<p>Catalysts play an essential role in nearly every chemical production process. Platinum supported on high surface area carbon substrates (Pt/C) is one of the promising candidates as an electrocatalyst in low temperature polymer electrolyte fuel cells. Developing the activity of the Pt/C catalyst with narrow Pt particle size distribution and good dispersion has been a main concern in current research.</p> <p><br /> In this study, the main objective was the development and characterization of inexpensive and effective nanophase Pt/C electrocatalysts. A set of modified Pt/C electrocatalysts with high electrochemical activity and low loading of noble metal was prepared by the impregnation-reduction method in this research. The four home-made catalysts synthesized by different treatments conditions were characterized by several techniques such as EDS, TEM, XRD, AAS, TGA, BET and CV.</p> <p><br /> Pt electrocatalysts supported on acid treatment Vulcan XC-72 electrocatalysts were produced successfully. The results showed that Pt particle sizes of Pt/C (PrOH)x catalysts between 2.45 and 2.81nm were obtained with homogeneous dispersion, which were more uniform than the commercial Pt/C (JM) catalyst. In the electrochemical activity tests, ORR was confirmed as a structure-sensitive reaction. The Pt/C (PrOH/pH2.5) showed promising results during chemically-active surface area investigation, which compared well with that of the commercial standard Johnson Matthey Pt/C catalyst. The active surface area of Pt/C (PrOH/pH2.5) at 17.98m2/g, was higher than that of the commercial catalyst (17.22 m2/g ) under the conditions applied. In a CV electrochemical activity test of Pt/C catalysts using a Fe2+/Fe3+ mediator system study, Pt/C (PrOH/pH2.5) (67mA/cm2) also showed promise as a catalyst as the current density is comparable to that of the commercial Pt/C (JM) (62mA/cm2).</p> <p><br /> A remarkable achievement was attained in this study: the electrocatalyst Pt supported on CNTs was synthesized effectively. This method resulted in the smallest Pt particle size 2.15nm. In the electrochemically-active surface area study, the Pt/CNT exhibited a significantly greater active surface area (27.03 m2/g) and higher current density (100 mA/cm2) in the Fe2+/Fe3+ electrochemical mediator system than the other home-made Pt/C catalysts, as well as being significantly higher than the commercial Pt/C (JM) catalysts. Pt/CNT catalyst produced the best electrochemical activities in both H2SO4 and K4[Fe(CN)6] electrolytes. As a result of the characteristics of Pt/CNT，it can be deduced that the Pt/CNT is the best electrocatalyst prepared in this study and has great potential for use in fuel cell applications.</p>

L’industrie aéronautique a exprimé un besoin en matériaux pour des zones fortement chargées thermiquement et mécaniquement. L’objectif est d’optimiser grâce à ces matériaux, notamment en termes de poids et de rendement, le coeur des turboréacteurs. Un procédé par voie liquide appelé «Reactive Melt infiltration» est industriellement envisagé pour fabriquer ces matériaux. La densification est tributaire de la compétition entre la montée capillaire et la réaction chimique entre le silicium liquide et la poudre préalablement introduite. Cette concurrence peut conduire à des phénomènes de «choking off» qui doivent être évités. Dans ce travail, l’approche numérique est à la fois macroscopique et microscopique. Des validations numériques, des applications dans le cadre de géométries modèles et des analyses physiques sont présentées pour les deux échelles. Les simulations d’imbibition réactive à l’échelle de la pièce sont effectués avec un outil développé au sein de SAFRAN alors que les simulations de montées capillaires dans des géométries modèles à l’échelle du pore sont réalisées avec le code de calcul Thétis (développé à l’I2M, Bordeaux). Une méthodologie expérimentale pour le suivi et l’analyse de l’imprégnation capillaire réactive d’un milieu granulaire constitué de matériaux modèles est également présentée. / The development of ceramic matrix composites (CMCs) to replace certain metal components ininternal hot parts of aircraft engines is an active research field for the aeronautical industry. Theseadvanced components may be manufactured with a fluid processing called ReactiveMelt Infiltration(RMI). The densification step is the capillary rise of a molten metal such as silicon within a wovenpreform. The molten metal can react with the previously introduced ceramic powder and lead to arefractory matrix. The competition between capillary rise and the reaction between molten siliconand introduced carbon powder has to be managed. The ambition is to prevent choking off effectsand closed pores created by preferential paths. Simulations of two-phase flows at macroscopic scaleare undertaken with a homemade code developed in SAFRAN whereas simulations of two-phaseflows atmicroscopic scale were undertaken with CFD code Thétis (developed at I2M, Bordeaux). Anexperimental methodology for analysis of reactive or not reactive capillary impregnation in granularmedia is described.

Student Number : 0303610W - PhD thesis - School of Chemistry - Faculty of Science / Mesoporous MCM-48 was synthesized and used as a template to synthesize mesoporous carbon (MC) materials. Polystyrene, the carbon source, together with sulfuric acid and toluene were added to the template (160 oC for 6 h) and this procedure generated a low surface area carbon supported/MCM-48 material. A repeat addition and carbonization step was needed to form the precursor carbon/MCM-48 material that was pyrolysed at 900 oC to generate graphitic mesoporous carbon materials. After removal of the silica template, mesoporous carbons were characterized by XRD, HR-TEM, Raman spectroscopy and surface area analysis. The effect of the amount of polystyrene as well as the role of the pyrolysis temperature on the final product was investigated. This synthesis methodology can readily be controlled to produce partially ordered graphitic mesoporous carbon supports with predictable pore width and surface area. The methane selectivity was low (below 6%) and stable, and the overall olefin fraction was found to be good for all the supported catalysts studied. The potassium promoter increased the hydrocarbon chain growth to C68 giving α-1 and α-2 both between 0.79 and 0.90 for all supported catalysts with an exception of MCM-48 supported Fe catalyst that selectively produced hydrocarbons up to C28.

O objetivo desta pesquisa foi estudar a formação de partículas de licopeno em pó de colágeno hidrolisado (CH) comercial usando CO2 supercrítico (CO2-SC). O estudo consistiu em três etapas: a medida de solubilidade do CH em CO2-SC por método estático para conhecer a afinidade do CH pelo CO2, a formação de partículas de misturas físicas compostas de diferentes proporções de CH/licopeno (4:1, 6:1, 8:1 e 10:1) através de processamento em uma autoclave com CO2-SC a 140 bar e 50 °C em agitação de 1.250 rpm por 45 min para definir a proporção de CH/licopeno, e o estudo do efeito de outras condições de CO2-SC (150 bar e 50 °C, 150 bar e 60 °C, 250 bar e 50 °C, 250 bar e 60 °C) na formação de partículas de licopeno em CH para identificar a melhor condição de CO2-SC. As partículas resultantes foram caracterizadas com relação à sua morfologia por microscopia eletrônica de varredura, distribuição de tamanho por difração a laser, comportamento térmico por calorimetria diferencial de varredura, estrutura química por espectroscopia de infravermelho de transformada de Fourier, liberação de carga, e estrutura física interna das partículas por microscopia de laser confocal para conhecer o mecanismo de formação das partículas pelo processamento com CO2-SC. Os resultados indicaram que o CH é pouco solúvel em CO2-SC, motivo pelo qual não há potencial para processos de micronização supercrítica relacionados à solubilidade do biomaterial carreador em CO2-SC. No estudo de proporções de CH/licopeno foi observado que o processo com CO2-SC a 140 bar e 50 °C permite a obtenção de partículas de licopeno em CH na forma de pó de coloração vermelha com intensidade dependente da quantidade de licopeno inicial, sem mudanças importantes na estrutura física porosa do CH, e um aumento de tamanho das partículas. Recomenda-se a proporção 10:1 de CH/licopeno, pois nela se evidenciou menor aglomeração de partículas e formação de fissuras na superfície das partículas que facilitam a incorporação do licopeno em CH seguindo um mecanismo de impregnação supercrítica propiciado pela sorção de CO2 e arraste simultâneo de licopeno ao interior da estrutura física das partículas de CH. Na exploração de outras condições de CO2-SC, na temperatura de 60 °C (150/250 bar) obteve-se uma massa de aparência viscoelástica sem utilidade para a formação de partículas. Entanto, na temperatura de 50 °C foi observado que as partículas de licopeno em CH formadas com CO2-SC a 150 bar, quando comparadas com as formadas com CO2-SC a 250 bar, evidenciaram formação de fissuras que resultaram na melhor dispersão e maior carga de licopeno na estrutura interna do CH. Além disso, as análises do comportamento térmico e o espectro de infravermelho destas partículas evidenciaram a formação de interações eletrostáticas entre o licopeno e o CH favorecidas pelo processamento com CO2-SC. Assim, conclui-se que o processamento com CO2-SC a 140/150 bar e 50 °C poderia ser utilizada para o design de partículas de licopeno impregnadas em CH, gerando um ingrediente com possível ampla atividade funcional pela atividade biológica do CH em tecidos conjuntivos e pela atividade antioxidante do licopeno. / The objective of this research was to study the formation of lycopene particles in commercial powder of hydrolyzed collagen (HC) using supercritical CO2 (SC-CO2). The study consisted of three steps: the solubility measurement of HC in SC-CO2 by static method to know the affinity of HC by CO2, the formation of particles of physical mixtures composed of different ratios of HC/lycopene (4:1, 6:1, 8:1 and 10:1) by autoclaving with SC-CO2 at 140 bar and 50 °C under stirring at 1,250 rpm for 45 min to define the HC/lycopene ratio, and the study of the effect of other conditions of SC-CO2 (150 bar and 50 °C, 150 bar and 60 °C, 250 bar and 50 °C, 250 bar and 60 °C) in the particle formation of lycopene in HC to identify the best SC-CO2 condition. The resulting particles were characterized with respect to their morphology by scanning electron microscopy, size distribution by laser diffraction, thermal behavior by differential scanning calorimetry, chemical structure by Fourier transform infrared spectroscopy, charge release, and physical structure of the particles by confocal laser microscopy to know the mechanism of particle formation by SC-CO2 processing. The results indicated that HC is poorly soluble in SC-CO2 and therefore has no potential for supercritical micronization processes related to the solubility of the biomaterial in SC-CO2. In the study of ratios of HC/lycopene it was observed that the process with SC-CO2 at 140 bar and 50 °C allowed to obtain lycopene particles in HC with powder appearance of red color with intensity depending on the amount of initial lycopene, without important changes in the porous physical structure of HC, and an increase in particle size. It is recommended a 10:1 ratio of HC/lycopene, since this ratio showed less particle agglomeration, and formation of fissures on the surface of the particles facilitating the incorporation of lycopene into HC following a mechanism of supercritical impregnation propitiated by CO2 sorption and simultaneous drag of lycopene to the interior of the physical structure of the HC particles. In the exploration of other conditions of SC-CO2, at 60 °C (150/250 bar) a mass of viscoelastic appearance was obtained without utility for the formation of particles. However, at 50 °C was observed that the lycopene particles in HC formed with SC-CO2 at 150 bar, when compared with the particles formed with SC-CO2 at 250 bar evidenced the formation of fissures, which had positive influence in the dispersion and charge of lycopene in the internal structure of HC. In addition, analyzes of the thermal behavior and the infrared spectrum of these particles evidenced the formation of electrostatic interactions between lycopene and HC favored by SC-CO2 processing. Thus, it can be concluded that SC-CO2 processing at 140/150 bar and 50 °C could be used for the design of lycopene particles impregnated in HC, producing an ingredient with possible broad functional activity due to the biological activity of HC in connective tissues and the antioxidant activity of lycopene.

Made available in DSpace on 2017-07-21T20:42:33Z (GMT). No. of bitstreams: 1 Juliana de Oliveira Pimenta.pdf: 2102034 bytes, checksum: c49b6619822775178bcdf4c3da21de3c (MD5) Previous issue date: 2011-01-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents a study on the preparation of titanium dioxide thin films (TiO2) on a substrate of glass slides using the forced impregnation method for control of pressure and temperature. A temperature of 320 ° C with a constant pressure of 1,80 MPa was used to prepare the films; the samples were exposed for 24 hours at this condition. The films were characterized by X-ray diffraction which confirmed the presence of TiO2 on the surface of the substrate and the morphology was analyzed by conventional and field-emission gun scanning electron microscopy. The films of titanium dioxide were used for bacteriological testing. The controlled variables in the bacteriological tests were: the temperature for bacterial growth, growth time, sterilization of the environment and materials and quality of bacterial medium cultures. The bioactivity of TiO2 was tested with Escherichia coli by standard method, with growth in an oven for 24h at 37 °C and analyzed by absorption spectrophotometry with readings in the range of 600nm. The films showed effective bacteriostatic by growth inhibiting the growth of Escherichia coli compared to substrates without film. (Σlog Abs = 73,7 with film against Σlog Abs = 75,0 without thin film E ±10-1). / Neste trabalho foi desenvolvido um estudo sobre a preparação de filmes finos de dióxido de titânio (TiO2) em substrato de lamínulas de vidro utilizando o método de impregnação forçada por controle de pressão e de temperatura. Para a preparação dos filmes, utilizou-se a temperatura de 320ºC com pressão constante de 1,80 MPa exposto por período de 24 horas. Os filmes obtidos foram caracterizados por difração de raios X que confirmaram a presença de TiO2 na superfície dos substratos e, a morfologia, analisada por microscopia eletrônica de varredura convencional e por força de campo de emissão. Os filmes de dióxido de titânio foram utilizados para ensaios bacteriológicos. As variáveis controladas nos ensaios bacteriológicos foram à temperatura para o crescimento das bactérias, o tempo de crescimento, a esterilização do ambiente e materiais e a qualidade das culturas de bactérias e meio estéril. A bioatividade do TiO2 foi testada com Escherichia coli por um método padrão, com crescimento por 24 h a 37 ºC e analisada por espectrofotometria de absorção com leituras na faixa de 600 nm. Os filmes mostraram eficiente poder bacteriostático inibindo o crescimento da Escherichia coli se comparado com substratos sem o filme. (Σlog Abs = 73,7 com filme contra Σlog Abs = 75,0 sem filme fino E ±10-1).

O trabalho tem por finalidade o estudo teórico e experimental de ligações em estruturas de madeira com cavilhas de madeira de seção cilíndrica impregnadas com resinas estirênicas. A impregnação da madeira tem como objetivos: diminuir o processo de degradação, retardação ao fogo, melhorar a estabilidade dimensional e aumentar as propriedades de resistência e elasticidade da madeira. Foram determinados experimentalmente as características de resistência e elasticidade do material e posteriormente realizados ensaios de ligações padronizados com solicitação paralela e normal às fibras. Os resultados dos ensaios mostram aumento na resistência de compressão normal até 292% e aumento de 80% no limite de proporcionalidade da ligação. A madeira utilizada para a impregnação foi o Pinus de reflorestamento. / The aim of this work is a theorytical and experimental studies of joints in timber structures with wooden dowels of circular cross section impregnated with styrenic resins. The objetives of wood impregnation are to decrease the deterioration process, to promote fire retardation, to improve dimensional stability and mainly increase the compression strength and stiffiness of wood. The strength and stiffness properties of the material are determined. Standard joints tests are carried out in compression both parallel and perpendicular to grains. The test results increases of compression perpendicular strength up to 292% and the up to 80% proportional limit joint. The wood used for impregnation was Pinus from reforestation sites.

Made available in DSpace on 2014-12-17T15:41:58Z (GMT). No. of bitstreams: 1 AdrianaPBS_DISSERT.pdf: 2596487 bytes, checksum: f09071ef3141cb36b73492e4246e301b (MD5) Previous issue date: 2012-03-15 / O recente interesse em se obter materiais nanoporosos funcionalizados para aplica??es como calisadores heterog?neos e adsor??o de CO2, tem aumentado no meio industrial e cientifico. Nesta ?ltima aplica??o, a introdu??o de grupos aminas, como os presentes em quitosana, em materiais nanoporosos do tipo SBA-15 para gerar intera??es espec?ficas com o CO2 tem ganhado import?ncia. Assim, neste trabalho foram realizadas a s?ntese do SBA-15 e posterior impregna??o da CS no suporte mesoporoso atrav?s do m?todo de impregna??o por via ?mida. Os materiais obtidos foram caracterizados por meio DRX, TG, DSC, MEV, FTIR e adsor??o/dessor??o de N2. Os resultados de DRX indicaram que a estrutura ordenada do suporte SBA-15 foi preservada ap?s a impregna??o e os c?lculos mostraram que o di?metro m?dio do poro e/ou a espessura m?dia da parede (wt) foram alterados devido a introdu??o da quitosana nas amostras funcionalizadas. As curvas de TG e de DSC,corroboraram com os dados de DRX, indicando a presen?a da quitosana na estrutura mesoporosa do SBA-15, assim como as micrografias das amostras funcionalizadas, que possibilitou visualizar o estado de agrega??o do material obtido. As bandas caracter?sticas de absor??o da CS na regi?o IV foram identificadas e interpretadas nas amostras funcionalizadas confirmando as outras caracteriza??es. Foi visto tamb?m que a ?rea superficial diminuiu nas amostras funcionalizadas, indicando a sucessiva incorpora??o do pol?mero no suporte mesoporoso. A energia de ativa??o do processo de degrada??o t?rmica da quitosana impregnada no suporte foi determinada por meio do m?todo de cin?tica livre de Viazovkin e pelo m?todo de Ozawa-Flay-Wall com os resultados indicando que o aumento da quitosana diminui em aproximadamente 10% a energia de ativa??o para sua degrada??o.

Made available in DSpace on 2014-12-17T15:41:59Z (GMT). No. of bitstreams: 1 AdrianaPBS_DISSERT.pdf: 2596487 bytes, checksum: f09071ef3141cb36b73492e4246e301b (MD5) Previous issue date: 2012-03-15 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The recent interest in obtaining functionalized nanoporous materials for applications such as heterogeneous catalysts and adsorption of CO2 has increased today. In the latter application, the introduction of amino groups such as present in the chitosan (CS), in the nanoporous materials like SBA-15 to generate specific interactions with CO2 has gained importance. In this work were performed to hydrothermal synthesis of SBA-15 and subsequent impregnation of the CS in the support mesoporous by the method of the wet impregnation. The materials were characterized by TG/DTG, DSC, XRD, SEM, FTIR and adsorption / desorption of N2. The XRD showed that the ordered structure of the support SBA-15 was preserved after the impregnation and calculations have shown that the average pore diameter (Dp) and / or the average wall thickness (wt) have been changed due to introduction of the CS in the samples functionalized. The curves of TG and DSC data corroborates the XRD, indicating the presence of CS in the nanoporous structure of SBA-15, as well as micrographs of samples, which allowed the display state of aggregation of the material obtained. The characteristics of bands absorption in the region of the CS in the FTIR were identified and interpreted in the samples functionalized, confirming the further characterization. Measurements showed that the BET surface area decreases in the functionalized samples, indicating the successive incorporation of the polymer in the nanoporous support. The activation energy apparent (Ea) for the process of thermal degradation of CS in the impregnated support was determined by the methods of kinetic freedom Vyazovkin and Ozawa-Flynn-Wall with the results indicating that the sample functionalized CS/SBA-15 2,5 % was decrease of the Ea in their degradation of about 10% compared to 1,0 % CS/SBA-15 sample / O recente interesse em se obter materiais nanoporosos funcionalizados para aplica??es como catalisadores heterog?neos e na adsor??o de CO2 tem aumentado atualmente. Nesta ?ltima aplica??o, a introdu??o de grupos aminas, como os presentes na quitosana (CS), em materiais nanoporosos do tipo SBA-15 para gerar intera??es espec?ficas com o CO2 tem ganhado import?ncia. Assim, neste trabalho foram realizadas a s?ntese hidrot?rmica do SBA- 15 e posterior impregna??o da CS no suporte mesoporoso atrav?s do m?todo de impregna??o por via ?mida. Os materiais obtidos foram caracterizados por meio de TG/DTG, DSC, DRX, MEV, FTIR e adsor??o/dessor??o de N2. Os resultados de DRX indicaram que a estrutura ordenada do suporte SBA-15 foram preservada ap?s a impregna??o e os c?lculos mostraram que o di?metro m?dio do poro (Dp) e/ou espessura m?dia da parede (wt) foram alterados devido a introdu??o da CS nas amostras funcionalizadas. As curvas de TG e DSC corroboraram com os dados de DRX, indicando a presen?a da CS na estrutura mesoporosa do SBA-15, assim como as micrografias das amostras funcionalizadas, que possibilitou visualizar o estado de agrega??o do material obtido. As bandas caracter?sticas de absor??o da CS da regi?o IV foram identificadas e interpretadas nas amostras funcionalizadas, confirmando as outras caracteriza??es. As medidas de BET mostraram que a ?rea superficial diminui nas amostras funcionalizadas, indicando a sucessiva incorpora??o do pol?mero no suporte nanoporoso. A energia de ativa??o aparente (Ea) do processo de degrada??o t?rmica da CS impregnada no suporte foi determinada por meio dos m?todos de cin?tica livre de Vyazovkin e de Ozawa-Flynn-Wall com os resultados indicando que a amostra funcionalizada CS/SBA-15 2,5 % teve uma diminui??o da Ea para a sua degrada??o de aproximadamente de 10% em rela??o a amostra de CS/SBA-15 1,0 %

Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-02-04T13:32:20Z No. of bitstreams: 2 Dissertação - Regiane Lopes dos Santos - 2010.pdf: 2296508 bytes, checksum: 8c7da40e51ba04f72f1319279074de08 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-02-11T11:27:11Z (GMT) No. of bitstreams: 2 Dissertação - Regiane Lopes dos Santos - 2010.pdf: 2296508 bytes, checksum: 8c7da40e51ba04f72f1319279074de08 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-02-11T11:27:12Z (GMT). No. of bitstreams: 2 Dissertação - Regiane Lopes dos Santos - 2010.pdf: 2296508 bytes, checksum: 8c7da40e51ba04f72f1319279074de08 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2010-10-01 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Potassium tetratitanate (K2Ti4O9) and sodium trititanate (Na2Ti3O7) were synthesized by solid state reaction at 800°C and wet impregnated using Mg2+/La3+ or nanoparticles of MgO/La2O3 varying ion/oxide content in 1, 5 or 10% of matrix weight. MgO and La2O3 synthesized by precipitation method and their mean crystallite size calculated in 11 nm and 72 nm, respectively. Synthesized materials were characterized by X ray diffractometry, termogravimetry, N2 adsorption, mid-infrared spectroscopy, transmission electron microscopy and they were applied on transesterification reactions using mixtures of methyl acetate/ethanol and ethyl acetate/methanol. Interlayer distance calculated for solids is about 8 Å. Impregnation of ion/oxide in matrices K2Ti4O9 and Na2Ti3O7 produced structural changes like loss of crystallinity for some of them including peak broadening or disappearing. All synthesized materials, after burning in an atmosphere of N2 (g), lost mass related to the exit of surface water and interlamellar water. Materials showed low surface area, with values below 5 m2/g. In general, powder utilized had conversion rates between 10 and 80%. Emphasis should be given to pure matrices which presented conversions rates equal or higher than impregnated powders, and the use of matrix K2Ti4O9 led to better results. Among the oxides chosen for impregnation, higher efficiency was observed for MgO. Some powders were reused for the same reactions and its activity decreased in each reaction cycle. Reaction mixture analysis after reuse tests to K2Ti4O9 revealed partial leaching of K+ ions, however XRD patterns profile analysis did not show structural changes occurrence. A proposal to explain layered titanate activity on transesterification reactions is made based on acid-base properties of layers and output of K+ from interlamellar area. / Tetratitanato de potássio (K2Ti4O9) e trititanato de sódio (Na2Ti3O7) foram sintetizados por meio de síntese no estado sólido a 800°C, impregnados por via úmida utilizando Mg2+/La3+ ou nanopartículas de MgO/La2O3 variando o teor do íon/óxido em 1, 5 ou 10% em relação à massa da matriz. MgO e La2O3 foram sintetizados por precipitação e tiveram seu diâmetro médio de cristalito calculados em 11 nm e 72 nm, respectivamente. Os materiais sintetizados foram caracterizados por difratometria de raios X, termogravimetria, fisissorção de N2(g), espectroscopia na região do infravermelho médio, microscopia eletrônica de transmissão e foram aplicados em reações de transesterificação utilizando misturas reacionais acetato de metila/etanol e acetato de etila/metanol. A distância interlamelar calculada para os sólidos é da ordem de 8 Å. A impregnação dos íons/óxidos nas matrizes K2Ti4O9 e Na2Ti3O7 produziu mudanças estruturais incluindo perda de cristalinidade para algumas delas incluindo alargamento ou desaparecimento de picos. Todos os materiais sintetizados, após queima sob atmosfera de N2(g), perderam massa relativa à saída de água superficial e água interlamelar. Os materiais apresentaram baixa área superficial, com valores abaixo de 5 m2/g. De um modo geral, os pós utilizados tiveram taxas de conversão entre 10 e 80%. Destaque deve ser dado às matrizes puras que apresentaram taxas de conversão iguais ou superiores aos pós impregnados, sendo que o uso da matriz K2Ti4O9 levou aos melhores resultados. Dentre os óxidos escolhidos para a impregnação, a eficiência maior foi observada para MgO. Alguns pós foram reutilizados para as mesmas reações e a atividade diminuiu a cada ciclo de reação. A análise da mistura reacional após os testes de reuso para a matriz K2Ti4O9 revelou lixiviação parcial de íons K+, entretanto a análise do perfil dos padrões de DRX dos pós após reuso não revelou a ocorrência de mudanças estruturais. Uma proposta para explicar a atividade dos titanatos lamelares nas reações de transesterificação é feita baseando-se nas propriedades ácido-base das lamelas e na saída de íons K+ da região interlamelar.

L’industrie, quel que soit son domaine d’activité, produit une quantité importante d’effluents chargés, couramment appelés coproduits. La gestion et le traitement de ces eaux usées sont aujourd’hui strictement encadrés car leurs propriétés physiques et leurs compositions chimiques interdisent leurs rejets directs vers le milieu naturel. Cependant, la présence en forte concentration de certains éléments valorisables tels que les sels minéraux ou des composés organiques dans certains de ces effluents, leurs confèrent alors de nouvelles propriétés qui trouvent échos dans diverses applications (fertilisation des sols, alimentation animale, méthanisation, co-compostage, etc.). Le carbone étant le constituant majoritaire de tout combustible, une valorisation thermique par combustion en chaudière biomasse des effluents organiques semble être une alternative envisageable. L’objet de cette thèse est l’étude de cette voie de valorisation énergétique et de la faisabilité de cette application. Du fait de leur état liquide, les effluents seuls sont de mauvais combustibles comparés aux biomasses standards (plaquettes forestières, paille, etc.). Les travaux de recherche se concentrent donc sur l’étude et la caractérisation de biomasses en tant que support d’imprégnation, puis sur la formulation d’un co-combustible homogène imprégné d’un effluent organique industriel. Les biomasses sont en effet connues dans la littérature pour avoir des propriétés d’adsorption et d’absorption intéressantes. Une étude paramétrique à l’échelle du laboratoire a été menée afin de quantifier la capacité d’imprégnation et la sélectivité de différents types de biomasse vis-à-vis de l’effluent choisi. Le but était également de déterminer les paramètres qui influençaient l’imprégnation afin de modéliser les phénomènes. Suite à cela, des essais à l’échelle pilote sur une installation de combustion de 40 kW ont été effectués en vue de vérifier la conformité des combustibles imprégnés en termes d’émissions à la cheminée et dans l’optique de préparer le changement d’échelle pour une potentielle application industrielle. / Important amounts of organic effluents, also called wastewaters or byproducts, are produced whatever the type of industry which is considered. Nowadays, the wastewaters management and treatment are strictly controlled since the physical properties and the chemical composition of these byproducts disallow the direct reject through natural media. However, the presence of some specific compounds confers to effluents new advantages and opens the door to several applications (such as soil fertilization, cattle feed, methanization, co-composting, etc.). Carbon being the main component of every fuel, the thermal valorization of these organic effluents by combustion in a standard biomass boiler seems to be possible. The study of this recovery method and its feasibility are the subjects of the thesis here. Due to their liquid state, effluents alone cannot be considered as fuels compared to standard biomass (woodchips, straw, etc.). Therefore research works are focused on study and characterization of biomasses as impregnation base, then formulation of fuels impregnated with an industrial organic effluent. Indeed, the adsorptive and absorptive properties of biomasses are well-known in the literature. A parametric study at laboratory scale was carried out in order to quantify the impregnation capacity of different types of biomass regarding the effluent. The main goal was also to highlight the parameters which influence the impregnation in order to modeling the phenomenon. Then impregnation and combustion tests were performed at pilot scale using a biomass boiler of 40 kW to ensure the conformity of impregnated fuels in terms of stack emissions. This part of the work was conducted with the perspective of preparing the process scale-up for a potential industrial utilization.