Este trabalho teve como objetivo investigar a adsorção de corantes têxteis (Vermelho Reativo 194 e Azul de Prociona MX-R) em nanotubos de carbono (NTC) em meio aquoso. Para tanto, empregou-se nanotubos de carbono de paredes múltiplas (NTCPM) e carvão ativo (CA) em pó, ambos comerciais, na remoção do corante têxtil Vermelho Reativo 194 e nanotubos de carbono de parede simples (NTCPS) e NTCPM na remoção do corante têxtil Azul de Prociona MX-R. Os NTCPS foram sintetizados utilizando a técnica de deposição química de vapor catalisada. Os adsorventes foram caracterizados por espectroscopia no infravermelho e Raman, isotermas de adsorção/dessorção de N2 e microscopia eletrônica de varredura e de transmissão. Os efeitos do pH, tempo de agitação e da temperatura na capacidade de adsorção foram investigados. O tempo de contato para obter equilíbrio a 298 K foi fixado em uma hora para o caso onde foi empregado o corante Vermelho Reativo 194 e três horas para o caso onde foi empregado o Azul de Prociona MX-R. A região de pH ácido (pH 2,0) foi favorável para as adsorções de ambos corantes. A energia de ativação do processo de adsorção foi avaliada nas temperaturas entre 298-323 K para os NTCPM e CA, na adsorção do corante Vermelho Reativo 194. O modelo cinético de ordem fracionária de Avrami foi o que melhor se ajustou aos dados experimentais do corante Vermelho Reativo 194 em comparação com os modelos cinéticos de adsorção de pseudo-primeira ordem e pseudo-segunda ordem. Por outro lado, o modelo cinético de ordem geral foi o que melhor se ajustou aos dados experimentais do corante Azul de Prociano MX-R, em comparação aos modelos de pseudo-primeira ordem e pseudo-segunda ordem. Tanto para o corante Vermelho Reativo 194, quanto para o corante Azul de Prociona MX-R, os dados de equilíbrio obedeceram ao modelo de isoterma de Liu. O cálculo dos parâmetros termodinâmicos de adsorção indicou que a adsorção de ambos ocorre de forma endotérmica, espontânea e favorável para todas as temperaturas investigadas. Adicionalmente, a magnitude da entalpia indica que a adsorção para os dois corantes se dá através de interação eletrostática. Isso pode ser confirmado por cálculos ab initio, baseados na teoria do funcional da densidade, implementados no código SIESTA, para a adsorção do Azul de Prociona MX-R e um NTCPS (8,0). / This work aimed to investigate the adsorption of textile dyes (Reactive Red M-2BE and Reactive Blue 4) on carbon nanotubes (CNT). To this purpose, multi-walled carbon nanotubes (MWCNT) and powdered activated carbon (AC), both commercial, were used in removal of textile dye Reactive Red M-2BE and single-wall carbon nanotubes (SWCNT) and MWCNT in the removal of textile dye Reactive Blue 4. The SWCNT were synthesized by catalytical chemical vapour deposition. The adsorbents were characterised by infrared and Raman spectroscopy, N2 adsorption/desorption isotherms and scanning and transmission electron microscopy. The effects of pH, shaking time and temperature on adsorption capacity were studied. The contact time to obtain equilibrium at 298 K was fixed at 1 hour for the case where the Reactive Red M-2BE dye was used and 3 hours for the case where the dye was used Reactive Blue 4. In the acidic pH region (pH 2.0), the adsorption of the both dyes were favourable. The activation energy of the adsorption process was evaluated from 298 to 323 K for MWCNT and AC, in the adsorption of the Reactive Red M-2BE dye. The Avrami fractional-order kinetic model provided the best fit to the experimental data of the Reactive Red M-2BE dye compared with pseudo-first-order or pseudo-second-order kinetic adsorption models. On the other hand, the general order kinetic model provided the best fit to the experimental data of the Reactive Blue 4 dye, compared with pseudo-first order and pseudo-second order kinetic adsorption models. For both the Reactive Red M-2BE and the Reactive Blue 4 dyes, the equilibrium data were best fitted to the Liu isotherm model. The calculation of the thermodynamic parameters of adsorption indicated that adsorption of both dyes by adsorbents occurs so endothermic, spontaneous and favorable for all temperatures studied. Additionally, the magnitude of enthalpy indicates that the adsorption process for both dyes occurs through electrostatic interaction. This can be confirmed by ab initio calculations based on density functional theory, implemented in the SIESTA code, for the adsorption of Reactive Blue 4 textile dye and a SWCNT (8.0).

Made available in DSpace on 2014-06-11T19:31:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-28Bitstream added on 2014-06-13T18:42:35Z : No. of bitstreams: 1 pedro_mam_dr_sjrp.pdf: 1284122 bytes, checksum: 45709686cf62bab3c06f4aeffcf8c502 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os objetivos deste trabalho foram analisar a influência do tipo e da quantidade de aditivos, além de diferentes métodos de secagem da polpa de maracujá em pó, nas isotermas, propriedades termodinâmicas de sorção e nos atributos de qualidade do produto obtido. No capítulo 1 descreve-se o efeito de diferentes aditivos - maltodextrina DE 10 e goma arábica - sobre as isotermas de sorção nas temperaturas de 20, 30, 40 e 50 ºC de polpa de maracujá em pó obtida por secagem a vácuo. O modelo de GAB se ajustou aos dados de sorção. As isotermas apresentaram comportamento da curva do tipo II, na classificação de Brunauer. Observou-se que a adição de maltodextrina DE 10 e de goma arábica à polpa de maracujá desidratada reduziu a umidade de equilíbrio em relação à umidade da polpa pura e não houve diferença considerável entre as umidades de equilíbrio das amostras da polpa com 18% de goma arábica e polpa com 18% ou 55% de maltodextrina. O aumento da concentração da maltodextrina não teve influência sobre os valores de umidade de equilíbrio. O calor isostérico de sorção da polpa em pó aumentou com o decréscimo da umidade, ao mesmo tempo em que apresentou menores valores para a polpa em pó com aditivos do que os observados para a polpa pura. Através da teoria da compensação isocinética, pode-se concluir que o processo de sorção de água pela polpa de maracujá em pó é um processo espontâneo e controlado pela entalpia para todas as amostras testadas. No capítulo 2 foi analisada a influência de três métodos de secagem: em estufa a vácuo (60 ºC), spray drying (140 ºC) e liofilização sobre as isotermas da polpa de maracujá em pó com 55% de maltodextrina DE 10. O pó produzido em spray dryer apresentou maior capacidade de sorção em relação aos pós desidratados em estufa a vácuo e em liofilizador. No capítulo 3 foi avaliada a influência... / The objectives of this work were to analyze the influence of type and quantity of additives, in addition to different drying methods, on the production of powdered passion fruit pulp, on its water sorption isotherms and on its themodynamical properties, as well as evaluating the quality attributes of the obtained product. Chapter 1 describes the effect of different additives - maltodextrin DE 10 and Arabic gum - on the sorption isotherms at temperatures of 20, 30, 40 e 50 ºC of passion fruit pulp powder obtained by vacuum drying. The sorption data were well adjusted by GAB model. The isotherms presented behavior of type II curves according to the Brunauer classification. The addition of maltodextrin DE 10 and Arabic gum to the passion fruit pulp powder decreased the equilibrium water content when compared to the pure powdered pulp and no considerable differences between the equilibrium moisture content of samples with 18% of arabic gum and with 18% or 55% of maltodextrin were observed. The increase in maltodextrin concentration did not affect the equilibrium water contents. The isosteric heat of sorption of the powdered pulp increased with decreasing water content, at the same time that lower values were obtained to powdered pulp with additives than to pure powdered pulp. Through the isokinetic compensation theory it could be concluded that the water sorption process by the powdered passion fruit pulp is an enthalpy controlled, spontaneous process for all tested samples. In chapter II, the influence of three drying methods: vacuum drying (60 ºC), spray drying (140 ºC) and freeze drying over the powdered passion fruit pulp isotherms with 55% of maltodextrin DE 10, was analyzed. The passion fruit pulp powder produced by spray drying presented higher sorption ability than vacuum dried and freeze dried pulp. In chapter 3, the influence of different concentrations and different dextrose... (Complete abstract click electronic access below)

Este trabalho teve como objetivo investigar a adsorção de corantes têxteis (Vermelho Reativo 194 e Azul de Prociona MX-R) em nanotubos de carbono (NTC) em meio aquoso. Para tanto, empregou-se nanotubos de carbono de paredes múltiplas (NTCPM) e carvão ativo (CA) em pó, ambos comerciais, na remoção do corante têxtil Vermelho Reativo 194 e nanotubos de carbono de parede simples (NTCPS) e NTCPM na remoção do corante têxtil Azul de Prociona MX-R. Os NTCPS foram sintetizados utilizando a técnica de deposição química de vapor catalisada. Os adsorventes foram caracterizados por espectroscopia no infravermelho e Raman, isotermas de adsorção/dessorção de N2 e microscopia eletrônica de varredura e de transmissão. Os efeitos do pH, tempo de agitação e da temperatura na capacidade de adsorção foram investigados. O tempo de contato para obter equilíbrio a 298 K foi fixado em uma hora para o caso onde foi empregado o corante Vermelho Reativo 194 e três horas para o caso onde foi empregado o Azul de Prociona MX-R. A região de pH ácido (pH 2,0) foi favorável para as adsorções de ambos corantes. A energia de ativação do processo de adsorção foi avaliada nas temperaturas entre 298-323 K para os NTCPM e CA, na adsorção do corante Vermelho Reativo 194. O modelo cinético de ordem fracionária de Avrami foi o que melhor se ajustou aos dados experimentais do corante Vermelho Reativo 194 em comparação com os modelos cinéticos de adsorção de pseudo-primeira ordem e pseudo-segunda ordem. Por outro lado, o modelo cinético de ordem geral foi o que melhor se ajustou aos dados experimentais do corante Azul de Prociano MX-R, em comparação aos modelos de pseudo-primeira ordem e pseudo-segunda ordem. Tanto para o corante Vermelho Reativo 194, quanto para o corante Azul de Prociona MX-R, os dados de equilíbrio obedeceram ao modelo de isoterma de Liu. O cálculo dos parâmetros termodinâmicos de adsorção indicou que a adsorção de ambos ocorre de forma endotérmica, espontânea e favorável para todas as temperaturas investigadas. Adicionalmente, a magnitude da entalpia indica que a adsorção para os dois corantes se dá através de interação eletrostática. Isso pode ser confirmado por cálculos ab initio, baseados na teoria do funcional da densidade, implementados no código SIESTA, para a adsorção do Azul de Prociona MX-R e um NTCPS (8,0). / This work aimed to investigate the adsorption of textile dyes (Reactive Red M-2BE and Reactive Blue 4) on carbon nanotubes (CNT). To this purpose, multi-walled carbon nanotubes (MWCNT) and powdered activated carbon (AC), both commercial, were used in removal of textile dye Reactive Red M-2BE and single-wall carbon nanotubes (SWCNT) and MWCNT in the removal of textile dye Reactive Blue 4. The SWCNT were synthesized by catalytical chemical vapour deposition. The adsorbents were characterised by infrared and Raman spectroscopy, N2 adsorption/desorption isotherms and scanning and transmission electron microscopy. The effects of pH, shaking time and temperature on adsorption capacity were studied. The contact time to obtain equilibrium at 298 K was fixed at 1 hour for the case where the Reactive Red M-2BE dye was used and 3 hours for the case where the dye was used Reactive Blue 4. In the acidic pH region (pH 2.0), the adsorption of the both dyes were favourable. The activation energy of the adsorption process was evaluated from 298 to 323 K for MWCNT and AC, in the adsorption of the Reactive Red M-2BE dye. The Avrami fractional-order kinetic model provided the best fit to the experimental data of the Reactive Red M-2BE dye compared with pseudo-first-order or pseudo-second-order kinetic adsorption models. On the other hand, the general order kinetic model provided the best fit to the experimental data of the Reactive Blue 4 dye, compared with pseudo-first order and pseudo-second order kinetic adsorption models. For both the Reactive Red M-2BE and the Reactive Blue 4 dyes, the equilibrium data were best fitted to the Liu isotherm model. The calculation of the thermodynamic parameters of adsorption indicated that adsorption of both dyes by adsorbents occurs so endothermic, spontaneous and favorable for all temperatures studied. Additionally, the magnitude of enthalpy indicates that the adsorption process for both dyes occurs through electrostatic interaction. This can be confirmed by ab initio calculations based on density functional theory, implemented in the SIESTA code, for the adsorption of Reactive Blue 4 textile dye and a SWCNT (8.0).

Atualmente, o tipo de propelente para produtos em aerossol mais usado no mundo é uma mistura de hidrocarbonetos leves (butano e propano - sendo o primeiro em maior proporção). Parte de seu processo de produção é a dessulfurização do butano líquido, através de adsorção em leito fixo usando peneiras moleculares 13X. A literatura científica não apresenta muitas publicações sobre o tema e considerando que a técnica de adsorção é fortemente dependente de dados experimentais para seu maior entendimento, é objetivo deste trabalho estudar este processo através do equilíbrio de adsorção, das curvas de ruptura e do desenvolvimento de um modelo matemático que represente o funcionamento de uma coluna de adsorção de leito fixo a temperatura constante. Obtiveram-se dados sobre o equilíbrio de adsorção por meio de ensaios em banho finito comparando-se a interação de diferentes compostos de enxofre com a peneira molecular 13X e o efeito da temperatura. Utilizou-se a técnica de cromatografia gasosa como método analítico para obtenção dos teores de compostos sulfurados e de hidrocarbonetos. O modelo de Langmuir apresentou bom ajuste aos dados experimentais. Avaliando-se a interação dos componentes sulfurados com a zeólita 13X, identificou-se diferenças significativas, sendo a maior em ordem decrescente: etil-mercaptana, n-propil-mercaptana e terc-butil-mercaptana, respectivamente. A dinâmica do processo de adsorção foi estudada através da obtenção das curvas de ruptura em leitos em escala laboratorial e piloto. Avaliaram-se as influências da variação da concentração de entrada da n-propil-mercaptana e da velocidade do fluido em leito fixo recheado com zeólitas 13X, mantendo os demais parâmetros constantes. Conforme esperado o aumento da concentração inicial reduz o tempo de ruptura, aumenta a quantidade total adsorvida pelo leito e não altera o comportamento da zona de transferência de massa (ZTM). Analisando-se a elevação da velocidade, nota-se também uma diminuição no tempo de ruptura e um aumento da ZTM. O modelo matemático apresentado considera os balanços de massa microscópicos aplicados ao leito, os fenômenos de transporte de massa com modelo de dispersão axial e transporte por convecção da fase líquida para a superfície da partícula e as isotermas de adsorção. As equações diferenciais parciais resultantes foram adimensionalizadas e resolvidas empregando-se o método de diferenças finitas, implementado por código Matlab®. A partir da simulação matemática das condições experimentais obtiveram-se os parâmetros de dispersão axial e de transferência de massa que possibilitaram uma boa reprodução do tempo de ruptura quanto do perfil da zona de transferência de massa para os experimentos em escala laboratorial e piloto. / Currently, the kind of propellant for aerosol products most widely used in the world is a blend of light hydrocarbons (butane and propane - the first in greater proportion). Part of the production of propellant is the desulfurization of liquid-phase butane by molecular sieves 13X in a fixed bed. The scientific literature concerning the adsorption of the mercaptans using zeolite are scarce and considering that the adsorption technique is strongly dependent on experimental data for its better knowlegde, the aim of this work was to study this process by adsorption equilibrium, the breakthrough curves and the development of a mathematic model, simulation and comparison with the operation of a fixed-bed pilot and laboratory-scale column. Adsorption equilibrium parameters were obtained using finite bath experiment and comparing the interaction of different sulfur compounds with molecular sieve 13X and the temperature effect. It was used the gas chromatography as an analytical method in order to obtain the levels of hydrocarbons and sulfur compounds. The Langmuir model well fit the experimental data. Significant differences were identified in the interaction of the sulfur components with zeolite 13X. The major interactions of the sulfur components are in decreasing order: ethyl-mercaptan, n-propyl-mercaptan and terc-butyl-mercaptan. The dynamic of the adsorption process was studied by obtaining the breakthrough curves in laboratory and pilot scale. It was investigated the influence of the initial concentration of n-propyl mercaptan and the fluid velocity in a fixed bed packed with zeolite 13X keeping the other parameters constant. As it was expected, as the inlet sulfur concentration increases the break point time decrease, and enhances the total amount adsorbed by the bed. Analyzing the increase in velocity on the breakthroug profile, it was noted that also decreases the break point time and causes a greater decline of the curve resulting in greater ZTM and anticipating the bed saturation time. The model equations account the mass balance applied in the flowing liquid phase in the column, transport phenomena as the effect of axial dispersion and convection from liquid phase to the adsorbent surface and adsorption isotherm. Finite difference method was used to solve the dimensionless general partial differential equations and it was implemented by Matlab® software. From mathematical simulation of experimental conditions it were obtained the axial dispersion parameters and mass transfer coefficient which allowed a fair agreement in predicting break point time and the mass transfer zone profile.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / The tururi and buriti fibers, and the castor bean stalks are extremely efficient to sorption of metal ions from aqueous solutions. In this study, the adsorbents were activated with different concentrations of alkali solutions (5, 7, 10 and 15% w/v). The materials were characterized by analytical techniques as infrared, X-ray Diffraction (XRD) and Thermogravimetry analysis. The infrared spectra revealed that associated groups to macromolecules of hemicellulose and lignin after alkaline activation have less intensity compared to the initial samples. The XRD revealed, that after castor bean stalks alkaline activation, the presence of the cellulose type II peaks, which did not occur with tururi and buriti fibers. The fluorescence X-ray data showed that the cations present in the initial adsorbents, K+ and Ca2 + are exchanged by Cu (II), Ni (II), Cd (II) and Pb (II) in the sorption process. Studies of the influences of variables: mass of adsorbent; agitation rate; the initial pH and concentration using a fractional factorial design 24-1 demonstrated that all variables affect the response (adsorption capacity mg g-1). As a result for a larger value of qtotal, conditions were observed while maintaining the pH at 5.5; mass of the adsorbent 50 mg; agitation at 200 rpm and the initial concentration: 500 mg L-1. The adsorption kinetics revealed fast adsorption process, about 30 minutes, and good fitting to pseudo-second-order theoretical model to all adsorption process studied. Intraparticle diffusion models as Weber-Morris and Boyd were testes in order to study the limiting steps of the process.The results showed that for tururi and buriti fibers (with the exception of nickel ions) the rate-limiting step is not the intraparticle diffusion, while for the castor bean stalks, it was found that the rate-limiting step of the process is the intraparticle diffusion. The study of monoelement and multielement systems were performed at pH 5.5, initial concentrations from 20-500 mg L-1, which the experimental data were fitted to the Langmuir, Freundlich and Sips theoretical models. The tururi fibers adsorption capacities (mg g-1) in monoelementar and multielement system follows the order Pb (188.79)> Cd (92.20)> Cu (32.82)> Ni (22.23) and Cd (77.53)> Pb (43.93)> Cu (24.99)> Ni (19.51), respectively. Buriti fibers adsorption capacities (g-1 mg) in monoelementar and multielement systems follows the order of Cu (143.1)> Pb (112.1)> Ni (103.7)> Cd (86.33) and Pb (69.12)> Cu (49.28)> Ni (45.10)> Cd (24.95), respectively. Castor bean stalks adsorption capacities (g-1 mg) in in monoelementar and multielement systems follows the order of Pb (175.1)> Cd (124.8)> Ni (111.1)> Cu (89.23) and Cu (56.78)> Pb (55.82)> Cd (44.72)> Ni (43.48), respectively. The results showed a better fit for the Sips model, relating to a heterogeneous adsorption. Fixed bed studies using castor bean stalks checking the influence of variables adsorbent flow (1, 2 and 3 mL min-1), the height of the column (5, 7 and 10 cm) and initial concentration (100 , 200, 300 mg L-1) by the Box-Behnken planning revealed that there were no influence between the variables in the studied. The breakthrough curves were well fitted to the Thomas model. The study in real effluent with Cu (II) (galvanoplastic sector) was carried out using the optimized condition: flow (1 ml min-1); bed height (10 cm) initial concentration: (245.5 mg L-1) and it was found adsorption capacity of 32.42 mg g-1. The mamoneira stalks adsorbent was used for five cycles to verify their potential reuse, and it was found no significant efficiency losses. / As fibras tururi, buriti e talos da mamoneira sÃo resÃduos lignocelulÃsicos extremamente eficientes na sorÃÃo de metais de soluÃÃes aquosas. Neste trabalho, eles foram ativados com diferentes concentraÃÃes de soluÃÃes alcalinas (5, 7, 10 e 15% m/v). Os materiais foram caracterizados pelas tÃcnicas analÃticas de Infravermelho, DifraÃÃo de Raios-X (DRX) e Termogravimetria. Os espectros de infravermelho revelaram que os grupos associados Ãs macromolÃculas de hemicelulose e lignina diminuem em intensidade ou desaparecem apÃs a ativaÃÃo alcalina. Os DRX revelaram que apÃs a ativaÃÃo alcalina, os talos da mamoneira apresentaram picos de celulose tipo II, o que nÃo ocorreu com as fibras de tururi e buriti. O dados de FluorescÃncia de Raios-X revelaram que os cÃtions presentes nos adsorventes como Na(I) e Ca(II) sÃo trocados pelos Ãons Cu(II), Ni(II), Cd(II) e Pb(II) no processo de sorÃÃo. Os estudos das influÃncias das variÃveis: massa do adsorvente; taxa de agitaÃÃo; pH e concentraÃÃo inicial utilizando planejamento experimental fracionÃrio 24-1 demostrou que todas as variÃveis afetaram a resposta (capacidade de adsorÃÃo mg g-1). Como resultado para um maior valor de qtotal, as condiÃÃes observadas foram mantendo o pH em 5,5; massa do adsorvente em 50 mg; taxa de agitaÃÃo em 200 rpm e concentraÃÃo inicial 500 mg L-1. A cinÃtica de adsorÃÃo revelou rÃpida adsorÃÃo, cerca de 30 minutos em geral, seguindo o modelo de pseudo-segunda ordem em todos os processos adsortivos. Modelos de difusÃo intrapartÃcula como de Webber-Morris e Boyd foram estudados a fim de determinar as etapas limitantes do processo. Os dados evidenciaram que para as fibras de tururi e buriti (com exceÃÃo dos Ãons nÃquel) a etapa limitante da velocidade nÃo à a difusÃo intraporo, enquanto para os talos de mamoneira foi verificado que a etapa limitante do processo à a difusÃo intrapartÃcula. O estudo com sistema monoelementar e multielementar foi realizado em pH 5,5, concentraÃÃes variando de 20-500 mg L-1, nos quais os dados foram aplicados aos modelos de Langmuir, Freundlich e Sips. As capacidades de adsorÃÃo (mg g-1) em sistema monoelementar e multielementar das fibras de tururi segue a ordem Pb(188,79)> Cd(92,20)> Cu(32,82)> Ni(22,23) e Cd(77,53)> Pb(43,93)> Cu(24,99)> Ni(19,51), respectivamente. As capacidades de adsorÃÃo (mg g-1) das fibras de buriti em sistema monoelementar e multielementar segue a ordem Cu(143,1)> Pb(112,1)> Ni(103,7) > Cd(86,33) e Pb(69,12)> Cu(49,28)> Ni(45,10)> Cd(24,95), respectivamente. As capacidades de adsorÃÃo (mg g-1) dos talos de mamoneira em sistema monoelementar e multielementar segue a ordem Pb(175,1)> Cd(124,8)> Ni(111,1)> Cu(89,23) e Cu(56,78)> Pb(55,82)> Cd(44,72)> Ni(43,48), respectivamente. Em geral, os resultados evidenciaram melhor aplicabilidade ao modelo de Sips, o qual prediz que os sÃtios disponÃveis para adsorÃÃo sÃo heterogÃneos. Em relaÃÃo ao estudo de adsorÃÃo em leito fixo utilizando talos de mamoneira, a verificaÃÃo da influÃncia das variÃveis: fluxo do adsorvente (1, 2 e 3mL min-1), altura da coluna (5, 7 e 10 cm) e concentraÃÃo inicial (100, 200, 300 mg L-1) pelo planejamento de Box-Behnken, revelou que nÃo hà influencia mutua entre as variÃveis no intervalo estudado. As curvas de ruptura experimentais foram bem aplicadas ao modelo teÃrico de Thomas. O estudo com efluente real de Ãons Cu (II) (setor galvanoplÃstico) utilizando a condiÃÃo otimizada: fluxo (1mL min-1); altura de leito (10 cm) e concentraÃÃo inicial: (245,5 mg L-1) obteve 32,42 mg g-1 de capacidade de adsorÃÃo O adsorvente talos de mamoneira foi utilizado por cinco ciclos para verificar seu potencial de uso, nÃo havendo perdas significativas de eficiÃncia.

Este trabalho teve como objetivo investigar a adsorção de corantes têxteis (Vermelho Reativo 194 e Azul de Prociona MX-R) em nanotubos de carbono (NTC) em meio aquoso. Para tanto, empregou-se nanotubos de carbono de paredes múltiplas (NTCPM) e carvão ativo (CA) em pó, ambos comerciais, na remoção do corante têxtil Vermelho Reativo 194 e nanotubos de carbono de parede simples (NTCPS) e NTCPM na remoção do corante têxtil Azul de Prociona MX-R. Os NTCPS foram sintetizados utilizando a técnica de deposição química de vapor catalisada. Os adsorventes foram caracterizados por espectroscopia no infravermelho e Raman, isotermas de adsorção/dessorção de N2 e microscopia eletrônica de varredura e de transmissão. Os efeitos do pH, tempo de agitação e da temperatura na capacidade de adsorção foram investigados. O tempo de contato para obter equilíbrio a 298 K foi fixado em uma hora para o caso onde foi empregado o corante Vermelho Reativo 194 e três horas para o caso onde foi empregado o Azul de Prociona MX-R. A região de pH ácido (pH 2,0) foi favorável para as adsorções de ambos corantes. A energia de ativação do processo de adsorção foi avaliada nas temperaturas entre 298-323 K para os NTCPM e CA, na adsorção do corante Vermelho Reativo 194. O modelo cinético de ordem fracionária de Avrami foi o que melhor se ajustou aos dados experimentais do corante Vermelho Reativo 194 em comparação com os modelos cinéticos de adsorção de pseudo-primeira ordem e pseudo-segunda ordem. Por outro lado, o modelo cinético de ordem geral foi o que melhor se ajustou aos dados experimentais do corante Azul de Prociano MX-R, em comparação aos modelos de pseudo-primeira ordem e pseudo-segunda ordem. Tanto para o corante Vermelho Reativo 194, quanto para o corante Azul de Prociona MX-R, os dados de equilíbrio obedeceram ao modelo de isoterma de Liu. O cálculo dos parâmetros termodinâmicos de adsorção indicou que a adsorção de ambos ocorre de forma endotérmica, espontânea e favorável para todas as temperaturas investigadas. Adicionalmente, a magnitude da entalpia indica que a adsorção para os dois corantes se dá através de interação eletrostática. Isso pode ser confirmado por cálculos ab initio, baseados na teoria do funcional da densidade, implementados no código SIESTA, para a adsorção do Azul de Prociona MX-R e um NTCPS (8,0). / This work aimed to investigate the adsorption of textile dyes (Reactive Red M-2BE and Reactive Blue 4) on carbon nanotubes (CNT). To this purpose, multi-walled carbon nanotubes (MWCNT) and powdered activated carbon (AC), both commercial, were used in removal of textile dye Reactive Red M-2BE and single-wall carbon nanotubes (SWCNT) and MWCNT in the removal of textile dye Reactive Blue 4. The SWCNT were synthesized by catalytical chemical vapour deposition. The adsorbents were characterised by infrared and Raman spectroscopy, N2 adsorption/desorption isotherms and scanning and transmission electron microscopy. The effects of pH, shaking time and temperature on adsorption capacity were studied. The contact time to obtain equilibrium at 298 K was fixed at 1 hour for the case where the Reactive Red M-2BE dye was used and 3 hours for the case where the dye was used Reactive Blue 4. In the acidic pH region (pH 2.0), the adsorption of the both dyes were favourable. The activation energy of the adsorption process was evaluated from 298 to 323 K for MWCNT and AC, in the adsorption of the Reactive Red M-2BE dye. The Avrami fractional-order kinetic model provided the best fit to the experimental data of the Reactive Red M-2BE dye compared with pseudo-first-order or pseudo-second-order kinetic adsorption models. On the other hand, the general order kinetic model provided the best fit to the experimental data of the Reactive Blue 4 dye, compared with pseudo-first order and pseudo-second order kinetic adsorption models. For both the Reactive Red M-2BE and the Reactive Blue 4 dyes, the equilibrium data were best fitted to the Liu isotherm model. The calculation of the thermodynamic parameters of adsorption indicated that adsorption of both dyes by adsorbents occurs so endothermic, spontaneous and favorable for all temperatures studied. Additionally, the magnitude of enthalpy indicates that the adsorption process for both dyes occurs through electrostatic interaction. This can be confirmed by ab initio calculations based on density functional theory, implemented in the SIESTA code, for the adsorption of Reactive Blue 4 textile dye and a SWCNT (8.0).

Ce travail de thèse a été réalisé, dans le cadre de la convention CIFRE 1538/2010, au sein d'adixen Vacuum Products (aVP) à Annecy (France). Il a été en partie financé par le projet S.P.A.M. (Surface Physics for Advanced Manufacturing). Il s'agit d'un projet ITN financé par le programme Pierre et Marie Curie de la Communauté Européenne rassemblant des partenaires universitaires et industriels dont aVP. L'objectif de ce programme était de contribuer à l'étude et au développement de la lithographie et en particulier la lithographie à ultraviolet extrême (EUVL). Ce travail porte sur la problématique de la contamination moléculaire dans l'industrie des semi-conducteurs ainsi que les besoins de maitrise de contamination pour la photolithographie EUVL. Pour ce faire, des modèles mathématiques de sorption ont été recherchés, testés et validés à l'aide d'une microbalance à quartz (QCM). Cette technique, possédant une très haute sensibilité (au niveau du ng), permet d'étudier les phénomènes de sorption relatifs à tout matériau déposable sur un cristal de quartz mis au contact de différents gaz dont la pression partielle est maitrisée. Par conséquent, le protocole détaillé dans cette thèse peut être utilisé pour d'autres types d'expériences dans toute discipline nécessitant une telle précision. Le déroulement de notre plan d'expérience comprend deux types de matériaux naturellement différents : un polymère (PCBA) d'une part et deux substrats métalliques (SS AISI 304 et CuC1) d'autre part pour lesquels le transfert de masse n'intervient pas de la même manière. Les gaz d'étude ont été sélectionnés pour leur intérêt dans l'industrie des semi-conducteurs (vapeur d'eau, HF). Le résultat de l'interaction des gaz d'étude avec les substrats ciblés est suivi en direct par la QCM, ce qui permet non seulement de valider et/ou améliorer les modèles mathématiques déjà disponibles dans la bibliographie mais aussi de les ajuster aux données obtenues expérimentalement. Nous pouvons ainsi non seulement prévoir le comportement des contaminants à l'équilibre (isothermes) et à l'état transitoire mais aussi réaliser des estimations de sorption à des températures autres que celles retenues pour notre plan d'expérience / This thesis was carried out within the framework of the CIFRE 1538/2010 convention at adixen Vacuum Products (aVP) in Annecy (France). It is has been partly funded by the ITN project SPAM (Surface Physics for Advanced Manufacturing). SPAM is an ITN project funded by the Pierre and Marie Curie program of the European Community bringing together academic institutions and industrial partners including aVP. The objective of this program was to contribute to the study and development of lithography and extreme ultraviolet lithography (EUVL). This work deals with the issues caused by the airborne molecular contamination (AMC) in the semiconductor industry and their control needs in EUVL and the current photolithography. In order to tackle the problem, sorption mathematical models have been investigated and validated using a quartz crystal microbalance (QCM). This technique, which confers a high sensitivity (ng level), allows the study of the sorption phenomena related to any deposable material onto a quartz crystal in contact with different gases whose concentrations are accurately controlled. Consequently, the protocol detailed in this thesis may be used for other types of experiments in any discipline requiring such precision. The conduct of our experimental plan includes two types of naturally different materials: a polymer (PCBA) on the one hand and two metallic substrates (stainless steel AISI 304 and CuC1) on the other hand, for which the matter transfer does not occur in the same manner. Studied gases were selected for their interest in the semiconductor industry (water vapor, HF). The resulting interaction between the studied gases and the targeted substrates is continuously followed by the QCM, which allows not only to validate the mathematical models already proposed by the literature but also to fit the experimentally obtained data. This enables us not only to predict the behavior of the AMC at equilibrium (isotherms) and the transient state but also to provide sorption estimations at temperatures other than those specified in our experimental plan

This study aims at tackling some of the problems often encountered in photostability testing and liquid formulation development. Three anti-cancer drugs will be employed as models; Dacarbazine (DBZ) has well established photostability issues, Axitinib (AXI) and Sunitinib (SUT) are two new drugs only commercially available in solid dosage forms. In ethanol, the photokinetics of these drugs were well described by the newly proposed Φ-order kinetic mathematical model. This has confirmed the photoreversible character of AXI and SUT’s and unimolecular photoreaction of DBZ’s photodegradations. Also, the Φ-order kinetics is proven to describe them better than the usually used classic thermal reaction orders. In aqueous solution, the drugs were found to undergo thermal and photochemical complex degradations, involving at least 3 photoproducts. A new photokinetic approach has been proposed in this work to solving and unravelling the attributes of such complex mechanisms. For the first time, the quantum yields (QY) of the three drugs were determined and found to increase with irradiation wavelength. SUT’s QY were comparable in ethanol and water (QY460 = 0.02), DBZ was found to be more photoefficient in water (QY330 = 0.04 and 0.1, respectively) and AXI in water (QY330 = 0.06 and 0.03). Φ-order kinetics’ potential for the development of reliable actinometers of the three drugs, without prior knowledge of unknown reaction parameters, has also been established. A general equation to describe the isotherm of a (Gn:Hm) guest-host multicomponent complex was proposed in this work to palliate the lack of a strategy for characterising nanosponge-drug complexes. It provides information on both stiochiometry and association constant of the complex. The results indicate that hydrophobic AXI forms a 1:0.8 complex, indicating the possibility of multiple association sites and/or different types of binding. The newly developed AXI/nanosponge liquid formulation has significantly increased solubility (5000-fold) and thermal stability. Furthermore, the photostability of DBZ and SUT were considerably improved by using a strategy based on light-absorption competitors. Their initial velocities reduced from 10 and 3 s-1 (respectively) to 1 and 0.13 s-1. The successful application of these methods to the model anti-cancer drugs has set out new approaches that might be found useful for future treatments of photodegradation data, development of drug-actinometers and liquid formulations of drugs.

Magister Scientiae - MSc / Energy is one of the basic needs of human beings and is extremely crucial for continued development of human life. Our work, leisure and our economic, social and physical welfare all depend on the sufficient, uninterrupted supply of energy. Therefore, it is essential to provide adequate and affordable energy for improving human welfare and raising living standards. Global concern over environmental climate change linked to fossil fuel consumption has increased pressure to generate power from renewable sources [1]. Although substantial advances in renewable energy technologies have been made, significant challenges remain in developing integrated renewable energy systems due primarily to mismatch between load demand and source capabilities [2]. The output from renewable energy sources such as photo-voltaic, wind, tidal, and micro-hydro fluctuate on an hourly, daily, and seasonal basis. As a result, these devices are not well suited for directly powering loads that require a uniform and uninterrupted supply of input energy. / South Africa

Le stockage géologique du CO2 dans des réservoirs aquifères de type calcaire et grès, du charbon non exploité est une des solutions envisagées pour réduire les émissions de gaz à effet de serre dans l’atmosphère. Cependant, l’injection de CO2 peut perturber les propriétés pétrophysiques (porosité et perméabilité), minéralogiques (transformations) et mécaniques (déformations, résistance à la rupture) des roches réservoir (calcaire, grès, charbon). Dans le cas du charbon, l’injection de CO2 peut également se traduire par des phénomènes de gonflement de la matrice liés au processus d’adsorption. L’objectif de ce travail de thèse est de traduire en termes de modèles phénoménologiques les comportements et les couplages chimio-poromécaniques des roches réservoir de type charbon. Dans ce travail, nous nous sommes focalisés en particulier sur l’étude de l’injection de CO2 dans le charbon. Pour cela, deux modèles homogénéisés de porosité du charbon ont été développés avec la prise en compte du phénomène d’adsorption, connu pour être le principal mécanisme de production ou de séquestration de CO2 dans de nombreux réservoir de charbon. Le premier modèle permet d’étudier le comportement poro-élastique du charbon pour une injection simple de CO2 et le second permet d’étudier le comportement poro-élastique du charbon pour une injection de CO2 avec une récupération assistée de méthane CH4. Le processus d’adsorption est classiquement modélisé à l’aide de l’isotherme d’adsorption de Langmuir (pour un gaz dans le premier modèle et pour deux gaz dans le second modèle). L’implantation de ces modèles dans le Code_Aster (code d’analyse de calcul de structures entièrement couplé THM, développé par Electricité De France - EDF) nous a permis de faire des simulations numériques de stockage de CO2 dans le charbon. Pour une injection simple du CO2 dans le charbon (premier modèle), la matrice du charbon s’est comportée de deux façons différentes : elle gonfle (ce qui induit une diminution de la porosité du charbon) avec la prise en compte du phénomène d’adsorption et se contracte (ce qui induit une augmentation de la porosité du charbon) dans le cas contraire. Etant en bon accord avec les résultats de la littérature spécialisée, cela montre la capacité du modèle à prédire le comportement poro-élastique du charbon durant l’injection de CO2. Toujours avec le premier modèle, nous avons en particulier étudié l’influence des propriétés hydro-mécaniques du charbon (coefficient de Biot, module de Young/module d’incompressibilité), les paramètres d’adsorption de Langmuir et la pression initiale du liquide interstitiel dans le charbon, sur la réponse du charbon à l’injection du CO2. Dans le cas d’une récupération assistée du méthane CH4 (le second modèle), un couplage du Code_Aster et un code de transport réactif HYTEC (HYdrological Transport coupled with Equilibrium Chemistry, développé par MINES Paris Tech) était nécessaire pour gérer surtout le calcul des pressions partielles des deux gaz (CO2 et CH4) à chaque pas de temps. Un travail de développement numérique sur les deux codes de calcul était alors nécessaire. Ce travail de thèse a proposé une méthode de couplage entre les deux codes (Code_Aster et HYTEC) dont les techniques sont largement décrites dans le manuscrit. / The geological storage of CO2 in aquifers reservoirs such as limestone and sandstone, coal is a possible way to reduce greenhouse gas emission into the atmosphere. However, the injection of CO2 may modify petrophysical (porosity and permeability), mineralogical (transformations) and mechanical (deformations, strength) properties of reservoir rocks (limestone, sandstone, coal). In the case of coal, the injection of CO2 can also induce matrix swelling due to adsorption processes. The focus of this thesis is to translate in terms of phenomenological models, the behaviors and chemo-poromechanical coupling of reservoir rocks of coal type. In this work, we focused particularly on the study of CO2 injection into coal. For this, two models of homogenized coal porosity have been developed by taking into account the adsorption phenomenon, known to be the main mechanism of production or sequestration of CO2 in many coal reservoirs. The first model allows the study of the poroelastic behavior of coal in the case of a single injection of CO2, and the second model allows the study of the poroelastic behavior of coal in the case of an injection of CO2 with methane CH4 recovery. The adsorption process is classically modelled using Langmuir’s isotherm (for one gas in the first model and for two gases in the second model). The implementation of these models in Code_Aster (a fully coupled Thermo-Hydro-Mechanical analysis code for structures calculations, developed by Electricity of France - EDF) allowed us to make numerical simulations of CO2 storage in coal. For a single injection of CO2 into coal (first model), the coal matrix behaved in two different ways: it swells (resulting in the decrease of coal porosity) when the adsorption phenomenon is taken into account and shrinks (resulting in the increase of coal porosity) otherwise. Being in good agreement with the results in specialized literature in this field, it shows the ability of the model to predict the poroelastic behaviour of coal to CO2 injection. Also with the first model, we studied particularly through numerical simulations the influence of coal’s hydro-mechanical properties (Biot’s coefficient, bulk modulus), Langmuir’s adsorption parameters and the initial liquid pressure in rock mass during CO2 injection in coal. In the case of methane recovery (second model), a coupling of Code_Aster and a reactive transport code, HYTEC (Hydrological Transport coupled with Equilibrium Chemistry, developed by Mines Paris Tech) was needed to handle the above calculation of partial pressures of the two gases (CO2 and CH4) at each time step. Digital development work on the two computers codes (Code_Aster and HYTEC) was then necessary. This thesis proposed a method of coupling between the two codes whose techniques are widely described in the manuscript.