Yes / Alterations of Endothelial cells (ECs) play a critical role in different pathogenesis of many serious human diseases, and dysfunction of the vascular endothelium is an indicator for human disorders. Endothelial dysfunction is considered to be an early indicator for atherosclerosis, which is characterised by overexpression of adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Hydrogen peroxide (H2O2) released via neutrophils is an important mediator of endothelial cell function. Ambient production of superoxide anion (O2−) and subsequently H2O2 at low levels is critical for regulating endothelial cell functions and proliferation. In this study, we investigated the effects of H2O2 on the expression of adhesion molecules VCAM-1 and ICAM-1 in cultured human umbilical vein endothelial cells (HUVECs). Intracellular superoxide anion production was detected by using p-Nitro Blue Tetrazolium (NBT) assay. Our results showed that administration of 100μM of H2O2 on HUVECs for 2, 6, 12 and 24 h induced a time-dependent increase in ICAM-1 and VCAM-1 mRNA and protein expression levels with a significant increase observed from 6 h. HUVECs exposed to H2O2 exhibit increased O2−, suggesting that H2O2 induced oxidative stress may be a reasonable for atherosclerosis. This increase can be reduced by the flavonoid, N-acetyl cysteine (NAC). The modulation of endothelial cell function through this mechanism may underlie the contribution of H2O2 to the development of vascular disease.

Tesis por compendio / [ES] El consumo actual de combustibles fósiles supone la emisión de millones de megatones de CO2 cada año, lo que ha tenido consecuencias potencialmente catastróficas como el efecto invernadero, la acidificación de los océanos y la eutrofización de las aguas, entre otras. Por lo tanto, la utilización de CO2 para la producción de combustibles y productos químicos de valor ha atraído mucho interés a lo largo de los años, especialmente empleando luz solar. A lo largo de los años, se han probado una gran variedad de materiales para tecnologías fotocatalíticas, principalmente TiO2, CdS, LDH, MOF y nitruros de carbono, entre otros. A pesar de esto, todos estos materiales adolecen de importantes inconvenientes, como una insuficiente captación de luz, estabilidad o baja producción. Y, por lo tanto, su aplicación en posibles tecnologías industriales fotocatalíticas es muy limitada a nivel industrial. Además de los procesos fotocatalíticos, que se componen principalmente de portadores de carga fotogenerados que facilitan las reacciones redox, los procesos fototérmicos representan una alternativa atractiva para las futuras tecnologías solares. La amplia utilización del espectro solar, el rápido calentamiento por irradiación de luz a través de "nanocalentadores" y "electrones calientes" que interactúan con sustratos son algunas de las características que conducen a los altos rendimientos catalíticos que generalmente se observan en las reacciones fototérmicas. En la presente tesis doctoral, se han empleado diferentes materiales, como clústeres de Fe incrustados en grafeno dopado con nitrógeno, hidroxiapatita dopada con Co y nanopartículas de Ru soportadas sobre titanato de estroncio, como catalizadores fototérmicos para la hidrogenación selectiva de CO2 a CO o metano, tanto en flujo discontinuo como continuo. Admás, se han investigado muchos factores que influyen en esta reacción, como la naturaleza de los grupos/nanopartículas metálicas incrustadas, las cantidades de dopantes y la influencia de la irradiación incidente, entre otros. Además de la catálisis fototérmica, la actual tesis doctoral también aborda procesos fotocatalíticos como la ruptura del agua o la reducción del O2 a H2O2, empleando nuevos compuestos de nitruro de carbono. Ya sea sensibilizando el fotocatalizador para la absorción de luz visible o mejorando las propiedades electrónicas mediante la formación de heterouniones, se lograron resultados fotocatalíticos notables. / [CA] El consum actual de combustibles fòssils suposa l'emissió de milions de megatons de CO2 cada any, cosa que ha tingut conseqüències potencialment catastròfiques com l'efecte hivernacle, l'acidificació dels oceans i l'eutrofització de les aigües, entre d'altres. Per tant, la utilització de CO2 per a la producció de combustibles i productes químics de valor ha atret molt interès al llarg dels anys, especialment emprant llum solar. Al llarg dels anys, s'han provat una gran varietat de materials per a tecnologies fotocatalítiques, principalment TiO2, CdS, LDH, MOF i nitrurs de carboni, entre d'altres. Tot i això, tots aquests materials pateixen importants inconvenients, com una insuficient captació de llum, estabilitat o baixa producció. I, per tant, la seva aplicació a possibles tecnologies industrials fotocatalítiques és molt limitada a nivell industrial. A més dels processos fotocatalítics, que es componen principalment de portadors de càrrega fotogenerats que faciliten les reaccions redox, els processos fototèrmics representen una alternativa atractiva per a les futures tecnologies solars. L'àmplia utilització de l'espectre solar, l'escalfament ràpid per irradiació de llum a través de "nanoescalfadors" i "electrons calents" que interactuen amb substrats són algunes de les característiques que condueixen als alts rendiments catalítics que generalment s'observen en les reaccions fototèrmiques. En aquesta tesi doctoral, s'han emprat diferents materials, com clústers de Fe incrustats en grafè dopat amb nitrogen, hidroxiapatita dopada amb Co i nanopartícules de Ru suportades sobre titanat d'estronci, com a catalitzadors fototèrmics per a la hidrogenació selectiva de CO2 a CO o metà, tant en flux discontinu com continu. A més, s'han investigat molts factors que influeixen en aquesta reacció, com ara la naturalesa dels grups/nanopartícules metàl·liques incrustades, les quantitats de dopants i la influència de la irradiació incident, entre d'altres. A més de la catàlisi fototèrmica, l'actual tesi doctoral també aborda processos fotocatalítics com ara la ruptura de l'aigua o la reducció de l'O2 a H2O2, emprant nous compostos de nitrur de carboni. Ja sigui sensibilitzant el fotocatalitzador per a l'absorció de llum visible o millorant les propietats electròniques mitjançant la formació d'heterounions, es van assolir resultats fotocatalítics notables. / [EN] Fossil fuel consumption accounts for millions of megatons of CO2 emitted every year, which has led to potentially catastrophic consequences such as the greenhouse effect, ocean acidification and water eutrophication, besides others. Thus, the utilization of CO2 for fuels and value chemicals has attracted much interest over the years, especially employing solar light. Over the years, a variety of promising materials have undergone trial for potential photocatalytic technologies, mainly TiO2, CdS, LDHs, MOFs and carbon nitrides among others, yet all these materials suffer from important drawbacks such as insufficient light harvesting, stability, or low production outputs, hence limiting their application in potential photocatalytic industrial technologies. Besides photocatalytic processes, mainly comprising of photogenerated charge carriers that facilitate redox reactions, photothermal processes represent an attractive alternative for future solar technologies. Broad utilization of the solar spectrum, strong heating upon light irradiation through "nano-heaters" and possibly "hot electrons" interacting with either semiconductors or substrate molecules are some characteristics that lead to the high catalytic outputs generally observed in photothermal reactions. In the current doctoral thesis, different materials such as Fe clusters imbedded on nitrogen doped graphene, Co doped hydroxyapatite and Ru nanoparticles supported on strontium titanate have been employed as photothermal catalysts for the photothermal hydrogenation of CO2 to either CO or methane, under both batch and flow conditions. Thus, many factors influencing this reaction have been investigated, such as the nature of embedded metallic clusters/nanoparticles, dopant amounts and the power of incident irradiation among others. Besides photothermal catalysis, the current doctoral thesis also addresses photocatalytic processes such as water splitting or O2 reduction to H2O2, employing novel carbon nitride composites. By either sensitizing the photocatalyst for visible light absorption or enhancing the electronic properties through heterojunction formation, remarkable photocatalytic outputs were achieved. / Szalad, H. (2024). Production of Solar Fuels Employing Different Materials Via Photocatalytic or Photothermal Pathways [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/206848 / Compendio

A presença de antibióticos no ecossistema representa um sério risco à saúde humana e animal em virtude do desenvolvimento crescente de resistência bacteriana. Uma vez que a maioria dos antibióticos é persistente à degradação biológica, os processos oxidativos avançados são apontados como uma das tecnologias mais efetivas para decompor esses compostos em águas residuárias. A bacitracina zíncica (Bc-Zn) é um potente antibiótico constituído por uma mistura complexa de peptídeos não-biodegradáveis, conjugados ao zinco. Apesar de ser um antibiótico amplamente consumido na medicina humana e animal, é preocupante a escassez de estudos que investigam sua degradação e destino ambiental. O presente trabalho analisou a degradação da Bc-Zn através dos processos de fotólise direta e UV/H2O2 em diferentes condições de radiação UVC e concentração inicial de H2O2. Os parâmetros cinéticos rendimento quântico da fotólise, constantes cinéticas de pseudo-primeira ordem e constante cinéticas de segunda ordem foram satisfatoriamente estimados pela modelagem do sistema fotoquímico experimental. Os resultados revelaram que a fotólise direta permitiu degradar todos os congêneres da mistura de Bc-Zn nas maiores doses de radiação UVC empregadas. No entanto, não houve remoção de TOC após 120 minutos de irradiação. A adição de H2O2 acelerou substancialmente a fotodegradação do antibiótico, apresentando constantes cinéticas de pseudo-primeira ordem uma ordem de grandeza superiores às obtidas por fotólise direta. Além disso, remoção considerável de até 71% do TOC foi alcançada. A análise estatística demonstrou que a radiação UV foi um fator bem mais significativo para a fotodegradação da Bc-Zn em relação à concentração inicial de H2O2, sendo as melhores condições do processo alcançadas para a maior taxa específica de emissão de fótons (1,11×10-5 Einstein L-1 s-1). Ensaios biológicos com soluções tratadas por fotólise direta e UV/H2O2 indicaram remoção completa da atividade antimicrobiana residual, ainda que os produtos da fotodegradação tenham se mostrado não-biodegradáveis. Análises de toxicidade indicaram que o metal zinco presente no antibiótico é responsável pela a toxicidade no micro-organismo-teste Vibrio fischeri. Estudos adicionais devem ser realizados para identificar os sub-produtos formados, bem como para investigar a degradação da Bc-Zn em efluentes industriais reais. / The presence of antibiotics in ecosystems represents a serious risk to human and animal health, caused by the increase in bacterial resistance. Since most antibiotics resist to biological degradation, advanced oxidation processes are pointed out as the most effective technologies for degrading these compounds in wastewater. Zinc bacitracin (Bc-Zn) is a potent antibiotic with a complex mixture of non-biodegradable peptides conjugated to zinc. Despite being a widely used antibiotic in human and animal medicine, the scarcity of studies dealing with its degradation and environmental fate is a matter of concern. In this work, Bc-Zn degradation by direct photolysis and the UV/H2O2 process was investigated for different UVC radiation conditions and initial H2O2 concentrations. Kinetic parameters, namely the photolysis quantum yield, pseudo-first order kinetic constants and second-order kinetic constants, were satisfactorily estimated from experimental data by modeling the photochemical system. The results showed that all the congeners of the Bc-Zn mixture were photolyzed at the highest UVC doses applied, while no TOC removal was observed after 120 minutes of irradiation. The addition of H2O2 substantially accelerated Bc-Zn photodegradation, with pseudo-first order kinetic constants of one order of magnitude higher than those observed under direct photolysis. In addition, a remarkable removal of up to 71% of TOC was achieved. Statistical analyses showed that UV radiation had a much more important effect on Bc-Zn photodegradation in comparison with initial H2O2 concentration, with the best process conditions achieved for the highest specific photon emission rate (1.11×10-5 Einstein L-1 s-1). Biological assays carried out with the solutions treated by direct photolysis and UV/H2O2 revealed no residual antimicrobial activity, though photodegradation products remained non-biodegradable. In addition, toxicity analyses indicated that the zinc metal present in the antibiotic is responsible for the toxic effect on the test microorganism Vibrio fischeri. Finally, further studies should be performed to identify the by-products formed and to investigate Bc-Zn degradation in real industrial wastewater.

A presença de antibióticos no ecossistema representa um sério risco à saúde humana e animal em virtude do desenvolvimento crescente de resistência bacteriana. Uma vez que a maioria dos antibióticos é persistente à degradação biológica, os processos oxidativos avançados são apontados como uma das tecnologias mais efetivas para decompor esses compostos em águas residuárias. A bacitracina zíncica (Bc-Zn) é um potente antibiótico constituído por uma mistura complexa de peptídeos não-biodegradáveis, conjugados ao zinco. Apesar de ser um antibiótico amplamente consumido na medicina humana e animal, é preocupante a escassez de estudos que investigam sua degradação e destino ambiental. O presente trabalho analisou a degradação da Bc-Zn através dos processos de fotólise direta e UV/H2O2 em diferentes condições de radiação UVC e concentração inicial de H2O2. Os parâmetros cinéticos rendimento quântico da fotólise, constantes cinéticas de pseudo-primeira ordem e constante cinéticas de segunda ordem foram satisfatoriamente estimados pela modelagem do sistema fotoquímico experimental. Os resultados revelaram que a fotólise direta permitiu degradar todos os congêneres da mistura de Bc-Zn nas maiores doses de radiação UVC empregadas. No entanto, não houve remoção de TOC após 120 minutos de irradiação. A adição de H2O2 acelerou substancialmente a fotodegradação do antibiótico, apresentando constantes cinéticas de pseudo-primeira ordem uma ordem de grandeza superiores às obtidas por fotólise direta. Além disso, remoção considerável de até 71% do TOC foi alcançada. A análise estatística demonstrou que a radiação UV foi um fator bem mais significativo para a fotodegradação da Bc-Zn em relação à concentração inicial de H2O2, sendo as melhores condições do processo alcançadas para a maior taxa específica de emissão de fótons (1,11×10-5 Einstein L-1 s-1). Ensaios biológicos com soluções tratadas por fotólise direta e UV/H2O2 indicaram remoção completa da atividade antimicrobiana residual, ainda que os produtos da fotodegradação tenham se mostrado não-biodegradáveis. Análises de toxicidade indicaram que o metal zinco presente no antibiótico é responsável pela a toxicidade no micro-organismo-teste Vibrio fischeri. Estudos adicionais devem ser realizados para identificar os sub-produtos formados, bem como para investigar a degradação da Bc-Zn em efluentes industriais reais. / The presence of antibiotics in ecosystems represents a serious risk to human and animal health, caused by the increase in bacterial resistance. Since most antibiotics resist to biological degradation, advanced oxidation processes are pointed out as the most effective technologies for degrading these compounds in wastewater. Zinc bacitracin (Bc-Zn) is a potent antibiotic with a complex mixture of non-biodegradable peptides conjugated to zinc. Despite being a widely used antibiotic in human and animal medicine, the scarcity of studies dealing with its degradation and environmental fate is a matter of concern. In this work, Bc-Zn degradation by direct photolysis and the UV/H2O2 process was investigated for different UVC radiation conditions and initial H2O2 concentrations. Kinetic parameters, namely the photolysis quantum yield, pseudo-first order kinetic constants and second-order kinetic constants, were satisfactorily estimated from experimental data by modeling the photochemical system. The results showed that all the congeners of the Bc-Zn mixture were photolyzed at the highest UVC doses applied, while no TOC removal was observed after 120 minutes of irradiation. The addition of H2O2 substantially accelerated Bc-Zn photodegradation, with pseudo-first order kinetic constants of one order of magnitude higher than those observed under direct photolysis. In addition, a remarkable removal of up to 71% of TOC was achieved. Statistical analyses showed that UV radiation had a much more important effect on Bc-Zn photodegradation in comparison with initial H2O2 concentration, with the best process conditions achieved for the highest specific photon emission rate (1.11×10-5 Einstein L-1 s-1). Biological assays carried out with the solutions treated by direct photolysis and UV/H2O2 revealed no residual antimicrobial activity, though photodegradation products remained non-biodegradable. In addition, toxicity analyses indicated that the zinc metal present in the antibiotic is responsible for the toxic effect on the test microorganism Vibrio fischeri. Finally, further studies should be performed to identify the by-products formed and to investigate Bc-Zn degradation in real industrial wastewater.

A indústria têxtil gera grandes volumes de efluentes com elevada carga orgânica, forte coloração e toxicidade. Neste trabalho, estuda-se o tratamento de solução aquosa contendo o corante Solophenyl Yellow Arle 154% por meio dos processos O3-H2O2/UV e foto-Fenton, avaliando-se as repostas: remoção de cor em 5 minutos, remoção de cor em 60 minutos, taxa máxima de remoção de cor e remoção de COT em 60 minutos. Os experimentos foram realizados em semibatelada com circulação usando um reator fotoquímico com campo de radiação anular coaxial, constituído de corpo cilíndrico em aço com refletor interno de alumínio para 12 lâmpadas fixadas simetricamente na superfície refletora e um tubo reator em quartzo de 0,7 L, posicionados verticalmente no eixo do refletor. Para o processo O3-H2O2/UV foram utilizadas lâmpadas Phillips TUV (36 W, 254 nm). A corrente gasosa contendo O3 foi introduzida no reator por meio de um difusor. Para o processo foto-Fenton foram utilizadas lâmpadas Sylvania (12 W cada, 300 400 nm) e concentração de Fe(II) de 0,25 mmol/L. Em ambos os processos, solução de peróxido de hidrogênio foi adicionada durante os 30 minutos iniciais de tratamento. As amostras foram analisadas por medidas de carbono orgânico total (COT) e remoção de cor (absorbância medida em 405 nm em espectrofotômetro UV-visível). Em ambos os processos utilizou-se o planejamento experimental Doehlert, definindo os valores mínimo e máximo para cada variável adotada. No caso do processo O3- H2O2/UV (ETAPA I), foram estudados os efeitos da potência elétrica total das lâmpadas (144 432 W), concentração de H2O2 (5 30 mmol/L), concentração inicial de corante (20 100 mg/L), concentração de ozônio (10 40 mg/L) e pH (3 10). No processo foto-Fenton (ETAPA II), estudaram-se os efeitos da potência (160 480 W), concentração de H2O2 (5 30 mmol/L) e concentração inicial de corante (20 100 mg/L). Os resultados da ETAPA I indicaram que o aumento da concentração do corante, em meio ácido, aumenta a remoção de cor em 5 e 60 minutos, sugerindo a eficiência da ação via ozônio molecular sob o grupo cromóforo do corante. Os melhores resultados apresentaram remoção acima de 95% em 5 e 60 minutos de tratamento. Entretanto, para a remoção de COT em 60 minutos o processo não foi eficiente, apresentando resultado máximo de 35,6%. Na ETAPA II obtiveram-se resultados menos satisfatórios para remoção de cor se comparados aos da ETAPA I (56,1% em 5 minutos e 78% em 60 minutos de tratamento), mas melhores em relação à remoção de COT em 60 minutos atigindo 45,1% de remoção. As maiores taxas de remoção de cor foram observadas nos 5 primeiros minutos de tratamento para todos os experimentos. Experimentos complementares realizados em uma terceira etapa (ETAPA III) mostraram que a aplicação do processo O3 seguido do processo foto-Fenton permitiu resultados satisfatórios tanto para remoção de cor (97,2%), quanto para remoção de COT (69,5%). O estudo da ação do processo O3 em modo contínuo e a avaliação econômica preliminar do processo integrado O3 - foto-Fenton sugerem o potencial de aplicação do tratamento integrado a indústrias têxteis. / The textile industry generates large volumes of wastewater with high organic load, strong coloration and toxicity. In this work, the treatment of an aqueous solution containing the dye Solophenyl Yellow Arle 154% was studied by the O3-H2O2/UV and photo-Fenton processes, in order to evaluate the responses color removal after 5 minutes; color removal after 60 minutes; maximum rate of color removal; and TOC removal after 60 minutes. The experiments were carried out in the semi-batch mode with circulation using a photochemical reactor with annular coaxial radiation field, consisting of a cylindrical stainless steel support with an aluminum internal reflector with 12 lamps fixed symmetrically in the internal reflecting surface, and a quartz tube reactor of 0.7 L, positioned vertically along the axis of the reflector. For the O3- H2O2/UV process, Phillips TUV lamps (36 W, 254 nm) were used; the gas stream containing zone was introduced into the reactor through a diffuser. For the photo- Fenton process, Sylvania lamps (12 W each, 300 - 400 nm) and a concentration of Fe (II) of 0.25 mmol/L were used. In both cases, the hydrogen peroxide solution was added in the first 30 minutes of treatment. The samples were analyzed by the measurement of total organic carbon (TOC) and color removal (absorbance measured at 405 nm in a UV-visible spectrophotometer). In both cases the Doehlert experimental design was used, defining the minimum and maximum values of each variable adopted. In the case of O3-H2O2/UV process (PHASE I), the effects of the total electric power of the lamps (144 - 432 W), H2O2 concentration (5 - 30 mmol/L), initial dye concentration (20 - 100 mg/L), ozone concentration (10 - 40 mg/L), and pH (3 - 10) were studied. For the photo-Fenton process, the studied variables were: total electric power of the lamps (160 - 480 W), H2O2 concentration (5 - 30 mmol/L), and initial dye concentration (20 - 100 mg/L). The results of PHASE I indicated that the increase of dye concentration in acidic conditions increases color removal after 5 and 60 minutes, thus suggesting the efficiency of molecular ozone action upon the chromophore group of the dye. The best results showed color removal above 95% after 5 and 60 minutes of treatment. However, for the TOC removal the process was not efficient, with maximum removal after 60 minutes of only 35.6%. In PHASE II less satisfactory results for color removal were obtained in comparison with PHASE I (56.1% after 5 minutes and 78% after 60 minutes of treatment), but with higher TOC removal after 60 minutes, achieving over 45.1%. The highest color removal rates were observed within the first 5 minutes of treatment for all runs. Additional experiments carried out in PHASE III showed that the oxidation by O3 followed by the photo-Fenton process enabled to achieve suitable results for both color (97.2%) and TOC removals (69.5%). The study of the O3 process in the continuous mode and a preliminary economic evaluation suggests a high potential for the use of the integrated O3-photo-Fenton process in textile industries.

A indústria têxtil gera grandes volumes de efluentes com elevada carga orgânica, forte coloração e toxicidade. Neste trabalho, estuda-se o tratamento de solução aquosa contendo o corante Solophenyl Yellow Arle 154% por meio dos processos O3-H2O2/UV e foto-Fenton, avaliando-se as repostas: remoção de cor em 5 minutos, remoção de cor em 60 minutos, taxa máxima de remoção de cor e remoção de COT em 60 minutos. Os experimentos foram realizados em semibatelada com circulação usando um reator fotoquímico com campo de radiação anular coaxial, constituído de corpo cilíndrico em aço com refletor interno de alumínio para 12 lâmpadas fixadas simetricamente na superfície refletora e um tubo reator em quartzo de 0,7 L, posicionados verticalmente no eixo do refletor. Para o processo O3-H2O2/UV foram utilizadas lâmpadas Phillips TUV (36 W, 254 nm). A corrente gasosa contendo O3 foi introduzida no reator por meio de um difusor. Para o processo foto-Fenton foram utilizadas lâmpadas Sylvania (12 W cada, 300 400 nm) e concentração de Fe(II) de 0,25 mmol/L. Em ambos os processos, solução de peróxido de hidrogênio foi adicionada durante os 30 minutos iniciais de tratamento. As amostras foram analisadas por medidas de carbono orgânico total (COT) e remoção de cor (absorbância medida em 405 nm em espectrofotômetro UV-visível). Em ambos os processos utilizou-se o planejamento experimental Doehlert, definindo os valores mínimo e máximo para cada variável adotada. No caso do processo O3- H2O2/UV (ETAPA I), foram estudados os efeitos da potência elétrica total das lâmpadas (144 432 W), concentração de H2O2 (5 30 mmol/L), concentração inicial de corante (20 100 mg/L), concentração de ozônio (10 40 mg/L) e pH (3 10). No processo foto-Fenton (ETAPA II), estudaram-se os efeitos da potência (160 480 W), concentração de H2O2 (5 30 mmol/L) e concentração inicial de corante (20 100 mg/L). Os resultados da ETAPA I indicaram que o aumento da concentração do corante, em meio ácido, aumenta a remoção de cor em 5 e 60 minutos, sugerindo a eficiência da ação via ozônio molecular sob o grupo cromóforo do corante. Os melhores resultados apresentaram remoção acima de 95% em 5 e 60 minutos de tratamento. Entretanto, para a remoção de COT em 60 minutos o processo não foi eficiente, apresentando resultado máximo de 35,6%. Na ETAPA II obtiveram-se resultados menos satisfatórios para remoção de cor se comparados aos da ETAPA I (56,1% em 5 minutos e 78% em 60 minutos de tratamento), mas melhores em relação à remoção de COT em 60 minutos atigindo 45,1% de remoção. As maiores taxas de remoção de cor foram observadas nos 5 primeiros minutos de tratamento para todos os experimentos. Experimentos complementares realizados em uma terceira etapa (ETAPA III) mostraram que a aplicação do processo O3 seguido do processo foto-Fenton permitiu resultados satisfatórios tanto para remoção de cor (97,2%), quanto para remoção de COT (69,5%). O estudo da ação do processo O3 em modo contínuo e a avaliação econômica preliminar do processo integrado O3 - foto-Fenton sugerem o potencial de aplicação do tratamento integrado a indústrias têxteis. / The textile industry generates large volumes of wastewater with high organic load, strong coloration and toxicity. In this work, the treatment of an aqueous solution containing the dye Solophenyl Yellow Arle 154% was studied by the O3-H2O2/UV and photo-Fenton processes, in order to evaluate the responses color removal after 5 minutes; color removal after 60 minutes; maximum rate of color removal; and TOC removal after 60 minutes. The experiments were carried out in the semi-batch mode with circulation using a photochemical reactor with annular coaxial radiation field, consisting of a cylindrical stainless steel support with an aluminum internal reflector with 12 lamps fixed symmetrically in the internal reflecting surface, and a quartz tube reactor of 0.7 L, positioned vertically along the axis of the reflector. For the O3- H2O2/UV process, Phillips TUV lamps (36 W, 254 nm) were used; the gas stream containing zone was introduced into the reactor through a diffuser. For the photo- Fenton process, Sylvania lamps (12 W each, 300 - 400 nm) and a concentration of Fe (II) of 0.25 mmol/L were used. In both cases, the hydrogen peroxide solution was added in the first 30 minutes of treatment. The samples were analyzed by the measurement of total organic carbon (TOC) and color removal (absorbance measured at 405 nm in a UV-visible spectrophotometer). In both cases the Doehlert experimental design was used, defining the minimum and maximum values of each variable adopted. In the case of O3-H2O2/UV process (PHASE I), the effects of the total electric power of the lamps (144 - 432 W), H2O2 concentration (5 - 30 mmol/L), initial dye concentration (20 - 100 mg/L), ozone concentration (10 - 40 mg/L), and pH (3 - 10) were studied. For the photo-Fenton process, the studied variables were: total electric power of the lamps (160 - 480 W), H2O2 concentration (5 - 30 mmol/L), and initial dye concentration (20 - 100 mg/L). The results of PHASE I indicated that the increase of dye concentration in acidic conditions increases color removal after 5 and 60 minutes, thus suggesting the efficiency of molecular ozone action upon the chromophore group of the dye. The best results showed color removal above 95% after 5 and 60 minutes of treatment. However, for the TOC removal the process was not efficient, with maximum removal after 60 minutes of only 35.6%. In PHASE II less satisfactory results for color removal were obtained in comparison with PHASE I (56.1% after 5 minutes and 78% after 60 minutes of treatment), but with higher TOC removal after 60 minutes, achieving over 45.1%. The highest color removal rates were observed within the first 5 minutes of treatment for all runs. Additional experiments carried out in PHASE III showed that the oxidation by O3 followed by the photo-Fenton process enabled to achieve suitable results for both color (97.2%) and TOC removals (69.5%). The study of the O3 process in the continuous mode and a preliminary economic evaluation suggests a high potential for the use of the integrated O3-photo-Fenton process in textile industries.

La métalloprotéine PerR (Peroxyde resistance Regulator), homodimère de 2 fois 16,5 kDa, est un facteur de la transcription. PerR est le senseur du peroxyde d'hydrogène chez plusieurs microorganismes. PerR de Bacillus subtilis a été isolée sous sa forme apo avec la présence d'un ion Zn2+ par monomère. Dans des conditions de culture non contrôlées, PerR est en partie oxydée de manière aléatoire. La spectrométrie de masse et la spectroscopie RPE nous ont permis de relier la capacité de fixation du métal régulateur (Fe2+ ou Mn2+) et l'oxydation de PerR. Notre travail a permis de mettre au point un protocole d'expression conduisant de manière reproductible à une forme totalement réduite. Ceci a permis la détermination précise de l'affinité de la protéine pour le métal régulateur et l'ADN. La forme apo-PerR-Zn a été cristallisée et cette structure révèle un site structural à zinc avec une coordination tétraédrique par les quatre cystéines de la protéine (motif Zn(Cys)4). Ce site verrouille le domaine de dimérisation, favorisant ainsi la stabilité du dimère. Le rôle structural de ce site a été confirmé par des expériences biochimiques qui mettent en évidence une réactivité faible vis-à-vis d'H2O2. Des études en spectroscopie de fluorescence ont montré des changements conformationnels de PerR en solution après métallation et fixation à l'ADN. La formation du complexe ADN-PerR a été étudiée de manière détaillée et a permis de mettre en évidence deux nucléotides et trois acides aminés essentiels dans cette interaction. Enfin, nos travaux sur la forme oxydée de PerR ont mis en évidence que le résidu 2-oxo-histidine est le marqueur biologique de l'oxydation de PerR.

Oxidation reactions are of prime importance at an industrial level and correspond to a huge market. Oxidation reactions are widely practiced in industry and are thoroughly studied in academic and industrial laboratories. Achievements in oxidation process resulted in the development of many new selective oxidation processes. Environmental protection also relies mainly on oxidation reactions. Remarkable results obtained in this field contributed to promote the social image of chemistry which gradually changes from being the enemy of nature to becoming its friend and savior. This study dealt with two aspects regarding oxidation process. The first aspect represented an experimental study for the partial oxidation of benzene to phenol using Pd membrane in the gaseous phase. The second part was a theoretical study for some of the advanced oxidation process (AOPs) which are applied for contaminant destructions in polluted waters. Niwa and coworkers reported a one step catalytic process to convert benzene to phenol using Pd membrane. According to their work, this technique will produce a higher yield than current cumene and nitrous oxide based industrial routes to phenol. A similar system to produce phenol from benzene in one step was studied in this work. Results at low conversion of benzene to phenol were obtained with a different selectivity from the reported work. High conversion to phenol was not obtained using the same arrangement as the reported one. High conversion to phenol was obtained using a scheme different from the one reported by Niwa et al1. It was found that producing phenol from benzene is not related to Pd-membrane since phenol was produced by passing all reactants over a Pd catalyst. Within the studied experimental conditions, formation of phenol was related to Pd catalyst since Pt catalyst was not capable of activating benzene to produce phenol. Other evidence was the result of a blank experiment, where no catalyst was used. From this experiment no phenol was produced. A kinetic model for the advanced oxidation process using ultraviolet light and hydrogen peroxide (UV/H2O2) in a completely mixed batch reactor has been tested for the destruction of humic acid in aqueous solutions. Known elementary chemical reactions with the corresponding rate constants were taken from the literature and used in this model. Photochemical reaction parameters of hydrogen peroxide and humic acid were also taken from the literature. Humic acid was assumed to be mainly destroyed by direct photolysis and radicals. The rate constant for the HA- reaction was optimized from range of values in the literature. Other fitted parameters were the rate constant of direct photolysis of hydrogen peroxide and humic acid. A series of reactions were proposed for formation of organic byproducts of humic acid destruction by direct photolysis and radicals. The corresponding rate constants were optimized based on the best fit within the range of available published data. This model doesn't assume the net formation of free radicals species is zero. The model was verified by predicting the degradation of HA and H2O2 for experimental data taken from the literature. The kinetic model predicted the effect of initial HA and H2O2 concentration on the process performance regarding the residual fraction of hydrogen peroxide and nonpurgeable dissolved organic carbon (NPDOC). The kinetic model was used to study the effect of the presence of carbonate/bicarbonate on the rate of degradation of NPDOC using hydrogen peroxide and UV (H2O2/UV) oxidation. Experimental data taken from literature were used to test the kinetic model in the presence of carbonate/bicarbonate at different concentrations. The kinetic model was able to describe the trend of the experimental data. The kinetic model simulations, along with the experimental data for the conditions in this work, showed a retardation effect on the rate of degradation of NPDOC due to the presence of bicarbonate and carbonate. This effect was attributed to the scavenging of the hydroxyl radicals by carbonate and bicarbonate. A kinetic model for the degradation of methyl tert-butyl ether (MTBE) in a batch reactor applying Fenton's reagent (FeII/ H2O2) and Fenton-like reagent (Feo/ H2O2) in aqueous solutions was proposed. All of the rate and equilibrium constants for hydrogen peroxide chemistry in aqueous solutions were taken from the literature. Rate and equilibrium constants for ferric and ferrous ions reactions in this model were taken from the reported values in the literature, except for the rate constant for the reaction of ferric ions with hydrogen peroxide where it was fitted within the range that was reported in the literature. Rate constant for iron dissolution was also a fitted parameter. The mechanism of MTBE degradation by the hydroxyl radicals was proposed based on literature studies. The kinetic model was tested on available experimental data from the literature which involved the use of Fenton's reagent and Fenton-like reagent for MTBE degradation. The degradation of MTBE in Fenton's reagent work was characterized to proceed by two stages, a fast one which involved the reaction of ferrous ions with hydrogen peroxide (FeII/H2O2 stage) and another, relatively, slower stage which involved the reaction of ferric ions with hydrogen peroxide (FeIII/H2O2 stage). The experimental data of MTBE degradation in the FeII/H2O2 stage were not sufficient to validate the model, however the model predictions of MTBE degradation in the FeIII/H2O2 stage was good. Also, the model was able to predict the byproducts formation from MTBE degradation and their degradation especially methyl acetate, and tert-butyl alcohol. The effect of each proposed reaction on MTBE degradation and the byproducts formation and degradation was elucidated based on a sensitivity analysis. The kinetic model predicted the degradation of MTBE for Fenton-like reagent for the tested experimental data. Matlab (R13) was used to solve the set of ordinary nonlinear stiff differential equations that described rate of species concentrations in each advanced oxidation kinetic model. Niwa, S. et al., Science 295 (2002) 105

La cellule ß pancréatique sécrète l’insuline, la seule hormone capable de diminuer la concentration en glucose plasmatique. L'insuline est sécrétée de manière régulée sous l’influence de divers stimuli dont avant tout l’élévation de la glycémie, celle-ci augmentant lors de chaque repas. Elle est donc essentielle à la préservation de l'homéostasie du glucose. Son importance est attestée par le développement du diabète sucré et de ses complications sévères et parfois mortelles lorsque sa sécrétion est supprimée ou insuffisante et/ou lorsqu'il existe un défaut de son action.La cellule ß est une cellule excitable, c'est à dire capable de moduler son potentiel membranaire très rapidement en variant certaines conductances ioniques (Dean & Matthews 1968; 1970a; 1970b). En réponse à une élévation du glucose extracellulaire, la cellule ß se dépolarise et génère des potentiels d’action qui aboutissent à une augmentation du calcium cytoplasmique induisant la libération d’insuline par exocytose. La succession des différentes étapes menant à cette sécrétion régulée d'insuline est complexe, souvent désignée sous le vocable de couplage stimulus-sécrétion. Elle commence par une augmentation de l’entrée du glucose et de son métabolisme dans la cellule ß. L’augmentation de la concentration en ATP (ou du rapport de concentrations ATP/ADP) qui en résulte, entraîne la fermeture des canaux potassiques ATP-sensibles (KATP) avec une dépolarisation partielle de la membrane. Toutefois la fermeture de ces canaux ne semble pas suffisante pour expliquer la dépolarisation membranaire observée sous l’effet du glucose et une dépolarisation supplémentaire est nécessaire pour arriver au seuil d’activation des canaux calciques voltage-dépendants ou Cav (Gilon & Rorsman, 2009). Un efflux de Cl- de la cellule ß est déclenché lors d’une stimulation au glucose (Sehlin 1978; Sehlin 1987), proportionnellement à la concentration de glucose entre 5 et 20 mM (Malaisse et coll. 2004). Une diminution de la concentration en Cl- du milieu extracellulaire (à 10 mM ou moins) réduit fortement la sécrétion d’insuline (de 70 % ou plus avec 10 et 20 mM de glucose) et affecte l'activité électrique, inhibant voire abolissant les salves de potentiel d'action d'îlots de souris (Sehlin 1978; Sehlin & Meissner, 1988). L’ion chlorure joue donc un rôle essentiel dans l'activité électrique et la sécrétion d’insuline des cellules ß sous l'effet du glucose. Les travaux qui constituent l'objet de cette thèse sont consacrés à caractériser le transport membranaire des ions Cl- dans les cellules ß ainsi que sa régulation et particulièrement le rôle d’un canal Cl- récemment identifié et cloné: l’anoctamine1 (Ano1 ou TMEM16A).Au chapitre 3, nous démontrons l’expression de transcrits d’Ano1 par transcription inverse et amplification en chaîne par polymérase (RT-PCR) chez l'homme et le rat ainsi que l’expression de la protéine par western blot et immunohistochimie chez le rat. Sur coupe de pancréas, un marquage pour Ano1 est observé dans les îlots et dans les cellules acinaires du pancréas exocrine. La spécificité du marquage est attestée par sa disparition lors de l'addition d’un peptide compétiteur (Ano1 exogène). Nous avons démontré en patch-clamp la présence d’Ano1 actif dans la membrane des cellules ß: i) Nous avons observé des courants typiques d'Ano1 dans des patchs de cellules ß de rat entières et excisés inside-out en présence de Ca2+ intracellulaire: à 1 µM, le courant Cl- est rectifiant sortant et à 2 µM il devient presque linéaire. ii) La relation amplitude unitaire-voltage des courants Cl- unitaires activés par le Ca2+ est linéaire et montre une conductance de 8,37 pS, correspondant exactement à la conductance décrite pour Ano1. iii) Les perméabilités relatives des anions monovalents sont NO3- (1.83 ± 0.10) > Br- (1.42 ± 0.07) > Cl- (1.0), compatibles avec celles d'Ano1. iv) Ces courants sont quasi abolis par des anticorps Ano1-bloquants ou par deux inhibiteurs d’Ano1, 2-(5-éthyl-4-hydroxy-6-méthylpyrimidine-2-ylthio)-N-(4-(4-méthoxyphényl)thiazol-2-yl)acétamide (T-AO1) et acide tannique (TA). Ayant démontré la présence d'Ano1 fonctionnels au niveau de la membrane des cellules ß, nous avons investigué l'implication d'Ano1 dans la dépolarisation membranaire induite par le glucose. Cette étude a été réalisée en patch-clamp perforé sur des cellules ß d'îlots entiers de souris et des cellules ß dispersées de rat et de souris stimulées par le glucose. Les inhibiteurs d'Ano1 (T-AO1 et TA) induisent une forte diminution de la fréquence des potentiels d'action lors d'une stimulation par 16.7 mM de glucose (au moins 87 % sur cellules dispersées) et une repolarisation partielle du potentiel membranaire avec le T-AO1. Ces inhibiteurs abolissent ou inhibent fortement l'augmentation de sécrétion d'insuline d'îlots de rat induite par 8.3 mM et 16.7 mM de glucose. Des anticorps Ano1-bloquants abolissent également l'incrément de sécrétion d'insuline provoqué par 16.7 mM de glucose. Un traitement combiné avec du bumétanide (inhibant l'entrée de Cl- dans la cellule par NKCC1/2) et de l'acétazolamide (inhibant l'anhydrase carbonique V mitochondriale produisant du HCO3- intracellulaire durant le métabolisme du glucose) dans un milieu contenant 20 mM de Cl- et sans HCO3- provoque une réduction de 65 % de l'amplitude des potentiels d'action (AP) avec une repolarisation de 15 mV de leur pic sur des cellules ß dispersées de rat, confirmant l'importance de ces anions dans la régulation des oscillations du potentiel membranaire sous l'effet du glucose. Cette étude démontre que l'ouverture d'Ano1 est nécessaire pour permettre les oscillations du potentiel membranaire stimulées sous l'effet du glucose et la sécrétion d'insuline.Au chapitre 4, nous avons étudié les effets de l'H2O2 sur le canal anionique sensible au gonflement cellulaire (appelé VRAC pour volume-regulated anion channel) dans les cellules ß de rat et de la lignée de rat BRIN-BD11. L'H2O2 produit par une ou plusieurs NAD(P)H oxidase(s) (NOX) a récemment été proposé d'agir, dans plusieurs types cellulaires, comme le signal médiateur de l'activation de ces canaux activés lors du gonflement cellulaire. L'H2O2 exogène (100 à 200 µM) à une concentration de glucose basale (1,1 à 2,8 mM) stimule la sécrétion d'insuline. L'inhibiteur de VRAC, 5-nitro-2-(3-phénylpropylamino)-benzoate (NPPB), également inhibiteur d'Ano1, inhibe la réponse sécrétoire à l'H2O2 exogène. Dans des expériences de patch-clamp, nous montrons que l'H2O2 exogène stimule l’ouverture de VRAC, induisant une dépolarisation du potentiel membranaire et un courant anionique, abolis par le NPPB. L'exposition des cellules BRIN-BD11 à un milieu hypotonique (200 mosmol/l) provoquait un gonflement cellulaire suivi d’un retour vers le volume initial (en 10-15 min) suite à l’activation du canal VRAC, et une augmentation détectable du niveau intracellulaire de dérivés réactifs de l'oxygène (ROS) mise en évidence par l'oxydation du colorant fluorescent 5-(et-6)-chlorométhyl-2',7'-dichlorodihydrofluorescéine (CM-H2DCF). Cette production de ROS est abolie par le chlorure de diphénylèneiodonium (DPI), un inhibiteur de flavoprotéines dont les NOX et certaines protéines de la chaîne respiratoire mitochondriale. Les inhibiteurs de NOX tels le DPI et la plumbagine inhibaient presque totalement l’incrément de sécrétion d'insuline provoqué par l'exposition des cellules BRIN-BD11 au milieu hypotonique. Une préincubation avec les deux drogues suivantes abolit quasiment la sécrétion d'insuline tant induite par l'hypotonicité que basale: i) N-acétyl-L-cystéine (NAC), un précurseur du glutathion qui sert d'antioxydant général et ii) l'acide bétulinique, un composé qui abolit presque totalement l'expression NOX4. Comme le NPPB, chacun de ces inhibiteurs (DPI, plumbagine, préincubation avec NAC ou de l'acide bétulinique) réduit fortement ou abolit la régulation du volume cellulaire observée suite à un choc hypotonique, fournissant une preuve indépendante que l'activation de VRAC est médiée par l'H2O2. L'ensemble de ces données suggère que l'H2O2 produit par une ou plusieurs NOX joue un rôle critique dans la réponse insulino-sécrétoire des cellules ß de la lignée de rat BRIN-BD11 et des cellules ß de rat à l'hypotonicité extracellulaire, via une dépolarisation produite par l'activation de VRAC et une sortie d'anions. L'inhibition de cette dépolarisation produite sous l’effet de l'H2O2 et de l’hypotonicité, ainsi que de la régulation du volume cellulaire observée suite à un choc hypotonique par les inhibiteurs d'Ano1 T-AO1 et TA (100 µM) suggèrent qu'Ano1 est associé à ce canal VRAC ou le constitue ou tout au moins en constitue une sous-unité. Le mécanisme exact entraînant l’ouverture d’Ano1 sous l’effet du glucose n’est pas élucidé. Toutefois à la suite des travaux de Llanos (Llanos et coll. 2015), nous suggérons la séquence d'événements suivante: outre la fermeture des canaux KATP, le métabolisme du glucose produit des ROS qui oxydent et ouvrent RyR2, libérant du Ca2+ des stocks intracellulaires à des endroits localisés près de la membrane cellulaire et d’Ano1 qui est ainsi activé. En conclusion, nos études démontrent que i) l'efflux de Cl- (dépolarisant) de cellules ß murines sous l'effet du glucose dépend de l’ouverture du canal Cl- activé par le calcium intracellulaire (CaCC) Ano1. Le canal Ano1 est activé sous l’effet du glucose et son activation est requise pour induire les potentiels d’action et l'entrée de Ca2+ dans la cellule ß, nécessaires à la libération d’insuline. L'ouverture d'Ano1 semble donc responsable des oscillations du potentiel membranaire en phase active avec potentiels d'action et sa fermeture pourrait participer à la repolarisation des phases silencieuses. ii) l'H2O2 produit par une ou plusieurs NAD(P)H oxydase(s) sous l’effet du gonflement cellulaire, ou du glucose (Pi et coll. 2007, Leloup et coll. 2009), ou encore ajouté de manière exogène est nécessaire à l’activation du canal anionique sensible au gonflement cellulaire VRAC. L'ouverture de VRAC s'accompagne d'une sortie d'anions, dépolarise les cellules ß de la lignée de rat BRIN-BD11 et de rat et provoque une stimulation de la sécrétion d’insuline. Ano1 pourrait être associé à VRAC, le constituer ou en constituer une sous-unité. Le mécanisme déclenchant l'ouverture d'Ano1 reste à élucider. / Doctorat en Sciences biomédicales et pharmaceutiques (Médecine) / info:eu-repo/semantics/nonPublished

Les effluents industriels sont constitués de molécules de natures très diverses, plus ou moins réfractaires aux classiques traitements biologiques. Les normes de rejets évoluant régulièrement vers des contraintes de plus en plus sévères, il semble aujourd'hui nécessaire de proposer des solutions complémentaires pour atteindre de hauts rendements d'épuration. Le premier procédé mis en oeuvre dans ce travail est l'adsorption sur charbon actif. Le caractère novateur de cette technique se situe dans l'utilisation de charbons actifs fabriqués à partir de boues de stations d'épuration d'eaux usées. La seconde méthode est un procédé hybride innovant combinant adsorption et photocatalyse avec TiO2. Les eaux industrielles ciblées sont les effluents colorés, représentés par la tartrazine, et les effluents phénolés représentés par le phénol, l'acide p-hydroxybenzoïque, le p-chlorophénol er le p-nitrophénol. Pour traiter par adsorption les eaux chargées en phénols, plusieurs charbons actifs commerciaux et six charbons de boues ont été utilisés. Il ressort de cette première étude que, malgré leurs faibles surfaces spécifiques, certains charbons de boues présentent des performances très satisfaisantes. Le procédé séquentiel combinant adsorption et photocatalyse a été réalisé avec plusieurs matériaux: un tissu Ahlstrom contenant du charbon et du TiO2, un charbon actif avec dépôt de TiO2 par MOCVD puis un mélange de charbon actif et TiO2 en poudre. Des résultats prometteurs ont été obtenus pour dégrader la tartrazine, en particulier avec le TiO2 déposé sur charbon actif montrant que la proximité de sites d'adsorption et photocatalytique améliore les performances de l'oxydation / In order to explore a new sequential process for water treatment its two steps, adsorption on activated carbon and in situ photocatalytic oxidative regeneration, were investigated successively. Several commercial activated carbons (AC) and sewage sludge based activated carbons (SBAC) were tested with several phenols and one dye as pollutants. Despite low BET surface SBAC exhibits convenient adsorption properties. Photocatalysis on TiO2 was carried out with several materials to achieve activated carbon adsorption- egeneration process: a multilayer tissue with fixed granular AC and TiO2 on a sheet, a composite with TiO2, CVD deposited on AC, and AC-TiO2 powder mixture for comparison. Promising results were obtained especially with TiO2 deposited on AC proving the vicinity of adsorption and photocatalytic sites to be beneficial