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Tratamento de efluente têxtil através de processos redox e separação com membranas combinados / Treatment of textile wastewater by combination of redox and membrane separation processesAlvarenga, Rodrigo Neder 14 August 2009 (has links)
O processamento têxtil gera grande quantidade de despejos altamente poluidores, contendo valores elevados de carga orgânica, cor acentuada e compostos químicos tóxicos ao homem e ao meio ambiente. Os efluentes têxteis apresentam uma variação muito grande na sua composição devido aos vários tipos de corantes e produtos químicos utilizados e isto faz o seu tratamento ser um problema complexo. Devido a estas implicações, novas tecnologias têm sido buscadas para a degradação ou imobilização destes compostos em efluentes têxteis dentre os quais a combinação de processos oxidativos avançados, redutivo e separação por membranas. Os processos de separação por membranas têm sido cada vez mais aplicados para separação, purificação e concentração de constituintes industriais, principalmente pelo desenvolvimento e eficiência da técnica e redução de custos com o passar dos anos. O processo redutivo utilizando Fe0 é bastante promissor, em função do custo relativamente baixo do ferro metálico e da sua elevada efetividade na degradação de contaminantes ambientais, sendo que após a oxidação do Fe0 a íons Fe2+ e Fe3+ estes íons podem ser aproveitados em sequência nos Processos Oxidativos Avançados (POAs). Os processos oxidativos avançados são tecnologias extremamente eficientes para destruição de compostos orgânicos de difícil degradação. Podem ser consideradas tecnologias limpas, pois não há a formação de subprodutos sólidos e nem a transferência de fase dos poluentes. Os POAs são baseados na geração de radicais fortemente oxidativos, principalmente o radical hidroxila (HOo), que destroem inúmeros compostos de maneira rápida e pouco seletiva, quando comparado aos processos convencionais, conduzindo a mineralização parcial ou completa dos contaminantes. Com o objetivo de estudar o efeito destes processos na melhoria do efluente têxtil foi utilizado um efluente de uma indústria têxtil de grande porte do interior de São Paulo. Ao ser coletado, este efluente foi caracterizado e submetido à permeação por membranas de microfiltração (0,45 μm). Este tratamento possibilitou a redução de 37,7 % do COT e 40,9 % da Área Espectral (200-800 nm) em comparação com o efluente original. O efluente oriundo do tratamento com membranas foi submetido, através de planejamento de experimentos, aos processos oxidativos avançados do tipo foto-Fenton e foto-Fenton avançado (utilizando Fe0) visando à melhoria para despejo ou reúso deste efluente. Na melhor condição de reação foi possível alcançar uma redução de aproximadamente 73,0 % em COT e 93,0 % em área espectral após uma hora de reação para os dois tipos de POAs. A combinação das tecnologias de membranas e processos oxidativos avançados mostrou-se extremamente positiva quanto à melhoria da deste efluente têxtil, possibilitando a redução em torno de 83,0 % do COT e 95,0 % da área espectral. / The textile manufacturing generates large amounts of highly polluting sewage containing high levels of organic load, color and chemical compounds toxic to human beings and to the environment. This textile wastewater has a great variation in its composition due to various types of dyes and chemicals used. All these considerations make the textile wastewater treatment a complex problem. Due to these implications, new technologies have been studied for degradation or immobilization of these compounds in textile wastewater among which the combination of advanced oxidative, reductive and separation with membranes processes. The separation processes with membranes have been increasingly applied for separation, purification and concentration of industrial components, mainly development in technology and efficient cost savings over the years. The reductive process using Fe0 is very promising because of the relatively low cost of metallic iron and its high effectiveness in the degradation of environmental contaminants. After the oxidation of Fe0 to Fe2+ and Fe3+ these ions can be used in sequence in the Advanced Oxidative Process (AOPs). The advanced oxidative process technologies are extremely effective for degradation of organic compounds with difficult degradation. It can be considered as a clean technology, because there is no formation of solid subproducts, neither the phase transfer of pollutants. The AOPs are based on the generation of highly oxidative radicals, particularly hydroxyl radical (HOo), which destroys many compounds to a rapid and low selective way compared with conventional process of treatment, leading to partial or complete mineralization of contaminants. A wastewater from a large textile industry in São Paulo was used in order to study the effect of these processes in the improvement of textile wastewater quality. Firstly, the wastewater was characterized and subjected to permeation by microfiltration membrane (0.45 μm). This treatment allowed a reduction of 37.7 % of TOC and 40.9 % of spectral area (200-800 nm) compared to the original wastewater. The wastewater from the treatment with membranes was subjected, through design of experiments, the advanced oxidative processes of the type photo-Fenton and advanced photo-Fenton (using Fe0) aiming to improve the disposal or to reuse of wastewater. In the best experimental condition it was achieved a 73 % in TOC and 93 % in spectral area reduction after one hour of reaction for both types of AOPs. The membrane technologies and advanced oxidative combination process proved to be extremely positive on the textile wastewater quality improvement, resulting in a reduction of around 83 % of TOC and 95 % of spectral area.
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Tratamento de efluente têxtil através de processos redox e separação com membranas combinados / Treatment of textile wastewater by combination of redox and membrane separation processesRodrigo Neder Alvarenga 14 August 2009 (has links)
O processamento têxtil gera grande quantidade de despejos altamente poluidores, contendo valores elevados de carga orgânica, cor acentuada e compostos químicos tóxicos ao homem e ao meio ambiente. Os efluentes têxteis apresentam uma variação muito grande na sua composição devido aos vários tipos de corantes e produtos químicos utilizados e isto faz o seu tratamento ser um problema complexo. Devido a estas implicações, novas tecnologias têm sido buscadas para a degradação ou imobilização destes compostos em efluentes têxteis dentre os quais a combinação de processos oxidativos avançados, redutivo e separação por membranas. Os processos de separação por membranas têm sido cada vez mais aplicados para separação, purificação e concentração de constituintes industriais, principalmente pelo desenvolvimento e eficiência da técnica e redução de custos com o passar dos anos. O processo redutivo utilizando Fe0 é bastante promissor, em função do custo relativamente baixo do ferro metálico e da sua elevada efetividade na degradação de contaminantes ambientais, sendo que após a oxidação do Fe0 a íons Fe2+ e Fe3+ estes íons podem ser aproveitados em sequência nos Processos Oxidativos Avançados (POAs). Os processos oxidativos avançados são tecnologias extremamente eficientes para destruição de compostos orgânicos de difícil degradação. Podem ser consideradas tecnologias limpas, pois não há a formação de subprodutos sólidos e nem a transferência de fase dos poluentes. Os POAs são baseados na geração de radicais fortemente oxidativos, principalmente o radical hidroxila (HOo), que destroem inúmeros compostos de maneira rápida e pouco seletiva, quando comparado aos processos convencionais, conduzindo a mineralização parcial ou completa dos contaminantes. Com o objetivo de estudar o efeito destes processos na melhoria do efluente têxtil foi utilizado um efluente de uma indústria têxtil de grande porte do interior de São Paulo. Ao ser coletado, este efluente foi caracterizado e submetido à permeação por membranas de microfiltração (0,45 μm). Este tratamento possibilitou a redução de 37,7 % do COT e 40,9 % da Área Espectral (200-800 nm) em comparação com o efluente original. O efluente oriundo do tratamento com membranas foi submetido, através de planejamento de experimentos, aos processos oxidativos avançados do tipo foto-Fenton e foto-Fenton avançado (utilizando Fe0) visando à melhoria para despejo ou reúso deste efluente. Na melhor condição de reação foi possível alcançar uma redução de aproximadamente 73,0 % em COT e 93,0 % em área espectral após uma hora de reação para os dois tipos de POAs. A combinação das tecnologias de membranas e processos oxidativos avançados mostrou-se extremamente positiva quanto à melhoria da deste efluente têxtil, possibilitando a redução em torno de 83,0 % do COT e 95,0 % da área espectral. / The textile manufacturing generates large amounts of highly polluting sewage containing high levels of organic load, color and chemical compounds toxic to human beings and to the environment. This textile wastewater has a great variation in its composition due to various types of dyes and chemicals used. All these considerations make the textile wastewater treatment a complex problem. Due to these implications, new technologies have been studied for degradation or immobilization of these compounds in textile wastewater among which the combination of advanced oxidative, reductive and separation with membranes processes. The separation processes with membranes have been increasingly applied for separation, purification and concentration of industrial components, mainly development in technology and efficient cost savings over the years. The reductive process using Fe0 is very promising because of the relatively low cost of metallic iron and its high effectiveness in the degradation of environmental contaminants. After the oxidation of Fe0 to Fe2+ and Fe3+ these ions can be used in sequence in the Advanced Oxidative Process (AOPs). The advanced oxidative process technologies are extremely effective for degradation of organic compounds with difficult degradation. It can be considered as a clean technology, because there is no formation of solid subproducts, neither the phase transfer of pollutants. The AOPs are based on the generation of highly oxidative radicals, particularly hydroxyl radical (HOo), which destroys many compounds to a rapid and low selective way compared with conventional process of treatment, leading to partial or complete mineralization of contaminants. A wastewater from a large textile industry in São Paulo was used in order to study the effect of these processes in the improvement of textile wastewater quality. Firstly, the wastewater was characterized and subjected to permeation by microfiltration membrane (0.45 μm). This treatment allowed a reduction of 37.7 % of TOC and 40.9 % of spectral area (200-800 nm) compared to the original wastewater. The wastewater from the treatment with membranes was subjected, through design of experiments, the advanced oxidative processes of the type photo-Fenton and advanced photo-Fenton (using Fe0) aiming to improve the disposal or to reuse of wastewater. In the best experimental condition it was achieved a 73 % in TOC and 93 % in spectral area reduction after one hour of reaction for both types of AOPs. The membrane technologies and advanced oxidative combination process proved to be extremely positive on the textile wastewater quality improvement, resulting in a reduction of around 83 % of TOC and 95 % of spectral area.
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Synthèse de nanoparticules d'or supportées sur oxyde mésoporeux : Application à l'oxydation de composés organiques volatils modèles / Synthesis of gold nanoparticles supported on mesoporous oxides : Application to the oxidation of volatile organic compoundsBaïliche, Zohra 31 October 2013 (has links)
L’obtention de nanoparticules d’or nécessite le contrôle de nombreux paramètres et la compréhension du mode d’interaction entre l’or et le support. Pour cela, le choix du support est très important. Le premier volet de la thèse concerne la préparation contrôlée des catalyseurs à base d’or supporté sur les oxydes mésoporeux réductibles TiO₂, CeO₂ et Fe₂O₃ synthétisés via deux stratégies Soft et hard template en utilisant respectivement comme agents structurants le tribloc copolymère (Pluronic 123) et la silice mésoporeuse SBA-15. Les différentes techniques de caractérisation mettent bien en évidence que le taux de dépôt de l’or dépend de la concentration initiale de HAuCl₄, de la méthode de préparation (DPU, DP NaOH), de la teneur en or visée et de la nature du support ; Ces résultats sont à relier à la spéciation des espèces or en solution en fonction du pH final de la solution. Les taux de dépôt de l’or sont plus importants sur CeO₂ et ceci quelle que soit la teneur en or visée dans ce travail. Une dispersion très élevée est obtenue (la taille moyenne des particules d’or est de 2nm) sur les catalyseurs à 1% et 2%Au/CeO₂ préparés par la méthode DPU et calcinés à 400°C. Le deuxième volet de cette étude concerne l’oxydation en phase gaz d’une molécule organique modèle le toluène et l’oxydation en phase liquide d’une molécule organique modèle le phénol par des réactions de type Fenton et photo Fenton. Dans l’oxydation du toluène en phase gazeuse, les catalyseurs à base d’or supportés sur oxydes mésoporeux sont totalement sélectifs en CO₂ et H₂O. Les performances catalytiques dépendent des conditions de synthèse des catalyseurs et de la nature de l’oxyde utilisé ; le catalyseur 1%Au/CeO₂ est très actif et très stable au cours de quatre cycles successifs et au cours du temps. L’oxydation en phase liquide d’une molécule organique modèle le phénol par des réactions de type Fenton et photo Fenton a été effectuée sur les catalyseurs FeSBA-15 synthétisés via différentes stratégies : introduction du fer par voie postsynthétique et par voie hydrothermale en milieu faiblement et fortement acide respectivement à pH=6 et pH=3. Les performances catalytiques dépendent du rapport Si/Fe et de la taille des particules des espèces de fer, la taille des particules étant directement liée à la stratégie de synthèse des catalyseurs. Le catalyseur FeSBA-15(Si/Fe=60) synthétisé à pH=6 est un candidat potentiel dans la dégradation de polluants organiques par procédé Fenton et photo-Fenton en milieu neutre. / Well dispersed gold nanoparticles are the key to obtain an active gold catalyst. Obtaining gold nanoparticles requires control of many parameters and understanding of the interaction mode between gold and the support. For this reason the choice of the support is very important. The first part of this thesis concerns the controlled preparation of gold catalysts supported on reducible mesoporous oxides TiO₂, CeO₂ and Fe₂O₃ synthesized via two strategies Soft and Hard template using respectively. triblock copolymer (Pluronic 123) and mesoporous silica SBA-15 as template. This study clearly shows that the gold loading depends on the initial concentration of HAuCl₄, the method of preparation (DPU DP NaOH), theoretical gold content and the nature of the support. These results are to relate to the gold speciation which is a function of pH of the solution. The gold loading is higher on CeO₂ than on TiO₂ and Fe₂O₃ whatever the theoretical gold content. Very high gold dispersion is obtained (the gold particle size is 2 nm) on 1wt% and 2wt% Au/CeO₂ prepared by DPU and calcined at 400°C. The second part of this study concerns the toluene oxidation in the gas phase on Au/mesoporous oxide catalysts and the Fenton and photo-Fenton degradation of phenolic aqueous solutions by H₂O₂ on FeSBA-15 catalysts prepared following different synthesis routes, direct synthesis by adjusting pH at 3 and 6 and with post synthesis procedure. In the toluene oxidation in the gas phase Au/mesoporous oxide catalysts are totally selective for CO₂ and H₂O. The catalytic performances depend on the synthesis conditions of catalysts and the support; the 1wt% Au/CeO₂ catalyst is very active and exhibits a long-term stability. In the Fenton and photo-Fenton degradation of phenolic aqueous solutions the catalytic performances depend on the Si/Fe ratio and the particle size of the iron species, the particle size being directly related to the synthesis strategy of the catalysts. The catalyst FeSBA-15 (Si/Fe = 60) synthesized at pH = 6 is a potential candidate in the degradation of organic pollutants by Fenton and photo-Fenton process in neutral medium. / م لخصمسقني لمعلا يف هذه ةحورطألا ىلإ نيئزج:OiT 2ب وا سطة OeC 2و , Fe2O ي خ تص الاول ال ق سم ب تح ض يرمح فزات من ال ذهبن وع من م يزوب ري ة ب مواد مدعم 3ان واع مخ ت لف ال تح ض ير. ت شخ يص ف ي ال م س ت عم لة ال ت ق ن يات مخ ت لفت ب ين ال مح ضرة ل مح فزات انال دعم ط ب ي عة ك ذا و ال مح فز ت ح ض ير وطري قة HAuCl ت ر سب معدل ي ت ع لق ل ذه با ت رك يز ع لى 4ي ع ضو جزيء و سطغازي enèuloT أك سدة ف ي ال مواد هذه ب تط ب يق ي ت ع لق ال ثان ي ال ق سم ف يال مح فز ت ح ض ير Ò طرق ك ذا و ل ت فاعل هذا ع لى ال مؤث رة ل عوامل ب درا سة ق م نا سال فا ال مذك ورة ل لمح فزات ال ف عال ية ع لان واع مخ ت لف ب وا سطة FeSBA- ي ع ضو جزيء lonehP ت فاعل ب وا سطة notneF سائ ل و سط ف ي وعمن 51 ن مح فزات ع لىوHp ال و سط Si/Fe قلعتي ةبسنب FeSBA- ريضحتلا.ادأء 1515FeSBA-15, Fenton, Phenol, Toluène, TiO و 2 CeO2, Fe2O3, SBA- ال ك لمات ال م ف تاح ية ׃م يزوب وري ة ,
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Procédés de Fenton et photo-Fenton homogène et hétérogène : impact d’un agent complexant du fer, l’acide éthylènediamine-N,N’-disuccinique (EDDS) / Homogeneous and heterogeneous Fenton and photo-Fenton processes : impact of iron complexing agent ethylenediamine-N,N'-disuccinic acid (EDDS)Huang, Wenyu 25 May 2012 (has links)
Dans cette étude nous avons utilisé le bisphénol A (BPA) comme polluant modèle pour analyser l’efficacité des différents processus de Fenton et photo-Fenton mis en place. Dans un premier temps nous avons étudié le processus de Fenton en présence du complexe Fe(III)-EDDS utilisé comme source de fer. Différents paramètres physico-chimiques (concentrations en H2O2, Fe(III)-EDDS, O2 et le pH) ont été testés afin d’optimiser l’efficacité du système en termes de dégradation du BPA. Parallèlement, le même type d’étude a été mené en présence de lumière (de 300 à 450 nm) afin d’étudier le processus de photo-Fenton. Dans les 2 cas nous avons mis en évidence un effet du pH peu commun puisque la dégradation de BPA est plus rapide et importante plus le pH est élevé dans une gamme allant de 3,0 à 9,0. Dans le but de comprendre le mécanisme mis en jeu des expériences d’inhibition de radicaux (·OH et HO2●/O2●-) ont été réalisées. Une des conclusions importantes de ce travail est que dans les deux systèmes le complexe Fe(III)-EDDS joue un rôle très positif pour la dégradation du BPA. De plus, nous avons également montré que ces processus étaient très efficaces pour des pH proches de la neutralité et faiblement basiques. La comparaison avec d’autres complexant du fer (EDTA, citrate, oxalate) montre qu’en présence du complexe Fe(III)-EDDS nous obtenons l’efficacité la plus importante. Ce résultat et le fait que les processus soient très efficaces à pH neutre ou faiblement basiques montrent que le complexe Fe(III)-EDDS est vraiment une source de fer très prometteuse dans les processus de Fenton et photo-Fenton. Dans une troisième partie nous avons regardé l’effet d’EDDS dans un système hétérogène en présence de Goethite comme source de fer. Dans ce chapitre il a été mis en évidence que l’EDDS inhibe le processus de Fenton, EDDS s’adsorbe fortement à la surface et limite la réactivité de H2O2 avec la surface de la Goethite. Par contre dans le processus de photo-Fenton, EDDS augmente l’efficacité de dégradation du BPA à pH proche de la neutralité et à faible concentration en H2O2. / In this study we used the bisphenol A (BPA) as a model pollutant to analyse the efficiency of the Fenton and photo-Fenton processes. In the first part of the thesis, we studied the Fenton process in the presence of the complex Fe(III)-EDDS used as iron source. Different physicochemical parameters (concentrations of H2O2, Fe(III)-EDDS, O2 and pH) were tested with the goal to optimized the efficiency of the system in terms of BPA degradation. In the same time, the same kind of experiments were performed in the presence of light (emission from 300 to 450 nm) to study the photo-Fenton process. In the two cases (Fenton and photo-Fenton), we observed a strong and not usual pH effect. Indeed, the degradation of BPA is faster and more important when the pH is higher in the range between 3.0 and 9.0. To understand the mechanisms involved in such processes, some inhibition experiments of radicals (·OH and HO2●/O2●-) were performed. One of the most important conclusion of this research work is that the Fe(III)-EDDS complex plays a very positive role for the degradation of BPA. Moreover, in the presence of Fe(III)-EDDS the Fenton and photo-Fenton processes are very efficient in neutral and slightly basic pH. The comparison with other iron complexes (EDTA,citrate, oxalate) shows that in the presence of Fe(III)-EDDS complex we obtained the better efficiency for the degradation of BPA. This result and the fact that Fe(III)-EDDS is efficient until pH 9.0 show that Fe(III)-EDDS complex is really a promising iron source for the Fenton and photo-Fenton processes. In a third part, we studied the effect of EDDS in a heterogeneous system in the presence of Goethite as an iron source. In this chapter, we demonstrated that the presence of EDDS is detrimental for the Fenton process and leads to an inhibition of the process. In fact, EDDS is strongly adsorbed at the surface of the Goethite and avoid the reactivity of H2O2 at the Goethite surface. On the contrary, in the photo-Fenton process EDDS increases the efficiency of the BPA degradation for pHs near 7.0 and at low H2O2 concentrations.
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Procédé photo-Fenton hétérogène pour l'élimination des micropolluants à très faible concentration de la rivière Meurthe / Heterogeneous photo-fenton process for removal of micropollutants at very low concentration from Meurthe riverAyoub, Hawraa 27 March 2018 (has links)
Ce travail de thèse concerne le développement de catalyseurs Fe/Faujasite afin de dégrader un cocktail de micropolluants provenant d’une eau réelle de rivière dans la Meurthe (France) avec le procédé photo-Fenton hétérogène. Les micropolluants étudiés appartiennent à 4 grandes familles : des principes actifs pharmaceutiques, des produits de soins cosmétiques, des perturbateurs endocriniens, et des composés perfluorés. Pour la première fois, dans cette thèse, la dégradation d’un mélange de 21 micropolluants à l’état de traces (2 – 80 ng/L) provenant d’une réelle eau de rivière non-dopée a été effectuée. Cependant, le fait de travailler avec des concentrations très faibles en polluants reste un challenge notamment en ce qui concerne les aspects de chimie analytiques. Ce travail de thèse est donc divisé en deux grandes parties. Dans un premier temps, il a été nécessaire de trouver la meilleure eau réelle contenant un nombre élevé de micropolluants de différentes natures à des concentrations de l’ordre de quelques ng/L mais inférieures à 100 ng/L. Pour cela différentes campagnes de prélèvement ont été effectuées dans les deux principales rivières de la région Lorraine, la Meurthe et la Moselle, en différents lieux et différentes périodes de l’année. L’eau provenant du site de Moulin Noir a été choisie. Dans une deuxième partie, nous avons développé des catalyseurs fer/Faujasite pour pouvoir tester leur efficacité pour la dégradation des micropolluants provenant du site de Moulin Noir par le procédé photo-Fenton hétérogène. Dans une étape intermédiaire, l’optimisation des paramètres opératoires du procédé photo-Fenton avec nos catalyseurs a été effectuée en utilisant deux macropolluants modèles, phénol et diclofenac / Twenty one 21 micropollutants including pharmaceuticals, personal cares product, endocrine disruptors and perfluorinated compounds presenting at ng/L in the real water of Meurthe river, were successfully quantified and removed using heterogeneous photo-Fenton process. To achieve this goal, an analytical-catalytic methodology was developed and the work steps were performed linked together in a cycle-like manner. The use of the sensitive and efficient multi-residual SPE-LC-MS/MS analytical method allowed us to analyze and quantify the mixture of micropollutants present in a complex matrix during 3 periods of the year with different weather conditions, from 5 sampling sites. Results showed that the highest concentrations of most of the present micropollutants are observed in October at ng/L, Moulin Noir sampling site found to contain the largest number and type of these pollutants, the WWTP was not efficient in the removal of the micropollutants present in water and the drinking water used from tab was totally safe from micropollutants. The calculation of the fluxes and estimation of the mass balance at the rivers confluence confirmed the good precision and reliability of our measurement methodology, and specify the most suitable site for water to be taken from to be used in the removal tests which was Moulin Noir. Having the appropriate water sample, an efficient iron impregnated Faujasite catalyst was developed and used in a photo-Fenton process for the micropollutant removal tests. After characterization and optimization of the different experimental factors using the 2 model macropollutants, phenol and diclofenac, the real tests were performed on real water samples from Moulin Noir. The results demonstrated the good efficiency of the photo-Fenton process with the cocktail of 21 micropollutants. Except for sulfamethoxazole and PFOA, the concentrations of all the other micro-contaminants became lower than the limit of quantification of the LC-MS/MS after 30 minutes or 6 hours of photo-Fenton treatment depending on their initial concentrations under the effect of both adsorption and Fenton mechanisms. Comparing the photo-Fenton process to heterogeneous photocatalytic degradation over TiO2, Faster micropollutants removal occurred with the zeolite
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Dégradation des pesticides chlortoluron, carbofurane et bentazone en milieux aqueux par les procédés d'oxydation avancéeKesraoui-Abdessalem, Aida 12 December 2008 (has links) (PDF)
L'utilisation du procédé d'oxydation avancée électrochimique : procédé électro-Fenton est un moyen simple et économique d'obtention des radicaux hydroxyles (OH*) fortement oxydantes. Au cours de ce travail les radicaux ont été utilisés pour la dégradation du chlortoluron, du carbofurane et du bentazone en solution aqueuse. La méthodologie de la recherche expérimentale a été utilisée pour étudier l'influence de quelques paramètres (concentration du chlortoluron, l'intensité du courant et la durée du traitement.) sur la vitesse de disparition et pour déterminer les conditions optimales de minéralisation. L'évolution de la concentration des pesticides en fonction du temps de traitement montre une cinétique de pseudo premier ordre (kabs = 4,92 × 109, 3.24 × 109 et 2.63 × 109 M-1 s-1 respectivement pour le chlortoluron, le carbofurane et le bentazone). Dans nos conditions expérimentales optimales (I = 300 mA, [pesticide]0 = 0,125 mM et t = 8 h), nous obtenons un taux de minéralisation supérieur à 90% pour les trois pesticides. Dans le cas des molécules étudiées, il a été montré que le taux de minéralisation par le procédé photo-Fenton (UV/Fe3+/H2O2) est fonction des doses des réactifs utilisés et de la concentration initiale des pesticides à traiter. Une comparaison des performances de minéralisation par les différents procédés étudiés (électro-Fenton (BDD), électro-Fenton (PT), oxydation anodique et photo-Fenton) a montré que les procédés photo-Fenton et électro-Fenton (BDD) permettent d'atteindre des taux de minéralisation très importants (˜ 90% au bout de 2 h). La comparaison du coût du traitement montre que le procédé photo-Fenton coûte beaucoup plus chère que le procédé électro-Fenton (BDD). Le plasma d'air humide a été utilisé pour la dégradation du chlortoluron. Différents catalyseurs (Fe2+, Fe3+ et TiO2) ont été étudiés pour améliorer les performances du glidarc. La combinaison entre TiO2 et Fe2+ permet d'aboutir à 96% de la dégradation du chlortoluron au bout de 3h
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Dégradation des pesticides chlortoluron, carbofurane et bentazone en milieux aqueux par les procédés d'oxydation avancée / Degradation of pesticides chlortoluron, carbofuran and bentazone in aqueuos medium by advanced oxidation processesKesraoui-Abdessalem, Aïda 12 December 2008 (has links)
L’utilisation du procédé d'oxydation avancée électrochimique : procédé électro-Fenton est un moyen simple et économique d’obtention des radicaux hydroxyles (OH•) fortement oxydantes. Au cours de ce travail les radicaux ont été utilisés pour la dégradation du chlortoluron, du carbofurane et du bentazone en solution aqueuse. La méthodologie de la recherche expérimentale a été utilisée pour étudier l’influence de quelques paramètres (concentration du chlortoluron, l’intensité du courant et la durée du traitement.) sur la vitesse de disparition et pour déterminer les conditions optimales de minéralisation. L’évolution de la concentration des pesticides en fonction du temps de traitement montre une cinétique de pseudo premier ordre (kabs = 4,92 × 109, 3.24 × 109 et 2.63 × 109 M-1 s-1 respectivement pour le chlortoluron, le carbofurane et le bentazone). Dans nos conditions expérimentales optimales (I = 300 mA, [pesticide]0 = 0,125 mM et t = 8 h), nous obtenons un taux de minéralisation supérieur à 90% pour les trois pesticides. Dans le cas des molécules étudiées, il a été montré que le taux de minéralisation par le procédé photo-Fenton (UV/Fe3+/H2O2) est fonction des doses des réactifs utilisés et de la concentration initiale des pesticides à traiter. Une comparaison des performances de minéralisation par les différents procédés étudiés (électro-Fenton (BDD), électro-Fenton (PT), oxydation anodique et photo-Fenton) a montré que les procédés photo-Fenton et électro-Fenton (BDD) permettent d’atteindre des taux de minéralisation très importants (˜ 90% au bout de 2 h). La comparaison du coût du traitement montre que le procédé photo-Fenton coûte beaucoup plus chère que le procédé électro-Fenton (BDD). Le plasma d’air humide a été utilisé pour la dégradation du chlortoluron. Différents catalyseurs (Fe2+, Fe3+ et TiO2) ont été étudiés pour améliorer les performances du glidarc. La combinaison entre TiO2 et Fe2+ permet d’aboutir à 96% de la dégradation du chlortoluron au bout de 3h / The use of advanced oxidation electrochemical process: Electro-Fenton is an easy and economical way to obtain hydroxyl radical (•OH) strongly oxidizing. During this work radicals were used for the degradation of chlortoluron, carbofuran and bentazon in aqueous medium. The methodology of experimental research has been used to study the influence of some parameters (initial concentration, current intensity and processing time) on the rate of degradation and to determine the optimum conditions for mineralization. The evolution of chlortoluron concentration with processing time shows a pseudo first order kinetics ( (4.92 × 109, 109 × 3.24 × 2.63 and 109 M-1 S-1 respectively for the chlortoluron, and Carbofuran bentazon). In our optimal conditions (pH = 3, I = 300 mA, [pesticide]0 = 0.125 mM and t = 8 h), we obtain a TOC removal ratio more than 90% for the three pesticides. In the case of molecules studied, it was shown that the rate of mineralization by the photo-Fenton (UV/Fe3+/H2O2) is a function of doses of reagents used and the initial concentration of pesticides treaty. A comparison of the performance of mineralization by the different processes studied (Electro-Fenton (BDD), Electro-Fenton (PT), anodic oxidation and photo-Fenton) has shown that more than 90% of TOC removal was obtained after only 2 hours of photo-Fenton and electro-Fenton (BDD) process. Nevertheless, a comparison of the cost treatment shows that photo-Fenton process is more expensive than electro-Fenton (BDD). The plasma humid air was used for chlortoluron degradation. Different catalysers (Fe2+, Fe3+ and TiO2) were studied to improve the glidarc performances. The combination of TiO2 and Fe2+ can reach 96% of chlortoluron degradation after 3h
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LEDs-UV como fontes luminosas alternativas para processos oxidativos avançados: inativação de nitrofurantoína pelo processo foto-Fenton / UV LEDs as alternative light sources for Advanced Oxidation Process: Inactivation of Nitrofurantoin by the photo-Fenton processLabriola, Vanessa Feltrin 10 April 2017 (has links)
O objetivo desta pesquisa foi estudar a degradação,pelo processo foto-Fenton, de um poluente-modelo (um antibiótico da classe dos nitrufuranos:a nitrofurantoína), utilizando-seLEDs-UV no lugar das lâmpadas tradicionalmente utilizadas, ou seja, das lâmpadas fluorescentes negras.Foram comparadas duas câmaras de irradiação, cada uma com um tipo de fonte, em termos de: porcentagem de remoção, ecotoxicidade (Lactuca sativa), atividade antimicrobiana (Escherichia coli), custos de capital (equipamentos), de operação (consumo energético) e das fontes luminosas, além do espaço ocupado. Os experimentos de degradação foramrealizados e otimizados via planejamento experimental, utilizando-se a Metodologia de Superfície de Resposta, obtendo-se as concentrações ótimas denitrofurantoína, de íons férricoe de peróxido de nitrogênio para cada caso.As câmaras estudadas apresentaram desempenhos semelhantes na remoção de nitrofurantoína (mais de 95% em 15 min), além de não ter havido a geração de produtos ecotóxicos (Lactuca sativa) e de ter sido alcançada a inativação biológica (Escherichia coli) do fármaco.A câmara de irradiação com LEDs é compacta, custa duas vezes menos que a outra e é quatro vezes mais eficiente em termos de consumo elétrico. A única desvantagem encontrada foi o custo dos LEDs-UV. Levando-se em conta o número de LEDs e de lâmpadas fluorescentes negras nas câmaras, o custo é trinta vezes maior. No entanto, o custo adicional dos LEDs-UV em relação às lâmpadas fluorescentes negras é facilmente compensado pela economia realizada nos custos de capital (aquisição do equipamento) e de operação (consumo energético).Em suma, pelo menos no caso da degradação da nitrofurantoína pelo processo foto-Fenton, os LEDs-UV mostraram-se substitutos vantajosos das lâmpadas fluorescentes negras, tradicionalmente utilizadas. / The goal of this research was to study the degradation, by the photo-Fenton process, of a model-pollutant (an antibiotic fromthe nitrofurans group: nitrofurantoin), using UV-LEDs instead of the lamps traditionally used, i.e. black fluorescent lamps. Two irradiation chambers were compared, each one of them with a type of light source, regarding: removal percentage, ecotoxicity (Lactuca sativa), antimicrobial activity (Escherichia coli), capital costs (equipment), operating costs (energy consumption), and light sources costs, as well as the space the chambers occupy.The degradation experiments were performed and optimized by experimental design, using the Response Surface Methodology, and obtaining the optimum concentrations of nitrofurantoin, ferric ions, and hydrogen peroxide, for each of the chambers. The studied chambers showed similar performances regarding nitrofurantoin removal (more than 95% in 15 min), besides the generation of no ecotoxic products (Lactuca sativa) and the biological inactivation (Escherichia coli) of the drug. The irradiation chamber with UV-LEDs is compact,cheaper (it is half of the price of the other one), and it is four times more efficient in terms of electric consumption. The sole disadvantage found was the cost of the UV-LEDs. Taking into consideration the number of LEDs and black fluorescent lamps used in the chambers, thiscost is 30 times greater. However, the additional cost of the UV-LEDsin comparison to black fluorescent lamps is easily compensated by the savings in capital costs (equipment acquisition) and operating costs (electric consumption). In summary, at least regarding the nitrofurantoin degradation by the photo-Fenton process, the UV-LEDs proved to beworthwhile alternatives for black fluorescent lamps, which are traditionally used.
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Degradação de metilparabeno e propilparabeno pelo processo foto-Fenton solar / Methylparaben and propylparaben degradation by solar photo-Fenton processAraujo, Rodrigo Rossi de 23 February 2018 (has links)
Neste trabalho, utilizou-se um Processo Oxidativo Avançado (POA) para a degradação de uma solução aquosa contendo uma mistura de metilparabeno e propilparabeno (50 μg L-1 cada). O processo estudado foi o foto-Fenton solar, em um reator do tipo CPC operado no modo batelada com reciclo total. As condições operacionais foram otimizadas por meio da Metodologia de Superfície de Resposta (MSR), sendo elas: 771,6 μg H2O2 L-1, 65,3 μg Fe3+ L-1 e vazão 0,9 L min-1. O pH foi fixado em 2,5. A determinação das concentrações dos analitos foi realizada por Cromatografia Líquida de Alta Eficiência acoplada a um Detector de Arranjo de Diodos (CLAE-DAD), tendo sido monitorado o comprimento de onda 258 nm. Utilizou-se como técnica extratora e de pré-concentração a Microextração Líquido-Líquido Dispersiva (MELLD), sendo o n-octanol o solvente extrator e a acetona o solvente dispersivo. Avaliou-se a cinética de degradação do processo otimizado (em triplicata), obtendo-se uma degradação > 99% em 50 min. As constantes de taxa (em função da dose de energia, unidades m² kW-1) foram 1,2 ± 0,034 (R² = 0,987) e 1,1 ± 0,042 (R² = 0,979) para o metilparabeno e o propilparabeno, respectivamente. O efluente do reator mostrou-se biologicamente inativo, tendo sido testadas sua ecotoxicidade (Lactuca sativa) e sua atividade antimicrobiana (Escherichia coli). / In this work, an Advanced Oxidation Process (AOP) was used for the degradation of aqueous methylparaben and propylparaben (50 μg L-1 each). The studied process was the solar photo-Fenton reaction, using a CPC-type reactor, which was operated in batch mode with total recycle. The experimental conditions were optimized using the Response Surface Methodology (RSM) and the obtained results were: 771.6 μg H2O2 L-1, 65.3 μg Fe3+ L-1, and flow rate 0,9 L min-1. The solution pH was set at 2.5. The analytes concentration were determined by High Efficiency Liquid Chromatography coupled to a Diode-Array Detector (HPLC-DAD), monitoring the 258 nm wavelength. The Dispersive Liquid-Liquid Extraction was used as a pre-concentration and extraction technique before injection, whereas n-octanol was the extraction solvent and acetone was the dispersive one. The optimized degradation process kinetics was assessed (triplicate) and more than 99% degradation was obtained after 50 min. The rate constants (normalized by the energy dose, m2 kW-1 units) were 1.2 ± 0.034 (Rsup>2 = 0.987) and 1.1 ± 0.042 (R2 = 0.979) for methylparaben and propylparaben, respectively. The reactor effluent was biologically inactive, regarding its ecotoxicity (Lactuca sativa) and antimicrobial activity (Escherichia coli).
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Acoplamento entre processos biológicos e oxidativos avançados para o tratamento de esgoto sanitário: degradação de fármacos e reúso seguro / Coupling between biological and advanced oxidative processes for treating sanitary wastewater: pharmaceuticals degradation and safe reuseSilva, Thiago Henrique Gomes da 12 May 2017 (has links)
É consenso entre os cientistas que as Estações de Tratamento de Esgoto são as principais formas de entrada de fármacos no ambiente aquático. Isso acontece porque os processos biológicos convencionais utilizados para o tratamento do esgoto sanitário não são eficientes quanto à remoção de muitos desses compostos sintéticos. Neste contexto, o pós-tratamento utilizando um Processo Oxidativo Avançado (POA) pode degradar os compostos pouco biodegradáveis e produzir água para reúso seguro. Portanto, esta Tese estuda o acoplamento entre um processo biológico anaeróbio-aeróbio e compara dois POA, foto-Fenton e Fenton heterogêneo, como alternativas de pós-tratamento. Os experimentos foram feitos utilizando-se esgoto sanitário real como matriz. Sendo assim, na primeira etapa deste trabalho, um método SPE-HPLC-MS/MS foi desenvolvido e validado para a quantificação dos fármacos Ranitidina, Diclofenaco e Sinvastatina naquela matriz complexa. Na segunda etapa, a degradação dos fármacos por processos biológicos foi estudada em reatores operados em batelada e de escoamento contínuo. Desenvolveu-se uma metodologia para a identificação dos produtos de biodegradação e encontrou-se que tais metabólitos são recalcitrantes e possuem potencial poluidor. Observou-se que os fármacos e seus metabólitos causam efeito tóxico crônico sobre a biomassa, pois a produção de metano foi prejudicada quando comparada à da biomassa que não foi exposta a esses compostos. Na terceira etapa, os POA foram estudados em batelada para se determinar as melhores condições de operação que seriam testadas nas etapas seguintes. Encontrou-se, para o processo foto-Fenton, que os fármacos foram completamente degradados quando se utilizavam duas lâmpadas (16 W de potência elétrica total), ferro (III) e peróxido de hidrogênio nas concentrações de 3,0 e 40 mg L−1, respectivamente, e tempo de detenção hidráulica de 10 min. Zeólita natural foi utilizada como suporte na síntese de um catalisador para Fenton heterogêneo. O catalisador foi estável em condições críticas de reação, porém não pôde degradar os compostos cujas dimensões moleculares eram maiores do que os seus poros. Os processos foram acoplados e operados em modo contínuo durante dez dias, período no qual permaneceram estáveis. Os custos foram estimados e verificou-se que, embora o processo Fenton heterogêneo necessite de 1/3 do capital comparado ao foto-Fenton, o processo heterogêneo não é interessante porque o custo operacional é 4 vezes maior e o processo é limitado para a degradação de moléculas pequenas. Já o processo foto-Fenton degradou todos os fármacos e metabólitos com remoção de carbono orgânico dissolvido e produzindo água potencialmente segura para seu reúso ao custo operacional de US$ 0,27 m−3. Portanto, o processo foto-Fenton foi a melhor alternativa de pós-tratamento avaliada nesta Tese. O processo Fenton heterogêneo seria atrativo apenas para a degradação de moléculas pequenas. / Scientists generally agree that Sewage Treatment Plants are the main inputs of pharmaceuticals into the aquatic environment. That happens because the conventional biological processes used for treating sewage are not efficient in removing many of those synthetic compounds. In this context, Advanced Oxidation Processes (AOP), used as post-treatments, can degrade the poorly biodegradable compounds and produce water for safe reuse. Therefore, this Thesis studies the coupling between an anaerobic-aerobic biological process and compares two AOP, photo-Fenton and heterogeneous Fenton, as post-treatment alternatives. The experiments were performed using real sewage as a matrix. Thus, in the first step of this work, an SPE-HPLC-MS/MS method was developed and validated for the quantification of the pharmaceuticals Ranitidine, Diclofenac, and Simvastatin in that complex matrix. In the second step, the pharmaceuticals degradation by biological processes was studied in batch and continuous flow reactors. A methodology was developed for identifying the biodegradation products and these metabolites were found to be recalcitrant and to have polluting potential. It was observed that the pharmaceuticals and their metabolites caused a chronic toxic effect on biomass, as methane production was impaired when compared to the biomass not exposed to these compounds. In the third step, the AOP were studied in batch mode to determine the best operating conditions that would be tested in the following steps. In the photo-Fenton process, the pharmaceuticals were completely degraded when two lamps (16 W total electric power), iron (III), and hydrogen peroxide were used in the concentrations of 3.0 and 40 mg L−1, respectively, with hydraulic detention time of 10 min. Natural zeolite was used as a support for the synthesized catalyst for heterogeneous Fenton. The catalyst was stable under critical reaction conditions, but it was not able to degrade compounds whose molecular dimensions were larger than its pores. The processes were coupled and operated in continuous mode for ten days, during which they remained stable. Considering the involved estimated costs, although the heterogeneous Fenton process requires 1/3 of the capital costs when compared to the photo-Fenton process, the heterogeneous one is not interesting because its operating cost is 4 times higher and it is limited to the degradation of small molecules. On the other hand, the photo-Fenton process degraded all pharmaceuticals and their metabolites, removed dissolved organic carbon, and produced water potentially safe for reuse at the operational cost of US$ 0.27 m−3. Therefore, the photo-Fenton process was the best post-treatment alternative assessed in this Thesis. The heterogeneous Fenton process would be suited only for the degradation of small molecules.
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