Thesis advisor: Udayan Mohanty / Among the existing strategies to direct solar energy harvesting and storage, solar fuel production by photoelectrocatalysis promises a comparatively simple, low-cost route. The science behind this process is straightforward: stable semiconductors absorb sunlight and use the energy to excite charges, which then drive redox reactions at the surface. Careful studies of the photoelectrode surface provide important considerations in building a high-performance photoelectrode. Specifically, I focused on controlling the surface band alignment of Cu2O photocathode|water for hydrogen evolution reaction. A ZnS buried heterojunction is formed to improve the photovoltage. Then I focused on understanding the influence of chemical species on surface kinetics and energetics for water oxidation reaction. Two hematite photoanodes with preferably exposed {001} and {012} facets were examined. Further, I systematically studied three different types of surfaces, bare hematite, hematite with a heterogenized Ir water oxidation catalyst (WOC), and a heterogeneous IrOx WOC. While both WOCs improve the performance of hematite by a large margin, their working mechanisms are found to be fundamentally different. I also focused on utilizing surface photoexcited species to control product selectivity. Selective CO production by photoelectrochemical methane oxidation is successfully demonstrated. Detailed experimental investigations revealed that a synergistic effect by adjacent Ti3+ sites is the key to CO formation. / Thesis (PhD) — Boston College, 2018. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Baseado na técnica de Microextração Liquido-Líquido Dispersiva (DLLME) desenvolveu-se uma metodologia de extração para analisar, por Cromatografia Líquida de Alta Eficiência com detector ultravioleta (HPLC-UV), a presença do propilparabeno (PrP) e do butilparabeno (BuP) nas águas da Bacia do Rio Pardo. O método proposto apresentou um limite de detecção e de quantificação de 62,60 e 187,60 µg/L para o Prp e de 58,40 e 175,20 µg/L para o BuP. Análise das amostras coletadas (18 amostras) apresentou um teor de 2,2 a 6,8 µg/L para o PrP e de 1,9 a 4,9 µg/L para o Bup. Além de analisar a presença dos parabenos nas águas do Rio Pardo, estudou-se também a degradação do PrP, do BuP e da mistura PrP mais BuP ( PrP + BuP) pelas técnicas de fotólise e fotoeletrocatálise em solução de água deionizada e em água de rio (Rio Pardo) em diferentes concentrações (5, 10, 20 e 30 mg/L) e pH (4, 7 e 10). A remoção dos parabenos em ambas as técnicas foi superior a 99%. Na fotólise, o tempo de degradação da menor para a maior concentração variou de 25 a 85 minutos enquanto na fotoeletrocatálise ele foi de 12 a 55 minutos, sendo as melhores condições em água deionizada e em meio ácido e neutro (pH 4 e 7). Análise do Carbono Orgânico Total (TOC) das soluções fotolisadas em água deionizada e em diferentes pH\'s (4, 7 e 10) revelou, para o PrP, uma remoção de 16,3 a 25,25 %. Para o BuP, na mesma sequência de pH, a remoção foi de 15 a 23,55%. Na fotoeletrocatálise a remoção de TOC para o PrP nos pH 4, 7 e 10 variou de 33,3 a 36,5 % enquanto para o BuP ela foi de 35,2 a 38,3 %. Teste de citotoxicidade mostrou que o PrP, o BuP e a mistura PrP-BuP são atóxico para as células de fibroblastos Balb/c 3T3 clone A31 antes e após as degradações, todavia são estrogênicos para as células de adenocarcinoma mamário MCF-7. Para o PrP, após ambos os processos de degradação, a estrogenicidde foi completamente abolida, enquanto que para o BuP e para mistura (PrP+BuP) ela foi reduzida, porém não totalmente eliminada. / Based on the dispersive Liquid-Liquid Microextraction technique (DLLME) developed an extraction methodology to analyze by High Performance Liquid Chromatography with Ultraviolet detection (HPLC-UV), the presence of propylparaben (PrP) and butylparaben (BuP) in the waters of the Pardo River Basin. The proposed method has a limit of detection and quantification of 62,60 and 187,60 µg /L of PrP and 58.40 and 175.20 µg /L for BuP. Analysis of the samples (18 samples) showed a content of 2.2 to 6.8 µg / L for the PrP and 1.9 to 4.9 µg / L for the Bup. In addition to analyzing the presence of parabens in the waters of the Pardo River, studied also the degradation of PrP, BuP and mixture PrP more BuP (PrP + BuP) for photolysis and photoelectrocatalysis techniques in deionized water solution and river water (Pardo River) at different concentrations (5, 10, 20 and 30 mg / L) and pH (4, 7 and 10). Removal of parabens in both techniques was greater than 98%. The degradation time in the photolysis ranged from 25 to 85 minutes while in photoelectrocatalysis was of 12 to 55 minutes, being the best conditions in deionized water and in acidic and neutral medium (pH 4 and 7). Analysis of Total Organic Carbon (TOC) of the solution photolysed in deionized water at different pHs (4, 7 and 10) showed to PrP, a removal of 16.3 25.25%. For BuP in the same sequence pH, the removal was 15 to 23.55%. In photoelectrocatalysis TOC removal for PrP in pH 4, 7 and 10 ranged from 33.3 to 36.5% whereas for BuP it was 35.2 to 38.3%.Cytotoxicity test showed that PrP, BUP and PrP-BuP mixture is nontoxic to the cells fibroblasts Balb / c 3T3 clone A31 before and after degradation, however are estrogenic for breast adenocarcinoma cells MCF-7. For the PrP, after photolysis and photoelectrocatalysis, it was completely abolished whereas for BuP and mixture (PrP + BuP), it was reduced but not completely eliminated.

Baseado na técnica de Microextração Liquido-Líquido Dispersiva (DLLME) desenvolveu-se uma metodologia de extração para analisar, por Cromatografia Líquida de Alta Eficiência com detector ultravioleta (HPLC-UV), a presença do propilparabeno (PrP) e do butilparabeno (BuP) nas águas da Bacia do Rio Pardo. O método proposto apresentou um limite de detecção e de quantificação de 62,60 e 187,60 µg/L para o Prp e de 58,40 e 175,20 µg/L para o BuP. Análise das amostras coletadas (18 amostras) apresentou um teor de 2,2 a 6,8 µg/L para o PrP e de 1,9 a 4,9 µg/L para o Bup. Além de analisar a presença dos parabenos nas águas do Rio Pardo, estudou-se também a degradação do PrP, do BuP e da mistura PrP mais BuP ( PrP + BuP) pelas técnicas de fotólise e fotoeletrocatálise em solução de água deionizada e em água de rio (Rio Pardo) em diferentes concentrações (5, 10, 20 e 30 mg/L) e pH (4, 7 e 10). A remoção dos parabenos em ambas as técnicas foi superior a 99%. Na fotólise, o tempo de degradação da menor para a maior concentração variou de 25 a 85 minutos enquanto na fotoeletrocatálise ele foi de 12 a 55 minutos, sendo as melhores condições em água deionizada e em meio ácido e neutro (pH 4 e 7). Análise do Carbono Orgânico Total (TOC) das soluções fotolisadas em água deionizada e em diferentes pH\'s (4, 7 e 10) revelou, para o PrP, uma remoção de 16,3 a 25,25 %. Para o BuP, na mesma sequência de pH, a remoção foi de 15 a 23,55%. Na fotoeletrocatálise a remoção de TOC para o PrP nos pH 4, 7 e 10 variou de 33,3 a 36,5 % enquanto para o BuP ela foi de 35,2 a 38,3 %. Teste de citotoxicidade mostrou que o PrP, o BuP e a mistura PrP-BuP são atóxico para as células de fibroblastos Balb/c 3T3 clone A31 antes e após as degradações, todavia são estrogênicos para as células de adenocarcinoma mamário MCF-7. Para o PrP, após ambos os processos de degradação, a estrogenicidde foi completamente abolida, enquanto que para o BuP e para mistura (PrP+BuP) ela foi reduzida, porém não totalmente eliminada. / Based on the dispersive Liquid-Liquid Microextraction technique (DLLME) developed an extraction methodology to analyze by High Performance Liquid Chromatography with Ultraviolet detection (HPLC-UV), the presence of propylparaben (PrP) and butylparaben (BuP) in the waters of the Pardo River Basin. The proposed method has a limit of detection and quantification of 62,60 and 187,60 µg /L of PrP and 58.40 and 175.20 µg /L for BuP. Analysis of the samples (18 samples) showed a content of 2.2 to 6.8 µg / L for the PrP and 1.9 to 4.9 µg / L for the Bup. In addition to analyzing the presence of parabens in the waters of the Pardo River, studied also the degradation of PrP, BuP and mixture PrP more BuP (PrP + BuP) for photolysis and photoelectrocatalysis techniques in deionized water solution and river water (Pardo River) at different concentrations (5, 10, 20 and 30 mg / L) and pH (4, 7 and 10). Removal of parabens in both techniques was greater than 98%. The degradation time in the photolysis ranged from 25 to 85 minutes while in photoelectrocatalysis was of 12 to 55 minutes, being the best conditions in deionized water and in acidic and neutral medium (pH 4 and 7). Analysis of Total Organic Carbon (TOC) of the solution photolysed in deionized water at different pHs (4, 7 and 10) showed to PrP, a removal of 16.3 25.25%. For BuP in the same sequence pH, the removal was 15 to 23.55%. In photoelectrocatalysis TOC removal for PrP in pH 4, 7 and 10 ranged from 33.3 to 36.5% whereas for BuP it was 35.2 to 38.3%.Cytotoxicity test showed that PrP, BUP and PrP-BuP mixture is nontoxic to the cells fibroblasts Balb / c 3T3 clone A31 before and after degradation, however are estrogenic for breast adenocarcinoma cells MCF-7. For the PrP, after photolysis and photoelectrocatalysis, it was completely abolished whereas for BuP and mixture (PrP + BuP), it was reduced but not completely eliminated.

In this thesis, titanium dioxide (TiO2)-based thin film photocatalysts of different morphologies were synthesized and studied for their photoelectrocatalytic and photocatalytic properties. The superhydrophilicity of selected TiO2 films were also assessed. The work started with the synthesis of nanocrystalline TiO2 thin films with minimal porosity. A photoelectrocatalytic study was performed to evaluate the films?? photocurrent response in the presence of various organic compounds. At low concentrations, the amount of photocurrent generated was found to be influenced by the molecular structure of the organic compounds. As the concentration increased, the photocurrent response became dependent on the level of interaction of the organic compounds and their partially degraded intermediates with the TiO2 surface. Highly dispersed platinum (Pt) were added onto TiO2 films by a photo-deposition method, and their photocatalytic and photoelectrocatalytic activities were assessed using a novel thin-layer photo(electrochemical)-catalytic system. The system allowed the photocurrent data that originated from the photoelectrocatalysis process to be collected in the reaction cell, and the amount of organic compound being oxidized to be quantified. The Pt deposits were found to enhance photocatalysis by increasing the photogenerated charge-carriers separation, but conversely they retarded the photoelectrocatalysis process. The next part of the work covered the development of mesoporous TiO2 films via the evaporative-induced self-assembly procedure. The structural characteristics of the films were altered by controlling the relative humidity and temperature during the coating and thermal treatment processes. The effect of key structural parameters, such as film porosity, surface area and crystallinity, on the photoelectrocatalytic activity was investigated. These parameters were found to affect the photoelectrocatalysis because the performance of a catalyst in the photoelectrocatalysis application relies strongly on attributes such as the photocatalyst particles?? interconnectivity and the contact to the conducting substrate. The last part of this thesis demonstrated the effort undertaken to improve the UV-induced superhydrophilic effect of a TiO2 film. A multilayer structure of TiO2 nanoparticles was assembled to create a novel TiO2 film that required no UV-activation to induce a uniform water sheeting across its surface. The novel TiO2 thin film exhibited stable superhydrophilic wetting and anti-fogging behaviors after repetitive cycles of heat and wetting treatment, and this performance was affected by the porosity and surface hydroxyl (-OH) contents.

In this thesis, titanium dioxide (TiO2)-based thin film photocatalysts of different morphologies were synthesized and studied for their photoelectrocatalytic and photocatalytic properties. The superhydrophilicity of selected TiO2 films were also assessed. The work started with the synthesis of nanocrystalline TiO2 thin films with minimal porosity. A photoelectrocatalytic study was performed to evaluate the films?? photocurrent response in the presence of various organic compounds. At low concentrations, the amount of photocurrent generated was found to be influenced by the molecular structure of the organic compounds. As the concentration increased, the photocurrent response became dependent on the level of interaction of the organic compounds and their partially degraded intermediates with the TiO2 surface. Highly dispersed platinum (Pt) were added onto TiO2 films by a photo-deposition method, and their photocatalytic and photoelectrocatalytic activities were assessed using a novel thin-layer photo(electrochemical)-catalytic system. The system allowed the photocurrent data that originated from the photoelectrocatalysis process to be collected in the reaction cell, and the amount of organic compound being oxidized to be quantified. The Pt deposits were found to enhance photocatalysis by increasing the photogenerated charge-carriers separation, but conversely they retarded the photoelectrocatalysis process. The next part of the work covered the development of mesoporous TiO2 films via the evaporative-induced self-assembly procedure. The structural characteristics of the films were altered by controlling the relative humidity and temperature during the coating and thermal treatment processes. The effect of key structural parameters, such as film porosity, surface area and crystallinity, on the photoelectrocatalytic activity was investigated. These parameters were found to affect the photoelectrocatalysis because the performance of a catalyst in the photoelectrocatalysis application relies strongly on attributes such as the photocatalyst particles?? interconnectivity and the contact to the conducting substrate. The last part of this thesis demonstrated the effort undertaken to improve the UV-induced superhydrophilic effect of a TiO2 film. A multilayer structure of TiO2 nanoparticles was assembled to create a novel TiO2 film that required no UV-activation to induce a uniform water sheeting across its surface. The novel TiO2 thin film exhibited stable superhydrophilic wetting and anti-fogging behaviors after repetitive cycles of heat and wetting treatment, and this performance was affected by the porosity and surface hydroxyl (-OH) contents.

In this work, electrophotocatalytic disinfection on selected microorganisms was verified. The electrophotocatalytic system allows the application of electrical bias to the photoanode coated with a titanium dioxide layer. The disinfecting effect was observed on E.coli and C.glabrata in aqueous solution. The effect of radiation intensity on electrophotocatalysis and selected optimal conditions for further experiments was observed in the E. coli organism. Photocatalytic disinfection was carried out under suitable conditions on C.glabrata yeast and the effect of sodium sulfate electrolyte on electrophotocatalytic disinfection was observed in this case.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24180号 / 理博第4871号 / 新制||理||1697(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 寺西 利治, 教授 島川 祐一, 教授 倉田 博基 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Este trabalho visa o estudo de processos de degradação fotocatalítica e fotoeletrocatalítica de corantes sobre dióxido de titânio. O enfoque está voltado ao uso de técnicas espectroscópicas, com especial destaque para o desenvolvimento de metodologias de espectroscopia vibracional Raman intensificada. Nesse sentido, tem-se em vista a investigação dos mecanismos envolvidos nos processos de fotodegradação e fotoeletrodegradação de corantes, através da identificação de intermediários e produtos de processos de degradação por técnicas de espectroscopia eletrônica e Raman. Os estudos de fotocatálise são também expandidos para ambientes eletroquímicos. Nos chamados processos fotoeletrocatalíticos, a combinação de processos eletroquímicos e fotoquímicos mostra-se bastante promissora para a degradação de poluentes orgânicos. O primeiro desafio no desenvolvimento desse trabalho foi construir o fotorreator adequado que permitisse a obtenção de amostras para serem analisadas por espectroscopia Raman, e apresentasse boa eficiência nos processos de fotocatálise e também fotoeletrocatálise. Encontrado o fotorreator adequado, investigamos o comportamento cinético dos processos foto(eletro)degradação de corantes, buscando verificar a dependência com o potencial eletroquímico aplicado, o efeito do eletrólito suporte, e a identificação de intermediários formados durante o processo de degradação. Analisamos também aspectos relacionados aos mecanismos de adsorção de corantes sobre a superfície do dióxido de titânio. Tais aspectos podem ser de significativa relevância no desenvolvimento de técnicas eficazes para o tratamento de poluentes orgânicos. Nossos estudos estiveram principalmente centrados em dois corantes: o azocorante verde de Janus e o corante antraquinônico alizarina vermelha S. Os resultados obtidos nos estudos da cinética dos processos fotoeletrocatalíticos sugerem que o efeito do potencial aplicado depende de maneira significativa da natureza química do corante. Observou-se uma tendência dos processos fotoeletrocatalíticos serem mais eficientes na remoção da coloração da solução corante do verde de Janus quando comparados aos fotocatalíticos. Tal tendência não foi observada para o corante alizarina vermelha S. Essa diferença de comportamento pôde ser relacionada à natureza das interações específicas de entre cada corante e a superfície do catalisador. Nossos estudos a respeito dos mecanismos envolvidos nos processos de degradação do verde de Janus revelaram que as primeiras etapas dos processos de fotodegradação e fotoeletrodegradação seguem mecanismos diferentes. Os resultados obtidos mostram que a degradação do verde de Janus em suspensão de TiO2 envolve entre suas etapas modificações na ligação azo desse corante (N=N), resultando na formação de um composto intermediário derivado da fenossafranina. No processo fotoeletrocatalítico, por outro lado, observa-se um mecanismo diferenciado o qual não envolve em suas etapas iniciais a quebra da ligação azo do corante / This work focuses on the study of photocatalytic and photoelectrocatalytic degradation processes of dyes over titanium dioxide. The main approach is based on the use of spectroscopic techniques, with special emphasis to methodologies based on surface-enhanced Raman spectroscopy. Within this context, the mechanisms involved in the photodegradation and photoelectrodegradation of dyes are investigated by the identification of degradation intermediates through vibrational and electronic spectroscopies. In the so-called photoelectrocatalytic processes, the combination of electrochemical and photochemical processes is an interesting and promising approach for the degradation of a wide variety of organic pollutants. The first step in the development of the present work was to build a photo reactor that allowed the analysis of samples through Raman spectroscopy and presented a good efficiency for both photocatalytic and photoelectrocatalytic processes. We then investigated the kinetic behavior of the photo(electro)degradation of dyes in order to verify the dependence upon the electrochemical applied potential, the effect of the supporting electrolyte, and the identification of intermediate products formed during the degradation process. We also analyzed aspects related to the adsorption mechanisms of the dyes on the titanium dioxide surface. Such aspects can be relevant to the understanding and to the development of efficient techniques for the remediation of organic pollutants. Our studies focused mainly on two dyes: the azo dye Janus green and the anthraquinonic dye alizarin red S. The results obtained in the kinetic study of the photoelectrocatalytic processes suggest that the effect of the applied electrochemical potential strongly depends on the chemical nature of the investigated dye. We have observed that the decolorization of Janus green is favored for photoelectrocatalytic process as compared to the photocatalytic degradation. Such behavior was not observed for the anthraquinonic dye alizarin red S. This difference was related to the nature of the specific interactions between each dye and the catalyst surface. Our studies regarding the mechanisms of degradation revealed that the first steps of the photocatalytic and photoelectrocatalytic processes of Janus green followed different routes. The obtained results indicate that the degradation of Janus green in aqueous TiO2 suspension involves changes in the azo bond (N=N), resulting in the formation of an intermediate compound a derived from the phenosafranine structure, whereas for the photoelectrocatalytic process there are evidences of a different mechanism that does not involve the cleavage of the azo bond.

Neste projeto investigou-se o uso de três técnicas: (i) eletrólise, (ii) fotoeletrocatálise e (iii) fotólise, na degradação do hormônio estradiol, comumente encontrado nos esgotos domésticos, e que geram sérias preocupações com a ação nefasta que podem provocar na vida selvagem e humana. Os ensaios eletroquímicos foram realizados sobre eletrodos de platina e carbono vítreo. A técnica de fotoeletrocatálise foi aplicada empregando-se placas de titânio recobertas com nanocamadas de TiO2. Como fonte de radiação ultravioleta utilizou-se uma lâmpada de vapor de mercúrio de 125 W tanto na fotoeletrocatálise como na fotólise. Através dos estudos da oxidação do estradiol por voltametria cíclica, sobre os eletrodos acima mencionados, foi possível definir o seu potencial de oxidação em soluções de KCl e tampão fosfato (pH 7), sobre platina e carbono vítreo. Estes parâmetros serviram de base para a realização das eletrólises sob condições controladas. A fotoeletrocatálise do estradiol foi realizada sobre Ti/TiO2 preparado por técnica sol-gel e se mostrou muito mais efetiva que a eletrólise eletrolítica. Finalmente, a fotólise também foi testada empregando-se apenas a lâmpada de vapor de mercúrio. Neste último caso a degradação do estradiol foi ligeiramente inferior que aquela observada por fotoeletrocatálise. Identificou-se que em soluções de KCl há a formação de hipoclorito, o que auxilia o processo oxidativo do estradiol. Espectroscopia de UV-vís e cromatografia líquida (HPLC) foram empregadas para acompanhar os processos de degradação. Apesar de ter sido observado o surgimento de bandas e picos cromatográficos devidos aos produtos formados, não foi possível identifica-los. / In this project the use of three techniques was investigated: (i) electrolysis, (ii) photoelectrocatalysis and (iii) photolysis, in the degradation of the hormone estradiol, commonly found in the domestic sewers. This hormone can generate serious concerns with a disastrous action that can provoke in the wild and human life. The electrochemistry studies were accomplished on platinum and glassy carbon electrodes. The photoelectrocatalysis technique was applied using titanium plate covered with nanolayers of TiO2. As a source of ultra-violet radiation was used a lamp bulb of mercury vapor of 125 W for the photoelectrocatalysis as also in the photolysis. Through the studies of the oxidation of the estradiol by cyclic voltammetry, on the electrodes above mentioned, it was possible to define the oxidation potential of the organic specie in both solutions, KCl and phosphate buffers (pH 7), for platinum and glassy carbon. These parameters served as base for the realization of the electrolysis under controlled conditions. The photoelectrocatalysis of the estradiol was accomplished on Ti/TiO2 prepared by sol-gel technique and it was shown much more effective than the electrolyitc electrolysis. Finally, the photolysis was also tested being just used the mercury vapor lamp. In this last case the degradation of the estradiol was lightly inferior to that observed by photoelectrocatalysis It was identified that in solutions of KCl there is the hypochlorite formation, what aids the oxidation of the estradiol. Spectroscopy of UV-vis and high performance liquid chromatography (HPLC) were used to accompany the degradation processes. In spite of the appearance of bands and chromatographyc peaks owed to the formed products having been observed, however, it were not possible identify them.

Made available in DSpace on 2014-06-11T19:35:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-16Bitstream added on 2014-06-13T19:44:58Z : No. of bitstreams: 1 faber_m_dr_araiq.pdf: 616939 bytes, checksum: 5db3f5c1f7c0957c9c2391a95b6380b6 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os estudos de degradação do corante VAT idantreno verde oliva foram realizados empregando-se solução 5x10-5 mol L-1 do corante em meio de NaCl 0,1 mol L-1 , pH=2,0 por meio do processo fotoeletrocatalítico sobre eletrodos de filmes finos de Ti/TiO2. Após 210 min de tratamento foi obtido 100% de descoloração e 86 % de mineralização. A aplicação do método fotocatalítico nas mesmas condições experimentais leva a apenas 60% de remoção do corante, indicando que o método fotoeletrocatalítico apresenta maior eficiência que a técnica de fotocatálise. A degradação do corante ácido vermelho 8 foi investigada através de processo fotoquímico empregando irradiação UV com lâmpada germicida de 4 W e lâmpada de mercúrio de 80 W. Foi observado significativa remoção da cor, porém análises de carbono orgânico total mostraram que o processo não apresenta nenhuma mineralização da matéria orgânica. Utilizando-se lâmpada de 80 W a degradação do corante ocorre segundo reação de pseudo primeira ordem com constante de velocidade de 0,0122 min-1 . A degradação do corante vermelho 8 é mais eficiente pelo processo fotocatalítico. A oxidação fotocatalítica de solução 5x10-5 mol L-1 do corante em meio de Na2SO4 0,1 mol L-1 , pH=6,0, sobre vidro/TiO2 promoveu 100 % de remoção da cor e aproximadamente 43 % de mineralização do corante. A eficiência fotocatalítica de filmes de TiO2 suportados em substrato de vidro obtidos pelo método dip-coating foi investigada testando-se a degradação do corante ácido vermelho em filmes obtidos variando-se os parâmetros: número de etapas de recobrimento, velocidade de deposição e temperatura de calcinação. O filme que mostrou maior eficiência fotocatalítica na degradação do corante ácido vermelho 8, foi construído com 1 depósito de TiO2, velocidade de recobrimento de 50 mm/min e temperatura... / Studies of degradation of the dye VAT Indanthrene olive green were performed using solution was 5x10-5 mol L-1 dye in NaCl 0.1 mol L-1 , pH = 2.0 through the process photoelectrocatalytic thin-film electrodes Ti/TiO2. After 210min of treatment was obtained 100% discoloration and 86% of mineralization. The application of the photocatalytic the same experimental condition leads to 60% removal of dye, indicating that the method photoelectrocatalytic is more efficient than the technique of photocatalysis. The degradation of acid red dye 8 was investigated by photochemical process using irradiation with UV germicidal lamp 4W and mercury lamp of 80W. Have been observed significant removal of color, but the analysis of carbon organic total no shows mineralization of organic matter. Using 80W lamp degradation of the dye is second reaction under pseudo first order rate constant of 0.0122 min-1 . The degradation of the red dye 8 is more efficient for the photocatalytic process. The photocatalytic oxidation of solution 5x10-5 mol L-1 dye in the midst of Na2SO4 0.1 mol L-1 , pH= 6.0 on glass/TiO2 promoted 100% removal of color and approximately 43% mineralization of the dye. The efficiency of photocatalytic TiO2 films supported on glass substrate obtained by dip-coating method was investigated by testing the degradation of acid red dye in films obtained by varying the parameters: number of steps of coating, deposition rate and temperature calcination. The film showed better photocatalytic degradation of dye Acid Red 8, was built with 1 deposit TiO2, coating speed of 50 mm/min and calcination temperature of 350°C film. Under these conditions the degradation of the dye second reaction is pseudo first-order rate constant of degradation of k = 0.121 min-1 . Therefore, it is concluded that the technique of photolysis and photocatalysis can be an excellent alternative to decolorize... (Complete abstract click electronic access below)