Climent Terol, E. (2012). Design of new hybrid materials: Study of its application in new detection formats and in controlled release applications [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17939 / Palancia

Made available in DSpace on 2014-12-17T15:41:56Z (GMT). No. of bitstreams: 1 LidianeAM_DISSERT.pdf: 1970613 bytes, checksum: 036cbfe77378ec3746e57700b6ed691b (MD5) Previous issue date: 2012-01-30 / Volatile Organic Compounds are pollutants coming mainly from activities that use fossil fuels. Within this class are the BTEX (benzene, toluene, ethylbenzene and xylenes) compounds that are considered hazardous. Among the various existing techniques for degradation of pollutants, there is advanced oxidation using H2O2 generating hidoxil radical ( OH). In this work, the mesoporous material of MCM-41 was synthesized by hydrothermal method and then was used as support, the impregnation of titanium by the method of synthesis with excess solvent to obtain the catalyst Ti-MCM-41. The catalyst was used in the reaction catalyzed removal of BTEX in water using H2O2 as oxidant. The materials were characterized by: XRD, TG/DTG, FTIR, nitrogen adsorption-desorption and FRX-EDX, in order to verify the method of impregnation of the mesoporous titanium support was effective. Catalytic tests were carried out in reactors of 20 mL containing BTEX (100.0 μg/L), H2O2 (2.0 M) and Ti-MCM-41 (2.0 g/L) in acid medium. The reaction occurred for 5 h at 60 ?C and analysis were performed by gas chromatography with photoionization detector and static headspace sampler. The characterizations have proven the effectiveness of the synthesis method used and the incorporation of titanium lt in the support. The catalytic tests showed satisfactory results with conversion of more than 95 % for the studied compounds, where the catalyst 48% Ti-MCM-41 showed a higher removal efficiency of the compounds under study / Os Compostos Org?nicos Vol?teis s?o poluentes oriundos, principalmente, de atividades que utilizam combust?veis fosseis. Dentro desta classe encontram-se os BTEX (benzeno, tolueno, etilbenzeno e xilenos) que s?o compostos considerados perigosos. Dentre as varias t?cnicas existentes para degrada??o de poluentes, destaca-se a oxida??o avan?ada utilizando H2O2 para gera??o do radical hidoxil ( OH). Neste trabalho, o material mesoporoso do tipo MCM-41 foi sintetizado atrav?s do m?todo hidrot?rmica e em seguida foi utilizado como suporte, na impregna??o de tit?nio pelo m?todo p?s-s?ntese com excesso de solvente para a obten??o do catalisador Ti-MCM-41. O catalisador foi utilizado na cat?lise da rea??o de remo??o dos BTEX em meio aquoso utilizando H2O2 como oxidante. Os materiais obtidos foram caracterizados por: DRX, TG/DTG, FTIR, adsor??o/dessor??o de N2, FRX-EDX, com o objetivo de verificar se o m?todo de impregna??o do tit?nio no suporte mesoporoso foi eficiente. Os testes catal?ticos foram realizados em reatores de 20 mL contendo solu??o aquosa de BTEX (100,0 μg/L), H2O2 (0,1 M) e Ti-MCM-41 (2,0 g/L) em meio acido. A rea??o ocorreu por 5 h a 60 ?C e as analises foram feitas por cromatografia a g?s com detector de fotoionizacao e amostrador por headspace est?tico. As caracteriza??es comprovaram a efic?cia do m?todo de s?ntese utilizado, assim como a incorpora??o do tit?nio no suporte. Os testes catal?ticos apresentaram resultados satisfat?rios na remo??o de mais de 95 % para os compostos estudados, onde o catalisador 48% Ti-MCM-41 apresentou uma maior efici?ncia na remo??o dos compostos em estudo

The interest in hydrogen as a clean energy source has increased due to depletion of limited fossil resources and environmental impact related to CO2 emissions. Hydrogen production from bio-ethanol, which already contains large amount of water, by steam reforming reaction, has shown excellent potential with CO2 neutrality. However, steam reforming of ethanol reaction is a highly complex process including many side reactions which decrease hydrogen yield and have a negative effect on process economy. Also, thermodynamic limitations cause decrease in hydrogen yield. In the present study, a new reaction process called sorption enhanced steam reforming has been investigated to improve hydrogen yield in ethanol reforming over Ni and Co impregnated MCM-41 type mesoporous catalysts. In this process in-situ removal of CO2 by CaO was used to improve hydrogen yield significantly. Catalysts play a crucial role in both steam reforming of ethanol and sorption enhanced steam reforming of ethanol reactions. Discovery of mesoporous catalyst supports, like MCM-41, started a new pathway in catalysis research. In this study, Co and Ni incorporated MCM-41 type materials having metal/Si molar ratio of 0.1 were synthesized by impregnation method, characterized and tested in both steam reforming of ethanol and sorption enhanced steam reforming of ethanol reactions at 500oC, 550oC and 600oC. EDS and XRD results of the synthesized catalysts showed that Co and Ni were successfully incorporated and well dispersed in the MCM-41 support. The characteristic ordered pore structure of MCM-41 was partially conserved. Synthesized Co-MCM-41 and Ni-MCM-41 had surface area and pore diameter values of 303.6 m2/g &ndash / 1.98 nm and 449 m2/g &ndash / 2.2 nm, respectively. Catalytic test results obtained with both catalysts proved that hydrogen yield values were significantly enhanced in the presence of CaO during in situ capture of CO2. Catalytic performance of Ni-MCM-41 was much better than Co-MCM-41 in ethanol reforming reaction. The highest hydrogen yield obtained with Co-MCM-41 catalyst was achieved at 550oC as 3.1 with in situ capture of CO2. This value is not high enough for practical use of this catalyst. At the same temperature, the corresponding hydrogen yield value was only 1.62 in the absence of CaO. The catalytic test results obtained with Ni-MCM-41 at 600oC, gave a hydrogen yield value of 5.6 in the sorption enhanced reforming run, which is about 94% of the maximum possible hydrogen yield of six.

Made available in DSpace on 2014-12-17T14:07:04Z (GMT). No. of bitstreams: 1 AndersonJS_DISSERT.pdf: 4871519 bytes, checksum: 507c2ee7d7475d1557abdee7e257a648 (MD5) Previous issue date: 2012-12-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The MCM-41 mesoporous synthesis was done using rice hulls ash and chrysotile as natural alternative silica sources. For the using of these sources, chemical and thermic treatments were done in both materials. After chemical and thermic treatments, these materials were employed on the MCM-41 mesoctructures synthesis. The natural materials treated and employed in the synthesis were characterized by several techniques such as X-ray diffraction, N2 adsorption and desorption, scanning electronic microscopy and thermogravimetric analysis. MCM-41 standart samples synthetized with aerosil 200 commercial s?lica were used to evaluation. The formed material from rice hulls ash showed values from BET specific area about 468 m?.g-1, N2 adsorption and desorption isotherms and loss mass similar to reference materials. The silica from chrysotile calcined and leached was employed to mesoporous materials synthesis. The BET specific area showed values about 700 m?.g-1, N2 adsorption and desorption isotherms type IV and loss mass similar to mesoporous materials. The formed material from calcined and leached chrysotile, without calcination, applied to phenol remotion carried high performance liquid chromatography and evaluated with organophilic clays with different treatments. By the characterization techniques were proved that mesoporous materials with lesser order that reference samples. The material formed from rice hulls ash without the calcination step achieved better adsorption results than organophilic clays / A s?ntese dos mesoporosos do tipo MCM-41 foram realizadas empregando materiais naturais como cinza da casca de arroz e crisotila como fontes alternativas de s?lica. Para a utiliza??o destas fontes, tratamentos t?rmicos e qu?micos foram realizados em ambos os materiais. Os materiais naturais, ap?s tratamento t?rmico e qu?mico, foram empregados na forma??o de mesoestruturas do tipo MCM-41. Os materiais naturais, tratados e empregados na s?ntese foram caracterizados por diversas t?cnicas, como difra??o de raios-X, adsor??o e dessor??o de N2, microscopia eletr?nica de varredura e an?lise termogravim?trica. Amostras padr?es de MCM-41 sintetizadas com s?lica comercial pirolisada aerosil 200 foram utilizadas como crit?rio de compara??o. O material formado a partir da cinza da casca de arroz calcinada e lixiviada apresentou ?rea espec?fica de 468 m?.g-1, isotermas de adsor??o e dessor??o de N2 t?picas de materiais mesoporosos e eventos de perda de massa semelhantes a amostra de refer?ncia. A s?lica derivada da crisotila calcinada e lixiviada foram utilizadas para a s?ntese de materiais mesoporosos. O material apresentou valores de ?rea espec?fica BET de 700 m?.g-1, isotermas de adsor??o e dessor??o de N2 do tipo IV e perdas de massa caracter?sticas de materiais mesoporosos. O material formado a partir da cinza da casca de arroz, sem a etapa de calcina??o foi aplicado na adsor??o de fenol acompanhado por cromatografia l?quida de alta efici?ncia (CLAE) e comparado com argilas organof?licas com diversos tratamentos. Pelas t?cnicas de caracteriza??o comprova-se que os materiais s?o do possuem menor ordena??o que a amostra de refer?ncia. O material formado a partir da cinza da casca de arroz, e sem a etapa de calcina??o, obteve melhores resultados de adsor??o de fenol, se comparado ?s argilas organof?licas

Made available in DSpace on 2014-12-17T14:07:15Z (GMT). No. of bitstreams: 1 MariaSBF_TESE.pdf: 2706042 bytes, checksum: e909d3cb5ee177d47cc6917725b38335 (MD5) Previous issue date: 2013-05-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In recent years, the area of advanced materials has been considerably, especially when it comes to materials for industrial use, such as is the case with structured porosity of catalysts suitable for catalytic processes. The use of catalysts combined with the fast pyrolysis process is an alternative to the oxygenate production of high added value, because, in addition to increasing the yield and quality of products, allows you to manipulate the selectivity to a product of interest, and therefore allows greater control over the characteristics of the final product. Based on these arguments, in this work were prepared titanium catalysts supported on MCM-41 for use in catalytic pyrolysis of biomass, called elephant grass. The reactions of pyrolysis of biomass were performed in a micro pyrolyzer, Py-5200, coupled to GC / MS, the company CDS Corporation, headquartered in the United States. The catalysts Ti-MCM-41 in different molar ratios were characterized by XRD, TG / DTG, FT-IR, SEM, XRF, UV-visible adsorption of nitrogen and the distribution of particle diameter and specific surface area measurement by the BET method. From the catalytic tests it was observed that the catalysts synthesized showed good results for the pyrolysis reaction.The main products were obtained a higher yield of aldehydes, ketones and furan. It was observed that the best reactivity is a direct function of the ratio Si/Ti, nature and concentration of the active species on mesoporous supports. Among the catalysts Ti-MCM-41 (molar ratio Si / Ti = 25 and 50), the ratio Si / Ti = 25 (400 ? C and 600 ? C) favored the cracking of oxygenates such as acids , aldehydes, ketones, furans and esters. Already the sample ratio Si / Ti = 50 had the highest yield of aromatic oxygenates / Nos ?ltimos anos, a ?rea de materiais tem avan?ado consideravelmente, principalmente, quando se trata de materiais para uso industrial, como ? o caso de catalisadores estruturados com porosidade adequada para os processos catal?ticos. O uso de catalisadores combinados ao processo de pir?lise r?pida ? uma alternativa para a produ??o de compostos oxigenados de alto valor agregado, pois, al?m de elevar o rendimento e qualidade dos produtos, permite manipular a seletividade para um produto de interesse e, portanto, permite um maior controle sobre as caracter?sticas do produto final. Com base nesses argumentos, neste trabalho foram preparados catalisadores de tit?nio suportados em MCM-41 para uso em pir?lise catal?tica da biomassa, denominada de capim elefante. As rea??es de pir?lise da biomassa foram realizadas em um micro pirolisador, Py-5200, acoplado ao GC/MS, da empresa CDS Corporation, sediada nos Estados Unidos. Os catalisadores Ti-MCM-41, em diferentes raz?es molares, foram caracterizados por DRX, TG/DTG, FT-IR, MEV, FRX, UV-Vis?vel, adsor??o de nitrog?nio, distribui??o de di?metro de part?culas e medidas de ?rea espec?fica pelo m?todo BET. A partir dos testes catal?ticos foi poss?vel observar que os catalisadores sintetizados apresentaram bons resultados para a rea??o de pir?lise. Entre os catalisadores Ti-MCM-41 (raz?es molares Si/Ti = 25 e 50), o de raz?o Si/Ti=25 (temperatura de 400?C e 600?C) favoreceu o craqueamento de compostos oxigenados, tais como, ?cidos, alde?dos, cetonas, furanos e ?steres. J? a amostra de raz?o Si/Ti = 50 apresentou maior rendimento de arom?ticos oxigenados

Made available in DSpace on 2014-12-17T14:08:49Z (GMT). No. of bitstreams: 1 AruzzaMMA_DISSERT.pdf: 1774693 bytes, checksum: a3fe2aad8bc5ee5d62f0d84e6a4733c6 (MD5) Previous issue date: 2011-07-01 / The use of biofuels remotes to the eighteenth century, when Rudolf Diesel made the first trials using peanut oil as fuel in a compression ignition engine. Based on these trials, there was the need for some chemical change to vegetable oil. Among these chemical transformations, we can mention the cracking and transesterification. This work aims at conducting a study using the thermocatalytic and thermal cracking of sunflower oil, using the Al-MCM-41 catalyst. The material type mesoporous Al-MCM-41 was synthesized and characterized by Hydrothermical methods of X-ray diffraction, scanning electron microscopy, nitrogen adsorption, absorption spectroscopy in the infrared and thermal gravimetric analysis (TG / DTG).The study was conducted on the thermogravimetric behavior of sunflower oil on the mesoporous catalyst cited. Activation energy, conversion, and oil degradation as a function of temperature were estimated based on the integral curves of thermogravimetric analysis and the kinetic method of Vyazovkin. The mesoporous material Al-MCM-41 showed one-dimensional hexagonal formation. The study of the kinetic behavior of sunflower oil with the catalyst showed a lower activation energy against the activation energy of pure sunflower oil. Two liquid fractions of sunflower oil were obtained, both in thermal and thermocatalytic pyrolisis. The first fraction obtained was called bio-oil and the second fraction obtained was called acid fraction. The acid fraction collected, in thermal and thermocatalytic pyrolisis, showed very high level of acidity, which is why it was called acid fraction. The first fraction was collected bio-called because it presented results in the range similar to petroleum diesel / O uso dos biocombust?veis remota ao s?culo XVIII, quando Rudolf Diesel realizou os primeiros ensaios utilizando o ?leo de amendoim como combust?vel em um motor de igni??o por compress?o. Com base nesses ensaios, constatou-se a necessidade de realizar algumas transforma??es qu?micas ao ?leo vegetal. Dentre essas transforma??es qu?micas, pode-se citar a transesterifica??o e o craqueamento. Este trabalho tem como objetivo, realizar um estudo utilizando-se o craqueamento t?rmico e termocatal?tico do ?leo de girassol, utilizando o Al-MCM-41 como catalisador. O material mesoporoso tipo Al-MCM-41 foi sintetizado hidrotermicamente e caracterizado pelos m?todos de difra??o de raios-X, microscopia eletr?nica de varredura, adsor??o de nitrog?nio, espectroscopia de absor??o na regi?o do infravermelho e an?lise termogravim?trica (TG/DTG). Ainda foi realizado o estudo do comportamento termogravim?trico do ?leo de girassol sobre o catalisador mesoporoso citado. Com base nas curvas integrais das an?lises termogravim?tricas e o m?todo cin?tico de Vyazovkin, foram estimados a energia de ativa??o, a convers?o e a degrada??o do ?leo em fun??o da temperatura. O material mesoporoso Al-MCM-41 apresentou forma??o hexagonal unidimensional. O estudo do comportamento cin?tico do ?leo de girassol com o catalisador mostrou uma menor energia de ativa??o frente ? energia de ativa??o do ?leo de girassol puro. Na pir?lise t?rmica e termocatal?tica do ?leo de girassol foram obtidas duas fra??es l?quidas. A primeira fra??o obtida foi denominada de bio?leo e a segunda fra??o obtida foi denominada de fra??o ?cida. A fra??o ?cida coletada tanto na pir?lise t?rmica como na termocatal?tica apresentou ?ndice de acidez muito elevado, raz?o pela qual foi denominada fra??o ?cida. A primeira fra??o coletada foi denominada de bio?leo porque apresentou resultados na faixa semelhante ao diesel de petr?leo

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-30T22:35:16Z No. of bitstreams: 1 EnedersonRossetto_TESE.pdf: 3942346 bytes, checksum: 4f772d5bb76c7fedad3ac6471650a54d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-01T20:17:58Z (GMT) No. of bitstreams: 1 EnedersonRossetto_TESE.pdf: 3942346 bytes, checksum: 4f772d5bb76c7fedad3ac6471650a54d (MD5) / Made available in DSpace on 2016-06-01T20:17:58Z (GMT). No. of bitstreams: 1 EnedersonRossetto_TESE.pdf: 3942346 bytes, checksum: 4f772d5bb76c7fedad3ac6471650a54d (MD5) Previous issue date: 2015-07-31 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Os ligantes ?-diiminas 2-(fenil)amino-4-(fenil)imino-2-penteno e o 2-(2,6-dimetilfenil)amino-4-(2,6-dimetilfenil)imino-2-penteno foram combinados com o grupo alcoxisilano cloropropiltrimetoxisilano (CPTMS) e ancorado covalentemente aos suportes mesoporosos MCM-41 e SBA-15, coordenados pela intera??o com os grupos silan?is da matriz das s?licas e complexados com n?quel. Os complexos Ni-?-diimina/mesoporosos foram sintetizados para aplica??o em rea??es de oligomeriza??o do etileno e do propileno e para compara??o dos resultados entre o sistema homog?neo com o sistema heterog?neo. O suporte foi primeiramente sintetizado e calcinado. Ap?s foi realizado o ancoramento dos ligantes e posterior complexac?o do n?quel. Estes materiais foram caracterizados por v?rias t?cnicas, tais como: RMN de 1H, 13C e 29Si, DRX de baixo ?ngulo, Infra-vermelho (IR), an?lise termogravim?trica, an?lise de isotermas de adsor??o-dessor??o de N2, microscopia eletr?nica de transmiss?o (MET) e de varredura (MEV), an?lise elementar e espectroscopia de absor??o at?mica para confirmar o sucesso das s?nteses dos materiais. Ambos os complexos homog?neos e os heterogeneizados s?o ativos e seletivos para as rea??es de oligomeriza??o do etileno e do propileno. Os materiais heterogeneizados foram menos ativos que os complexos an?logos homog?neos nas rea??es de oligomeriza??o do etileno, por?m, foram mais seletivos tanto para fra??es C4 quanto para ?-C4. Nas rea??es com o propileno os complexos homog?neos promoveram ? rea??o de dimeriza??o e os complexos heterogeneizados ? rea??o de alquila??o do tolueno com o propileno. / The ?-diimine ligands 2-(phenyl)amine-4-(phenyl)imine-2-pentene and 2-(2,6- dimethylphenyl)amine-4-(2,6-dimethylphenyl)imine-2-pentene were combined with the alkoxysilane group chloropropyltrimethoxysilane (CPTMS) and covalently anchored to a mesoporous MCM-41, Al-MCM-41 and SBA-15 support, ordered by interaction with the silanols of the silica matrix and complexed with nickel. The complexes were synthesized for application in ethylene and propylene oligomerization and for comparing results between homogeneous and heterogeneous systems. The support is first synthesized, calcined, anchored to the ligand, and then subsequent complexation of nickel is realized. These materials were characterized by several techniques such as 1H, 13C and 29Si NMR, small angle XRD, Infra-red, thermogravimetric analysis, nitrogen adsorption-desorption isotherms, transmission and scanning electron microscopy, elemental analysis, and flame atomic absorption spectroscopy, to confirm the success of the synthesis. Both homogeneous and heterogeneous complexes are active and selective for the reactions of ethylene and propylene oligomerization. The heterogenized materials were less active than the homogeneous analogous complexes in the reactions of oligomerization of ethylene, however, were more selective for both C4 fractions and for ?-C4. In reactions with propylene, the homogeneous complexes promoted the dimerization reaction and the heterogenized complexes the alkylation reaction of toluene with propylene complex.Complexes were tested in recycle reactions proved to be efficient for use in large scale.

[pt] A síntese de Fischer-Tropsch converte o gás de síntese (H2 + CO), em uma variedade complexa de hidrocarbonetos na presença de um catalisador (principalmente Co/Al2O3). Neste trabalho foram estudados catalisadores de Co e o Fe (1 e 5% em massa), incorporados aos suportes: zeólitas KL, HL 0,1M e HL 1,0 M, além da peneira molecular mesoporosa MCM- 41, pelo método de impregnação úmida incipiente, para a reação de Fischer- Tropsch. As amostras preparadas foram analisadas pelas técnicas de: Espectometria de Emissão Atômica de Plasma Acoplado Induzido, Adsorção Física de N2 pelo método BET, Difração de Raios-X, Redução com Temperatura Programada, Microscopia Eletrônica de Transmissão (MET), Quimissorção de Hidrogênio e Espectroscopia no Infravermelho de piridina adsorvida. Além disso, as amostras foram avaliadas em um reator de leito fixo na reação de Fischer-Tropsch. Para as amostras de ferro, com mesmo teor e suportes diferentes, pode-se observar que a amostra suportada na MCM-41 apresentou um grau de redução menor. Entre as amostras de ferro suportadas na KL, a 5% Fe/KL apresentou maior grau de redução e foi observado por microscopia eletrônica de transmissão (MET) que as partículas de ferro apresentaram diâmetro em torno de 6 nm. Para as amostras de cobalto foi observado que a temperatura de redução da amostra suportada na MCM-41 foi mais alta. A amostra 5% Co/KL apresentou um maior grau de redução. Foi possível observar por MET que as partículas de cobalto apresentaram diâmetro variando entre 8 e 20 nm. Verificou-se que o catalisador com maior teor de ferro proporcionou uma maior conversão de CO, tendo sido a distribuição de produtos deslocada para as frações mais leves. Comparando os catalisadores de ferro suportados na zeólita KL e na MCM-41 pode-se concluir que as conversões são da mesma ordem de grandeza. Foi observado que o ferro foi mais ativo que o cobalto em termos de conversão do CO, sendo que o cobalto promoveu a formação de uma maior quantidade de produtos na faixa de diesel, assim como uma menor quantidade de leves. / [en] The Fischer- Tropsch synthesis converts the synthesis gas (H2 + CO), in a complex variety of hydrocarbons, using a catalyst (Co/Al2O3 normally) were introduced to the used supports by the wetness incipient impregnation. The samples were analyzed by several techniques such as: plasma- emission spectrometry (ICP- EAS), N2 physical adsorption by BET method, X-ray diffraction (XRD), temperature programmed reduction (TPR), transmission electronic microscopy (TEM), hydrogen chemisorption and Infrared Spectroscopy of adsorbed pyridine. The catalysts were evaluated using a fixed bed reactor in the Fischer-Tropsch synthesis. For the iron samples, with the same metal content and different supports, it was observed that the MCM-41 sample presented the lowest reduction level. Among the iron samples supported in KL zeolite, the 5% Fe/KL sample presented the largest reduction level. It was observed by transmission electronic microscopy that the iron particles diameter measured around 6 nm. For the cobalt samples, it was observed that the reduction temperature of the MCM-41 supported was the highest one. The 5% Co/KL sample presented the largest reduction level. It was observed by TEM that the cobalt particles presented diameters in the range from 8 to 20 nm. It was verified that the catalyst with the largest iron percentage promoved the highest CO conversion. The products distribuition was shifted to light fractions. It was observed similar conversions to iron catalysts supported in the KL zeolite and in the MCM- 41 mesoporous molecular sieve. The iron catalysts were more active than the cobalt ones in the CO conversion, but tha cobalt catalysts promoted a higher content of diesel fraction and lesser light fractions.

Made available in DSpace on 2014-12-17T15:41:53Z (GMT). No. of bitstreams: 1 JoseABLRA_DISSERT.pdf: 2347923 bytes, checksum: 6e0dcb6d004a500ef5b9305459cc4e95 (MD5) Previous issue date: 2010-05-27 / Mesoporous molecular sieves of MCM-41 type are considered as promising support for metal in the refining processes of petroleum-based materials as catalysts and adsorbents for environmental protection. In this work, mesoporous molecular sieves MCM-41 were modified with different rare earth ions (La, Eu e Yb) for the obtaining nanostrutured materials with catalytic properties. The catalysts were synthesized by the hydrothermal method at 100oC for 120 h, presenting, all the samples, in the gel of synthesis molar ratio Si/Ln = 50. The obtained materials after calcination at 500oC for 2 h were characterized by XRD, surface area BET, TG/DTG, FTIR, and hydrothermal stability at 700?C. The XRD analysis of the catalysts indicated that the materials containing rare earth presented characteristic hexagonal structure of the mesoporous materials of the type MCM-41. The TG curves showed that the decomposition of the structural template occurs in the materials at temperatures lower than 500oC. The samples presented variations as the specific superficial area, average diameter of pores and thickness of the silica wall, as a function of the nature of the rare earth impregnated in the mesoporous material. Hydrotermal stability was evaluated through the exposition of the materials to water vapour at 700?C. The thiophene adsorptions reach a maximum at 80% of conversion and incorporation of the rare earths showed influence in the process. Adsorption capacity followed the sequence: Yb-MCM-41 < La-MCM-41 < Eu-MCM-41 < MCM-41 / As peneiras moleculares mesoporosas do tipo MCM-41 s?o consideradas promissoras como suporte para metais em processos de refino de materiais a base de petr?leo, como catalisadores e como adsorventes para prote??o ambiental. Neste trabalho a peneira molecular mesoporosa tipo MCM-41 foi modificada com diferentes terras raras (La, Eu e Yb) para a obten??o de materiais nanoestruturados com propriedades catal?ticas. Os catalisadores foram sintetizados pelo m?todo hidrot?rmico a 100 oC por 120 horas, apresentando, todas as amostras, no gel de s?ntese raz?o molar Si/Ln = 50. Os materiais resultantes, ap?s calcina??o a 500 oC por 2 horas, foram caracterizados por: DRX, ?rea superficial pelo m?todo de BET, TG/DTG, FTIR e testes hidrot?rmicos a 700oC. As an?lises de DRX dos catalisadores indicaram que os materiais contendo as terras raras apresentaram estrutura hexagonal caracter?stica do material mesoporoso tipo MCM-41. As curvas TG mostraram que a decomposi??o do direcionador estrutural ocorre nos materiais em temperaturas inferiores a 500oC. As amostras apresentaram varia??es quanto ? ?rea superficial espec?fica, di?metro m?dio de poros e espessura da parede de s?lica, em fun??o da natureza da terra rara impregnada no material mesoporoso. A estabilidade hidrot?rmica foi avaliada atrav?s da exposi??o dos materiais a vapor d ?gua a 700oC. A adsor??o de tiofeno atingiu valores m?ximos de 80% e a incorpora??o das terras raras influenciaram no processo. A ordem crescente de capacidade de adsor??o seguiu a seguinte seq??ncia: Yb-MCM-41 < La-MCM-41 < Eu-MCM-41 < MCM-41

Made available in DSpace on 2014-12-17T15:42:09Z (GMT). No. of bitstreams: 1 AnaCRM_TESE.pdf: 3734770 bytes, checksum: 59720290841ee6807d60b116e21f2090 (MD5) Previous issue date: 2010-12-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Microporous materials zeolite type Beta and mesoporous type MCM-41 and AlMCM-41 were synthesized hydrothermally and characterized by methods of X-ray diffraction, Fourier transform infrared, scanning electron microscopy, surface acidity, nitrogen adsorption, thermal analysis TG / DTG. Also we performed a kinetic study of sunflower oil on micro and mesoporous catalysts. The microporous material zeolite beta showed a lower crystallinity due to the existence of smaller crystals and a larger number of structural defects. As for the mesoporous materials MCM-41 and AlMCM-41 samples showed formation of hexagonal one-dimensional structure. The study of kinetic behavior of sunflower oil with zeolite beta catalysts, AlMCM-41 and MCM-41 showed a lower activation energy in front of the energy of pure sunflower oil, mainly zeolite beta. In the thermal cracking and thermocatalytic of sunflower oil were obtained two liquid fractions containing an aqueous phase and another organic - organic liquid fraction (FLO). The FLO first collected in both the thermal cracking as the thermocatalytic, showed very high level of acidity, performed characterizations of physicochemical properties of the second fraction in accordance with the specifications of the ANP. The second FLO thermocatalytic collected in cracking of sunflower oil presented results in the range of diesel oil, introducing himself as a promising alternative for use as biofuel liquid similar to diesel, either instead or mixed with it / Os materiais microporosos tipo ze?lita beta e mesoporosos tipo MCM-41 e AlMCM-41 foram sintetizados hidrotermicamente e caracterizados pelos m?todos de difra??o de raios X, infravermelho por transformada de Fourier, microscopia eletr?nica de varredura, acidez superficial, adsor??o de nitrog?nio, an?lise t?rmica via TG/DTG. Ainda foi realizado um estudo do comportamento cin?tico termogravim?trico do ?leo de girassol sobre os catalisadores micro e mesoporosos citados. Usando curvas integrais da TG e o m?todo cin?tico de Vyazovkin, foram estimados a energia de ativa??o, as taxas de convers?o e o tempo degrada??o do ?leo em fun??o da temperatura. O material microporoso ze?lita beta apresentou menor cristalinidade, devido ? exist?ncia de cristais menores e um maior n?mero de defeitos estruturais. Quanto aos materiais mesoporosos MCM-41 e AlMCM-41 apresentaram amostras com forma??o da estrutura hexagonal unidimensional. O estudo do comportamento cin?tico do ?leo de girassol com os catalisadores ze?lita beta, AlMCM-41 e MCM-41, mostrou uma menor energia de ativa??o frente a energia do ?leo de girassol puro, principalmente a ze?lita beta. No craqueamento t?rmico e termocatal?tico do ?leo de girassol foram obtidas duas fra??es l?quidas contendo uma fase aquosa e outra org?nica fra??o l?quida org?nica (FLO). A primeira FLO coletada, tanto no craqueamento t?rmico quanto no termocatal?tico, apresentou ?ndice de acidez muito elevado, sendo assim foi realizada as caracteriza??es das propriedades f?sico-qu?micas da segunda fra??o de acordo com as especifica??es da ANP. As segundas FLOs coletadas no craqueamento termocatal?tico do ?leo de girassol apresentaram resultados na faixa adequada ao diesel de petr?leo, apresentando-se como uma alternativa promissora para utiliza??o como biocombust?vel l?quido similar ao diesel, seja em substitui??o, ou misturado a este