com detector de ioniza??o por chama; al?m da quantifica??o simult?nea do colesterol e dos POC?s, atrav?s de cromatografia l?quida de alta efici?ncia e confirmados por cromat?grafo l?quido com espetr?metro de massas (interface de ioniza??o qu?mica por press?o atmosf?rica) (APCI-MS). Os atuns em ?salmoura? apresentaram m?dias entre 24,60 a 27,23g/100g de umidade; entre 4,21 a 5,59g/100g de lip?deos; teores de 9,13 a 16,20g/100g de ?cidos graxos poliinsaturados (AGPI), e elevadas concentra??es de ?cidos graxos saturados (AGS) (entre 54,66 a 59,85g/100g), em base seca (BS). Foram evidenciados nos ?ndices de qualidade nutricional das fra??es lip?dicas com valores pouco desej?veis sob o ponto de vista nutricional. As concentra??es de colesterol nessas amostras variaram entre 190,95 a 399,28mg/100g, e foram identificados elevados teores de produtos de oxida??o do colesterol (entre 321,42 e 414,94?g/g/100g), em BS. As amostras de atuns em conservas contendo ??leo? apresentaram teores entre 31,93 e 51,33g/100g de umidade; entre 23,70 e 43,99g/100g de lip?deos, elevadas concentra??es de ?cidos graxos poliinsaturados (de 46,06 a 49,92g/100g), em especial os da s?rie w6 e reduzidos teores na soma de EPA e DHA (entre 0,59 e 1,73g/100g). As concentra??es de colesterol variaram entre 135,90 e 191,92mg/100g e os POC?s de 110,97 a 207,19?g/100g. Em rela??o aos l?quidos de coberturas, foram identificadas concentra??es significativas de colesterol (de 18,99 a 37,10mg/100g nas salmouras e de 113,09 a 259,12mg/100g nos ?leos, respectivamente), al?m de elevados teores de produtos de oxida??o do colesterol (entre 230,54 e 477,12?g/100g nas salmouras e entre 44,15 e 151,18?g/100g nos ?leos). Observou-se a transfer?ncia de lip?deos dos pescados para os l?quidos em ?salmoura?, al?m da migra??o de lip?deos entre os pescados e os ?leos vegetais nas conservas em ??leo?, alterando os perfis de ?cidos graxos de ambos os meios. Considera-se que a produ??o de conservas de peixes favorece a perda da sua qualidade lip?dica, promovem oxida??o de ?cidos graxos e induzem a forma??o de produtos de oxida??o do colesterol, fato que indica a necessidade da condu??o de novos estudos que avaliem a ocorr?ncia desses compostos indesej?veis oriundos da oxida??o lip?dica em produtos de pescados.

Made available in DSpace on 2014-12-17T14:07:06Z (GMT). No. of bitstreams: 1 RayssaRNMS_DISSERT.pdf: 4171010 bytes, checksum: 0d447597643468751a7d9a8d1824c61d (MD5) Previous issue date: 2012-08-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The field of "Materials Chemistry" has been developing in recent years and there has been a great increase of interest in the synthesis and chemical and physical properties of new inorganic solids. New routes of synthesis and synthesis modified has been developed with the aim not only to optimize the processes in laboratory scale, but also on an industrial scale, and make them acceptable by current environmental legislation. The phenomenology of current solid state chemistry properties coupled with the high temperature superconductivity, ferromagnetism, porosity molecular and colors are evidence affected by the synthesis method, which in turn can influence the technological application of these materials. From this understanding, mixed oxides of nickel and zinc nanoparticulate were synthesized by microwave-assisted combustion route using three specific types of organic fuels employing the weight ratios 1:1/2 and 1:1 of cation metallic/fuel, in order to investigate the influence of such proportions to obtain the solids. The new fuels were chosen to replace, for example, urea or glycine that are the fuels most commonly preferred in this kind of synthesis. The powders without heat treatment were studied by Thermogravimetric analysis (TGA), X-Ray Diffraction (XRD) and then calcined at 900?C. After heat treatment, the samples were characterized by analysis of X Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The modified synthesis route porposed was effective for obtaining powders. Both the alternative fuels chosen as the different weight ratios employed, influenced in the morphology and obtaining oxides / O campo da Qu?mica de Materiais vem se desenvolvendo nos ?ltimos anos, tendo havido um grande aumento do interesse na s?ntese e nas propriedades qu?micas e f?sicas de novos s?lidos inorg?nicos. Novas rotas de s?nteses e s?nteses modificadas tem sido desenvolvidas com o intuito n?o apenas de otimizar os processos em escala laboratorial, como tamb?m em escala industrial, al?m de torn?-los aceit?veis pela legisla??o ambiental vigente. A atual fenomelogia da qu?mica do estado s?lido aliada ?s propriedades de supercondutividade ? alta temperatura, ferromagnetismo, porosidade molecular e cores s?o evid?ncias afetadas pelo m?todo de s?ntese, que por sua vez, podem influenciar na aplica??o tecnol?gica desses materiais. Foi a partir desta compreens?o, que ?xidos mistos de n?quel e zinco nanoparticulados foram sintetizados atrav?s da rota combust?o por microondas utilizando tr?s tipos espec?ficos de combust?veis e empregando as raz?es m?ssicas 1:1 e 1:1/2 de c?tions met?licos/combust?vel, com o intuito de averiguar a influ?ncia de tais propor??es na obten??o dos s?lidos. Os novos combust?veis foram escolhidos em substitui??o a ur?ia ou glicina que s?o mais comumente preferidos nesse tipo de s?ntese. Os p?s sem tratamento t?rmico foram estudados atrav?s da An?lise Termogravim?trica (ATG) e da Difra??o de Raios-X (DRX), sendo, em seguida, submetidos ao tratamento t?rmico ? 900?C. Ap?s as calcina??es, foram caracterizados atrav?s das an?lises Difra??o de raiosx (DRX) e Microscopia Eletr?nica de Varredura (MEV). A rota de s?ntese modificada foi eficaz para obten??o dos p?s. Tanto os combust?veis alternativos escolhidos quanto as diferentes raz?es m?ssicas empregadas, influenciaram na morfologia e na obten??o dos ?xidos

Made available in DSpace on 2014-12-17T14:09:14Z (GMT). No. of bitstreams: 1 RenataMB_TESE.pdf: 1339744 bytes, checksum: 24902b1b3636b97bbd787863d62c1f99 (MD5) Previous issue date: 2012-08-09 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The fast pyrolysis of lignocellulosic biomass is a thermochemical conversion process for production energy which have been very atratactive due to energetic use of its products: gas (CO, CO2, H2, CH4, etc.), liquid (bio-oil) and charcoal. The bio-oil is the main product of fast pyrolysis, and its final composition and characteristics is intrinsically related to quality of biomass (ash disposal, moisture, content of cellulose, hemicellulose and lignin) and efficiency removal of oxygen compounds that cause undesirable features such as increased viscosity, instability, corrosiveness and low calorific value. The oxygenates are originated in the conventional process of biomass pyrolysis, where the use of solid catalysts allows minimization of these products by improving the bio-oil quality. The present study aims to evaluate the products of catalytic pyrolysis of elephant grass (Pennisetum purpureum Schum) using solid catalysts as tungsten oxides, supported or not in mesoporous materials like MCM-41, derived silica from rice husk ash, aimed to reduce oxygenates produced in pyrolysis. The biomasss treatment by washing with heated water (CEL) or washing with acid solution (CELix) and application of tungsten catalysts on vapors from the pyrolysis process was designed to improve the pyrolysis products quality. Conventional and catalytic pyrolysis of biomass was performed in a micro-pyrolyzer, Py-5200, coupled to GC/MS. The synthesized catalysts were characterized by X ray diffraction, infrared spectroscopy, X ray fluorescence, temperature programmed reduction and thermogravimetric analysis. Kinetic studies applying the Flynn and Wall model were performed in order to evaluate the apparent activation energy of holoceluloce thermal decomposition on samples elephant grass (CE, CEL and CELix). The results show the effectiveness of the treatment process, reducing the ash content, and were also observed decrease in the apparent activation energy of these samples. The catalytic pyrolysis process converted most of the oxygenate componds in aromatics such as benzene, toluene, ethylbenzene, etc / A pir?lise r?pida da biomassa lignocelul?sica ? um processo de convers?o termoqu?mica para produ??o de energia que vem se tornando muito atratativo devido ao aproveitamento energ?tico de seus produtos: g?s (CO, CO2, H2, CH4, etc), l?quido (bio-?leo) e carv?o vegetal. O bio-?leo ? o principal produto da pir?lise r?pida, sendo a sua composi??o e caracter?sticas finais intrinsecamente relacionadas ? qualidade da biomassa (elimina??o de cinzas, teor de umidade, teor de celulose, hemicelulose e lignina) bem como ? efici?ncia da remo??o dos compostos oxigenados que causam caracter?sticas indesej?veis como aumento da viscosidade, instabilidade, corrosividade e baixo poder calor?fico. Os compostos oxigenados s?o originados no processo de pir?lise convencional da biomassa onde o uso de catalisadores s?lidos, em geral, permite a minimiza??o destes produtos melhorando a qualidade do produto final, o bio-?leo. O presente trabalho teve como objetivo avaliar os produtos da pir?lise catal?tica do capim elefante (Pennisetum purpureum Schum) utilizando catalisadores s?lidos, ?xidos a base de tungst?nio, suportados ou n?o em materiais mesoporosos do tipo MCM-41, derivados da s?lica da casca do arroz, visando ? redu??o de compostos oxigenados produzidos na pir?lise. O tratamento da biomasssa atrav?s da lavagem com ?gua aquecida (CEL) ou lavagem com solu??o ?cida (CELix), bem como a aplica??o de catalisadores a base de tungst?nio nos vapores provenientes do processo de pir?lise, teve a finalidade de melhorar a qualidade dos produtos da pir?lise. A pir?lise convencional e catal?tica da biomassa foram realizadas em um micro pirolisador, Py-5200, acoplado ao GC/MS. Os catalisadores sintetizados foram caracterizados por Difra??o de raios X, Espectroscopia na regi?o do infravermelho, Fluoresc?ncia de Raios X, Redu??o por Temperatura Programada e An?lise termogravim?trica. Estudos cin?ticos aplicando o modelo de Flynn Wall foram realizados com a finalidade de avaliar a energia de ativa??o aparente da decomposi??o t?rmica da holoceluloce nas amostras de capim elefante (CE, CEL e CELix). Os resultados mostraram a efici?ncia do processo de tratamento, reduzindo o teor de cinzas, como tamb?m foi observada a diminui??o na energia de ativa??o aparente dessas amostras. O processo de pir?lise catal?tica converteu a maioria dos produtos oxigenados do CE em arom?ticos como benzeno, tolueno, etilbenzeno, etc