Dissertations / Theses on the topic 'Electro-Fenton process'

Ce manuscrit de thèse est consacré à la modification de feutres de carbone pour la préparation de matériaux d’électrodes hautement performants pour le procédé électro-Fenton (EF), appliqué aux traitements des eaux chargées en polluants bioréfractaires. Dans un premier temps, des feutres de carbone commerciaux (CF) ont été mis en œuvre pour optimiser l'élimination de colorants (Acide Orange) et de produits pharmaceutiques (Paracétamol). Les chemins réactionnels conduisant à la minéralisation de ces polluants bioréfractaires ont été élucidés et la toxicité des sous-produits identifiés a été déterminée à différents temps d’électrolyse. Dans la suite du travail, une nouvelle cathode a été préparée par dépôt électrochimique d'oxyde de graphène réduit (rGO) sur la surface des feutres de carbone commerciaux. Divers moyens de réduction ont été étudiés et les propriétés structurales et texturales de l'électrode modifiée ont été déterminées par microscope électronique à balayage, diffraction des rayons X, Spectrométrie photoélectronique X, BET et mesure d'angle de contact. La cathode élaborée présente une bonne stabilité et une grande efficacité de traitement lorsqu'elle est appliquée pour décomposer l’Acide Orange 7 (AO7), la molécule de colorant azoïque modèle choisie. Dans une dernière partie du travail, nous avons proposé un système original de traitement électrochimique de type EF à base d’une pile à glucose. Dans ce système, l’énergie nécessaire est fournie par l’oxydation du glucose à l’anode, sur feutre de carbone décoré de nanoparticules d’or alors que la cathode est constituée du feutre modifié par un carbone microporeux dopé en azote présentant des propriétés d’électrocatalyse compatibles à la réduction de l’oxygène en peroxyde d’hydrogène dans la cellule de type pile à combustible. Le manuscrit présente la synthèse et la caractérisation de ces deux électrodes. L’originalité du travail réside en la quantité particulièrement faible d’or nécessaire à l’anode et au potentiel de réduction de l’oxygène particulièrement haut obtenus sur les carbones microporeux dopés à l’azote. Les propriétés catalytiques de l'anode et de la cathode ont induit une densité de courant de sortie stable (360,3 ± 51,5 mA.m-2 à 400 ± 50 mV) et maintenue à long terme. En conséquence, 90% de la concentration initiale du polluant (AO7) a été éliminée après une dégradation prolongée de 10 h. La puissance de la cellule est faible (170 mW.m-2) mais constante au moins pendant deux mois. Cette première preuve de concept d'un système abiotique de type pile à combustible - Fenton a démontré une efficacité élevée vis-à-vis de la dégradation des polluants bioréfractaires avec un énorme potentiel dans les domaines liés à l'énergie et la protection de l’environnement
This thesis manuscript presented the modification and application of carbon felt material for wastewater treatment accommodating biorefractory pollutants by electro-Fenton (EF) process. First of all, the optimal condition of EF treatment for dye/pharmaceuticals removal using commercial carbon felt (CF) was investigated. From that, the degradation pathways in the relationship with the toxicity of their by-products were built and proposed. Concerning the modification for commercial CF, a new cathode was set up by electrochemical deposition of reduced Graphene Oxide (rGO) on the surface of CF via various reduction ways. The structure property of modified electrode was investigated by SEM, XRD, XPS, BET and contact angle measurement. The new cathode exhibited good stability and high treatment efficiency when it was applied to decompose Acid Orange 7 (AO7), a model azo dye molecule. The EF treatment was also developed further by contributing a new Fuel-cell Fenton system without any external power supply. In this approach, AO7 was continuously chosen to degrade by electro-Fenton process at a designed cathode (Carbon Felt (CF)/porous Carbon (pC)) supplied by direct clean electrical energy from abiotic glucose oxidation at a CF/gold anode (CF@Au). The catalytic properties of both anode and cathode induced a stable output current density of 360.3 ± 51.5 mA m−2 at 400 ± 50 mV, maintained for long-term period. As a consequence, 90 % of the initial concentration of the pollutant, identified by HPLC analysis, was eliminated upon extended EF degradation for 10 h, and the cell power output of 170 mW m-2 was stable at least for two months. Hence, this first proof of concept of an abiotic Fuel cell – Fenton system demonstrated a high efficiency towards pollutant degradation with a huge potential in both energy-related areas and environmental protection

La pollution des ressources en eau est un des défis importants auquel les Hommes doivent faire face. En particulier, de nouvelles solutions doivent émerger, puisque les techniques conventionnelles de traitement utilisées actuellement ne permettent pas une élimination efficace des divers polluants. Parmi les polluants émergents, les composés pharmaceutiques ont récemment été détectés dans différentes sources d'eau à travers le monde. Leurs effets indésirables sur l'environnement naturel et sur l'Homme ont déjà été reconnus mais doivent encore être éclaircis. De nombreux nouveaux procédés de traitement de l'eau apparaissent. En particulier, le procédé électro-Fenton a démontré sa capacité à éliminer les pharmaceutiques et autres contaminants persistants. Ce procédé est basé sur la génération in-situ d'une espèce oxydante très puissante, les radicaux hydroxyles (OH), qui permettent la dégradation non-sélective des polluants. Cependant, cela nécessite l'utilisation d'une quantité d'énergie importante, relativement coûteuse. Une solution viable est de coupler le procédé électro-Fenton avec un procédé biologique. En effet, l'utilisation de ce dernier est beaucoup plus économique, mais il possède une efficacité limitée envers les polluants persistants tels que les pharmaceutiques. Ainsi, le procédé hybride bio-électro-Fenton apparaît comme un bon compromis entre le coût et l'efficacité. Le but de cette thèse de doctorat a donc été d'optimiser le procédé électro-Fenton dans l'optique de le coupler avec un procédé biologique, afin d'éliminer les pharmaceutiques. Les principaux objectifs de cette étude reposent sur l'étude de l'influence des paramètres opératoires utilisés au cours du procédé électro-Fenton sur (a) la dégradation des pharmaceutiques ; (b) la minéralisation de la matière organique ; (c) l'évolution de la biodégradabilité; (d) la consommation énergétique. Cette thèse est composée de trois parties, au cours desquelles la complexité des solutions traitées a progressivement augmentée. Premièrement, une étude a été menée sur des solutions de produits pharmaceutiques seuls afin de mieux comprendre les mécanismes impliqués au cours de leur dégradation. La seconde partie porte sur l'étude expérimentale d'une solution synthétique composée d'un mélange de 13 pharmaceutiques. La dernière étape a consisté à mettre en place un procédé bio-électro-Fenton pour le traitement d'un effluent pharmaceutique réel. Cette démarche progressive a permis de mieux comprendre l'influence des paramètres opératoires utilisés au cours du procédé électro-Fenton. Les principaux résultats obtenus sont notamment l'optimisation de deux paramètres opératoires important : la concentration du catalyseur (Fe2+) et l'intensité du courant. L'influence de ces paramètres s'est révélée similaires au cours du traitement de tous les types de solution testée. Il a donc été possible de conclure que les valeurs optimales sont une concentration en Fe2+ de 0,2 mM et une intensité entre 100 et 500 mA. L'efficacité d'élimination des pharmaceutiques a été plus importante en utilisant des intensités plus faibles (100-300 mA). Cependant, la biodégradabilité de l'effluent, un paramètre important dans l'optique du post-traitement biologique, a été d'avantage augmentée en utilisant des intensités élevées (500-1000 mA). Par ailleurs, l'utilisation d'intensités élevées a aussi mené à augmenter la consommation énergétique, en particulier dans le cas de temps de traitement longs. Il apparaît donc évident qu'un compromis entre efficacité et consommation énergétique doit être trouvé pour chaque cas particulier et effluent à traiter. Pour conclure, les avancées de cette recherche sont principalement attribuées à la nouveauté de la combinaison bio-électro-Fenton. L'étude de l'influence des paramètres opératoires du procédé électro-Fenton a aussi permis d'améliorer la compréhension de cette nouvelle technique et contribue à son développement vers une application industrielle
Water pollution is one of the biggest challenges that humanity faces and combating it requires the development of treatment processes, as conventional methods used nowadays are no longer effective for the removal of various complex pollutants. Recently pharmaceuticals have been recognized to be contaminants of emerging environmental concern as their traces were detected in a spectrum of water bodies around the globe. The long term effects of their presence in a natural environment are not yet fully studied, but the potential outcomes can be detrimental to a sustainable future. Among the variety of currently rising treatment technologies, the electro-Fenton method, an electrochemical advanced oxidation process, has demonstrated an ability to eliminate pharmaceuticals as well as other types of persistent contaminants. This electrocatalytical process generates in situ strong oxidants species - hydroxyl radical (OH) - which non-selectively degrade organic pollutants. Due to the extensive cost in the application of electrical energy, its operation might be cost-prohibitive. A solution would be to combine it with biological processes which are more economically viable, but also less effective in the removal of pharmaceuticals. The combined process is expected to have a synergetic effect between cost and effectiveness. The goal of this PhD thesis is to optimize operating conditions of the electro-Fenton process for a feasible combination with a biological process as a means of treating pharmaceutical pollution. The main objectives addressed by this work are related to the influence of operating parameters of the electro-Fenton process on (a) removal of pharmaceuticals; (b) mineralization of organic matter; (c) enhancement of biodegradability; (d) energy consumption. The thesis has three distinct parts related to the type of treated aqueous solution. First, a mechanistic study was conducted on aqueous solutions of individual pharmaceuticals in order to understand general trends of their removal. Next, a series of experiments was carried out on a synthetic mixture of thirteen pharmaceuticals from different therapeutic classes. Lastly, laboratory bench-scale reactors of a combined bio-electro-Fenton process were operated for the treatment of real wastewater. The advance in the complexity of the treated solution allowed a comprehensive comparison and analysis of the influence of the operating parameters. The main results include the optimal values of two operating parameters: the catalyst (Fe2+) concentration and the applied current intensity for a given electro-Fenton setup. The effects of the operating parameters on the removal of pharmaceuticals and other organic matter were similar regardless of the treated solution. The optimal value for the Fe2+ concentration was concluded to be around 0.2 mM. The optimal current intensity was in the range 100-500 mA. The efficiency of the current in terms of the pharmaceuticals' removal was the highest with the lowest intensity (100-300 mA). At the same time the biodegradability, which was an important factor in the biological post-treatment process, improved with higher intensities of electric current (500-1000 mA). However, high current intensities resulted in an elevated energy consumption, particularly with a prolonged treatment time. A tradeoff would have to be consequently made between energy saving and the removal rates that should be found in any single case. The novelty of the research presented in this PhD thesis is firstly attributed to the novelty of the combination of electro-Fenton to a biological process. A detailed study of the influence of operating parameters of the electro-Fenton process on removal rates and biodegradability enhancement contributed not only to the general knowledge on the electro-Fenton process, but also to the advancement towards its upscaling and then further towards the industrial application of this technique

Les procédés électrochimiques d'oxydation avancée constituent une technologie efficace pour traiter les produits pharmaceutiques car ils permettent la formation d'oxydants puissants tels que les radicaux hydroxyles capables d'éliminer presque tout type de contaminants organiques grâce à leur très haut pouvoir oxydant. Parmi eux, l’électro-Fenton et l’oxydation anodique sont des méthodes respectueuses de l'environnement car ils n'utilisent aucun réactif chimique (oxydation anodique) ou uniquement l'oxygène de l'air et des ions fer en tant que catalyseur (électro-Fenton).Dans cette thèse, quatre produits pharmaceutiques appartenant à des familles différentes ont été sélectionnés en fonction de leur toxicité et de leur présence dans les eaux de l'environnement. Leur élimination de l'eau a été effectuée par électro-Fenton. Les objectifs de ce travail étaient de déterminer (i) les meilleures conditions opératoires à l’échelle du laboratoire (courant et concentration du catalyseur), (ii) la cinétique de dégradation et de minéralisation et enfin (iii) de proposer une voie de minéralisation basée sur des intermédiaires aromatiques, des acides carboxyliques et des ions libérés dans la solution.Comme ces traitements ont été appliqués avec succès, un réacteur pilote composé alternativement d'anodes en BDD et de cathodes en feutre de carbone, doté d’un système d'aération et fonctionnant en mode continu a été construit pour évaluer la faisabilité d’un changement d’échelle et se diriger vers une pré-industrialisation du procédé. Différentes configurations d'électrodes ont été testées. Le débit et le courant se sont avérés être plus influents sur le taux de minéralisation et sur la consommation d'énergie, respectivement. Pour mieux comprendre le rôle du débit et des configurations, une étude hydrodynamique a été réalisée. Le modèle hydrodynamique a été associé à un modèle cinétique de minéralisation afin d'obtenir un modèle permettant de prédire le pourcentage de minéralisation à différentes positions à l'intérieur du réacteur en régime permanent. Ainsi, ce modèle peut aider à optimiser les conditions opératoires et à dimensionner les futurs réacteurs en fonction de l’objectif de minéralisation du traitement (taux de minéralisation élevé, traitement combiné, flux élevé,…).Afin de réduire les coûts opératoires, la combinaison d’un procédé électrochimique et d’un traitement biologique a ensuite été étudiée. Afin d’obtenir un traitement combiné efficace, il a été constaté que le traitement électrochimique devait (i) dégrader l'hydrochlorothiazide (ii) réduire de manière significative la concentration de ses intermédiaires aromatiques car ils inhibent de manière significative l'activité bactérienne, (iii) favoriser la formation de molécules biodégradables telles que les acides carboxyliques. La biodégradation de quatre acides carboxyliques formés lors du traitement par électro-Fenton de l'hydrochlorothiazide a également été étudiée. Il a été démontré qu'ils étaient dégradés de manière séquentielle avec différentes phases de latence et cinétiques de dégradation. Ainsi, pour les minéraliser, un réacteur de type «piston» est recommandé. La combinaison de traitement a ensuite été appliquée à un traitement électrochimique effectué à faible courant avec une anode en BDD et une anode en Platine. Un degré de minéralisation de 38 et 50% a été obtenu par le traitement biologique permettant d'atteindre un taux de minéralisation global de 66 et 85% avec les anodes en BDD et Platine respectivement. Ainsi, cette combinaison de traitement a été un succès, un changement d’échelle du procédé peut alors être envisagé
Electrochemical advanced oxidation processes (EAOPs) constitute an efficient technology to treat the pharmaceuticals as they allow the formation of strong oxidants such as hydroxyl radicals able to remove nearly any type of organic contaminants thanks to their very high oxidation power. Among them the electro-Fenton and anodic oxidation processes are environmentally friendly methods as they use no chemical reagent (anodic oxidation) or only oxygen of air and iron ions as a catalyst (electro-Fenton).In this thesis, four pharmaceuticals from different families and structures were selected based on their toxicity and their occurrence in environmental waters and their removal from water was performed by EAOPs. The objectives of this work were to determine the best operating conditions at lab scale (current and catalyst concentration), investigate the kinetic of degradation and mineralization and finally propose a mineralization pathway based on aromatic intermediates, carboxylic acids and ions released to the solution.As these treatments were successfully applied, a lab scale pilot reactor composed alternately of BDD anodes and carbon felt cathodes with a bottom aeration system and working in the continuous mode was built to scale-up these processes in order to pre-industrialize them. Different configurations of electrodes were tested. The flow rate and the current were found to be more influent on the mineralization rate and on the energy consumption, respectively. To deeper understand the role of the flow rate and the configurations a hydrodynamic study was performed. The hydrodynamic results were gathered with a kinetic model for the mineralization to obtain a model predicting the percentage of mineralization at different position inside the reactor during the steady state. Thus, this model can help to optimize the operating conditions and to size future reactors depending on the mineralization objective of the treatment (high mineralization rate, combined treatment, high flow, …).To reduce operating cost, the combination of an electrochemical process and a biological treatment was then investigated. In this frame, it was found that electrochemical treatment can (i) degrade the hydrochlorothiazide (ii) reduce significantly the concentration of its aromatic intermediates as they were shown to significantly inhibit the bacterial activity, (iii) promote the formation of biodegradable molecules such as carboxylic acids. The biodegradation of four carboxylic acids formed during the electro-Fenton treatment of the hydrochlorothiazide at lab scale was also studied. It was demonstrated that they were sequentially degraded with different lag phases and kinetics of degradation. Thus to mineralize them, a “plug flow” type reactor is recommended. The combination of treatment was then applied with an electrochemical treatment performed at low current with a BDD anode and a Platine anode. A mineralization degree of 38% and 50% were obtained by the biological treatment enabling to globally reach a mineralization rate of 66% and 85% with the BDD and the Platine anodes respectively. Thus this combined treatment was successful and open the way for the scale-up of these processes

Esta tesis doctoral versa sobre el tratamiento de aguas contaminadas con fármacos sulfamidas como el ácido sulfanílico (SA), la sulfanilamida (SNM) y la sulfametazina (SMZ). Estos compuestos se han degradado en una disolución sintética ácida mediante diversos procesos electroquímicos de oxidación avanzada (EAOPs) tales como la oxidación anódica (AO) en celda dividida y no dividida y los procesos electro-Fenton (EF), fotoelectro-Fenton UVA (PEF) y fotoelectro-Fenton solar (SPEF). En AO se ha usado un ánodo de diamante dopado con boro (BDD) y un cátodo de acero inoxidable en celdas de 100 mL, mientras que en EF, PEF y SPEF se ha utilizado un ánodo de BDD o de Pt y un cátodo de difusión de aire (ADE) o de fieltro de carbón en una celda de 100 o 230 mL. Se ensayó el efecto de variables experimentales como la intensidad de corriente, la concentración del fármaco y del catalizador de Fe2+ y el pH sobre la cinética de mineralización del SA, SNM y SMZ. Los procesos de AO en celda dividida y de PEF operando entre 50 y 450 mA conducían a una mineralización total con una reducción del carbono orgánico total (TOC) superior al 98%. El aumento de la intensidad siempre daba lugar a una mayor velocidad de mineralización debido a la mayor producción de radicales hidroxilo (●OH) vía oxidación del agua en AO, junto a la acción sinérgica del ●OH formado por la reacción de Fenton y de la luz UVA en PEF. También se consiguió una mineralización total para disoluciones concentradas hasta 2530 mg L-1 de SA, 2390 mg L-1 de SNM y 1930 mg L-1 de SMZ, tardando más tiempo aquellas con mayor contenido de sustrato. La cinética de desaparición del sustrato siempre obedecía una reacción de pseudo-primer orden. Se siguió la evolución con el tiempo de electrólisis de la hidroquinona, la p-benzoquinona y los ácidos oxálico y oxámico para el SA, y del catecol, resorcinol, hidroquinona, p-benzoquinona, 1,2,4- trihidroxibenceno y los àcidos maleico, fumárico, acético, oxálico, fórmico y oxámico para la SNM mediante HPLC. Para la SMZ, se detectaron la 4,6-dimetil-2-pirimidinamina, el catecol, el resorcinol, la hidroquinona y la p-benzoquinona por GCMS, y los ácidos maleico, fumárico, acético, fórmico, oxálico y oxámico por HPLC. Se confirmó que el N inicial se convertía principalmente en ion NH4 + y en mucha menor proporción en ion NO3-. A partir de estos resultados, se ha propuesto un camino de reacción plausible para la mineralización de cada compuesto por los EAOPs ensayados. Además, se evaluó la toxicidad de la disolución a partir de la inhibición de la luminiscencia de las bacterias Vibrio fischeri en EF. La toxicidad adquirió su valor máximo a cortos tiempos de electrólisis cuando se producían los productos aromáticos más tóxicos, pero la disolución se desintoxicó totalmente al final del tratamiento, independientemente del ánodo utilizado. En vista de los excelentes resultados encontrados para el PEF, el estudio de la degradación del SA se amplió a una planta pre-piloto solar de 2,5 L como un primer paso de la aplicación del proceso de SPEF a nivel industrial. El reactor era de Pt/ADE y se probó comparativamente el tratamiento de EF para clarificar la acción sinérgica de la luz solar. Ambos procesos se optimizaron mediante la aplicación de un diseño central compuesto acoplado con metodología de superficie de respuesta. Se obtuvo que las variables óptimas eran 100 mA cm-2, 0,5 mM de Fe2+ y pH 4,0. Se encontraron resultados similares para la SNM usando la misma planta pre-piloto. El proceso de SPEF permitió una mineralización del 94%, de forma más rápida a medida que la densidad de corriente aumentaba de 50 a 150 mA cm-2, mientras que las degradaciones comparables por EF dieron menor descontaminación.
This doctoral thesis is devoted to the degradation of sulfanilic acid (SA) and sulfa drugs as sulfanilamide (SNM) and sulfamethazine (SMZ) in acidic aqueous medium using electrochemical advanced oxidation processes (EAOPs) like anodic oxidation (AO) in divided and undivided cells and electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar photoelectro-Fenton (SPEF). AO experiments were made in 100 mL cells with a boron-doped diamond (BDD) anode and a stainless steel cathode, whereas in EF, PEF and SPEF, the cell of 100 or 230 mL was equipped with a BDD or Pt anode and an airdiffusion (ADE) or carbon-felt cathode. The AO process in divided cell and PEF between 50 and 450 mA gave total mineralization with > 98% total organic carbon reduction. Increasing current always accelerated the mineralization due to the higher production of ●OH via wáter oxidation in AO, along with ●OH formed from Fenton’s reaction and UVA action in PEF. Total mineralization was achieved up to 2530 mg L-1 SA, 2390 mg L-1 SNM and 1930 mg L-1 SMZ. The substrate decay always obeyed a pseudo-first-order kinetics. HPLC allowed detecting intermediates like hydroquinone, p-benzoquinone and oxalic and oxamic acids for SA, and catechol, resorcinol, hydroquinone, p-benzoquinone, 1,2,4-trihydroxybenzene and fumaric, maleic, acetic, oxalic and formic acids for SNM. In the case of SMZ, 4,6-dimethyl-2-pyrimidinamine and catechol, resorcinol, hydroquinone and p-benzoquinone were detected by GC-MS and mainly oxalic and oxamic acids by HPLC. The initial N was lost mainly as NH4+ ion and, in lesser proportion, as NO3- ion. These results allowed the proposal of a reaction sequence for each compound by the EAOPs tested. The study of SA degradation was further extended to a solar pre-pilot plant of 2.5 L with a Pt/ADE reactor as a first step of the application of SPEF to industrial level. The EF and SPEF processes were optimized by means of response surface methodology, yielding 100 mA cm-2, 0.5 mM Fe2+ and pH 4.0 as best variables. Similar results were found for SNM using the same pre-pilot plant. The SPEF process allowed 94% mineralization, more rapidly when current density rose from 50 and 150 mA cm-2, while the comparative EF process yielded lower decontamination.

La présence des antibiotiques à usage humain et vétérinaire dans l’écosystème aquatique, est devenue un problème écologique sérieux. En effet, ces substances résistent aux traitements des stations d’épuration, ce qui engendre leur introduction et accumulation dans l’environnement. Par conséquent, le développement de méthodes efficaces pour le traitement de ces polluants est nécessaire. La première partie de ce travail de thèse s’inscrit dans le cadre de la dégradation des antibiotiques par procédé électro-Fenton. Ce procédé consiste à produire in situ des espèces fortement oxydantes, les radicaux hydroxyle, permettant la dégradation totale des composés organiques persistants. La sulfaméthazine (SMT) et le triméthoprime (TMP) ont été choisis comme composés modèles, en raison de leur détection régulière dans les effluents des stations d’épuration, les eaux de surface et les eaux souterraines. Dans cette première partie, nous avons examiné l’influence de différents paramètres expérimentaux, sur l’efficacité du procédé électro-Fenton. Les conditions opératoires optimales nécessaires pour la dégradation totale des deux antibiotiques étudiés, ont été également déterminées. En outre, les produits intermédiaires aromatiques générés lors de la dégradation des deux antibiotiques, ont été identifiés. Leur évolution durant l’électrolyse a été également suivie. La deuxième partie est consacrée à l’étude de la minéralisation de la SMT et du TMP par procédé électro-Fenton. Les résultats obtenus indiquent que les taux de minéralisation de la SMT et du TMP sont respectivement de 91 et 85% après dix-huit heures de traitement. Les acides carboxyliques formés, ainsi que les ions inorganiques libérés ont été identifiés, leur évolution a été suivie au cours du traitement. De plus, en se basant sur les différents sous-produits générés, nous avons proposé des mécanismes réactionnels pour la minéralisation de la SMT et du TMP par procédé électro-Fenton. La troisième partie de ce travail porte sur l’étude de la minéralisation des deux antibiotiques considérés par couplage du procédé électro-Fenton et d’un traitement biologique. La SMT et le TMP, ont été prétraités par procédé électro-Fenton, ce qui a conduit à leur dégradation totale, avec des taux de minéralisation faibles. Par la suite, un traitement biologique a été effectué durant 20 jours, les taux globaux de minéralisation ont alors augmenté pour atteindre 81 et 68% pour respectivement la SMT et le TMP. Dans une dernière partie, nous avons procédé à la minéralisation de deux effluents industriels, contenant les antibiotiques étudiés, par couplage du procédé électro-Fenton et d’un traitement biologique. Les taux de minéralisation globaux obtenus sont de 81 et 89% pour respectivement l’effluent SMT et l’effluent TMP. Ce qui prouve la pertinence du procédé combiné, pour le traitement des effluents industriels
The occurrence of human and veterinary antibiotics in the aquatic ecosystem becomes a serious environmental problem. These compounds cannot be treated by wastewater treatment plants, resulting in their entry and accumulation to measurable levels in the environment. Over the last decade, the conventional biological processes were used for wastewater treatment, but did not appear to be enough effective when dealing with wastes containing antibiotics, owing to the important recalcitrance of these compounds. Therefore, the development of efficient methods to treat antibiotics is needed. The first part of this thesis is focused on the degradation of antibiotics by electro-Fenton process. This process consists in producing in situ strongly oxidizing species, hydroxyl radicals, allowing the total degradation of persistent and toxic organic compounds. Sulfamethazine (SMT) and trimethoprim (TMP) were selected as model compounds, because of their regular detection in the effluents of sewage plants, surface water and groundwater. In this first part, we examined the influence of various operating parameters, on the efficiency of electro-Fenton process. The optimal operating conditions necessary for the removal of the studied antibiotics, were also determined. Moreover, the aromatic intermediate products, generated during antibiotics degradation, were identified. Their evolution during electrolysis was also followed. The second part is devoted to the study of mineralization, of SMT and TMP, by the electro-Fenton process. The obtained results indicate that the yields of SMT and TMP mineralization were 91 and 85%, respectively after eighteen hours of treatment. The identification and monitoring of short chain carboxylic acids and released inorganic ions during the treatment, were carried out. Furthermore, based on the identified by-products, we proposed a plausible mineralization reaction pathway for SMT and TMP. The third part of this work concerns the study of the mineralization of considered antibiotics by a combined process coupling an electro-Fenton pretreatment and a biological degradation. SMT and TMP were pretreated by the electro-Fenton process, which led to their total degradation, with low levels of mineralization, ensuring significant residual organic content for a subsequent biological treatment. Afterwards, biological treatment was performed during 20 days and showed that the level of overall mineralization increased to reach 81 and 68% for SMT and TMP, respectively. In a last part, we carried out the mineralization of two industrial effluents containing SMT and TMP, by combining electro-Fenton and activated sludge treatment. Overall mineralization yields of the combined process of 81 and 89% were obtained for SMT effluent and TMP effluent, respectively. This result confirms the relevance of combined process, even for the treatment of industrial effluents

Este trabalho descreve o estudo da geração eletroquímica do H2O2 em eletrólito ácido (H2SO4 (0,1 mol L-1) + K2SO4 (0,1 mol L-1)) e eletrólito alcalino (KOH 1,0 mol L-1) utilizando eletrodo de difusão gasosa (EDG), sendo este fabricado com carbono Printex 6L e modificado com 3,0; 5,0 e 10,0% de ftalocianina de cobalto (II) ou cobre (II). Os experimentos foram realizados em uma célula eletroquímica de compartimento único contendo eletrodo de referência Ag/AgCl, contra eletrodo de Pt e como eletrodo de trabalho foi utilizado o EDG. Nos testes de eletrólise a potencial constante (-0,4 V ≤ E ≤ -1,4 V) durante 90 minutos com O2 pressurizado a 0,2 Bar, a concentração de H2O2 alcançou valor máximo de 178 mg L-1 a - 1,0 V (vs. Ag/AgCl) para o EDG não modificado em eletrólito ácido e em eletrólito alcalino, o valor máximo foi de 3.370 mg L-1 a -1,1 V (vs. Ag/AgCl). Quando incorporada a porcentagem de 5,0% de ftalocianina de cobalto (II) à massa do EGD verificou-se que a concentração de H2O2 alcança valor máximo em 331 mg L-1 a -0,7 V (vs. Ag/AgCl), o que representa um aumento de 86,0% no rendimento da produção de H2O2 em meio ácido, além de uma diminuição de 300 mV no potencial aplicado para formação da espécie oxidante. Para o estudo da degradação eletroquímica foram utilizados os corantes amaranto e tartrazina com concentração de 100 mg L-1. Para o estudo do processo eletro-Fenton homogêneo foram utilizados 0,05; 0,1 e 0,15 mmol de Fe2+ ou Fe3+ e para o processo eletro-Fenton heterogêneo em meio alcalino foi utilizado 0,15 mmol das nanopartículas do tipo Fe3-xCuxO4 (0 ≤ x ≤ 0,25). As eletrólises foram realizadas a potencial constante em -0,7 V (vs. Ag/AgCl) no EDG modificado com 5,0% de ftalocianina de cobalto (II) sob fluxo constante de O2 durante 90 minutos no processo eletro-Fenton homogêneo enquanto no processo eletro-Fenton heterogêneo o EDG não modificado foi utilizado e as eletrólises foram realizadas a -1,1 V (vs. Ag/AgCl). Todos os ensaios eletroquímicos foram realizados em um potenciostato PGSTAT- 302 acoplado a um com módulo de alta corrente BSTR-10A e controlado por meio do software GPES (Metrohm Autolab). As nanopartículas Fe3-xCuxO4 (0 ≤ x ≤ 0,25) foram caracterizadas por Análise de Ativação de Neutrons (AAN), DRX, BET, XPS e MET. As amostras dos corantes foram analisadas por espectrofotometria UV/Vis, cromatografia líquida de alta eficiência (CLAE) e teor de carbono orgânico total (COT). Em termos de descoloração, houve uma pequena diminuição no espectro dos corantes quando utilizado H2O2 eletrogerado em meio ácido o que não ocorre na degradação quando utilizado o processo eletro-Fenton homogêneo sendo mais evidente quando utilizado Fe2+, alcançando uma descoloração máxima de 80,0 e 99,2% respectivamente para os corantes amaranto e tartrazina. O decaimento da concentração por CLAE foi bastante eficiente quando utilizado o processo eletro-Fenton, com melhores resultados para Fe2+ e Fe3-xCuxO4 (x= 0,25) sendo a cinética dos processos de pseudo-primeira ordem. Foram identificados os subprodutos formados durante a degradação dos corantes durante o processo eletro-Fenton homogêneo. Os maiores valores de remoção de COT (67,3%) e consumo energético (CE) (370 kwh kg-1 foram obtidos para o processo utilizando íons Fe2+ e as nanopartículas Fe3-xCuxO4 (x=0,25) respectivamente para o corante amaranto. Os valores da concentração de ferro residual solúvel estão dentro do limite permitido segundo a Resolução CONAMA nº 430/2011. Para o processo eletro-Fenton heterogêneo, a concentração de H2O2 residual e consumida diminuiu e aumentou respectivamente com o aumento do valor de \"x\" na espinela da Fe3-xCuxO4 (0 ≤ x ≤ 0,25).
This work describes the electrogeneration of H2O2 study in acidic medium (H2SO4 (0.1 mol L-1) + K2SO4 (0.1 mol L-1)) and alkaline medium (KOH 1.0 mol L-1) using gas diffusion electrode (GDE), being these GDE manufactured with the Printex 6L carbon and modified with percentages of 3.0, 5.0 and 10.0% of cobalt (II) phthalocyanine or copper (II) phthalocyanine. The experiments were performed in an electrochemical cell single compartment containing the reference electrode Ag/AgCl, platinum counter electrode and the working electrode was used the GDE. In tests electrolysis at constant potential (-0.4 V ≤ E ≤ - 1.4 V) for 90 minutes pressurized with O2 at 0.2 Bar, H2O2 concentration reached a maximum value at 178 mg L-1 to -1.0 V (vs. Ag/AgCl) for GDE unmodified in acid electrolyte and alkaline electrolyte, the maximum value was 3,370 mg L-1 at potential -1.1 V (vs. Ag/AgCl).When incorporated percentage of 5.0% of cobalt (II) phthalocyanine to mass GDE, it is verified that the concentration of H2O2 reaches maximum value at 331 mg L-1 at -0.7 V (vs. Ag/AgCl), which represents increase in yield of 86.0% relative to Printex 6L carbon in acidic medium, addition to a decrease of 300 mV at potential applied to the formation of oxidizing species. To study the electrochemical degradation were amaranth and tartrazine dyes with concentration of 100 mg L-1. To study the homogeneous electro-Fenton process were used 0.05; 0.1 e 0.15 mmol de Fe2+ or Fe3+ and to heterogeneous electro-Fenton process in alkaline medium was used 0.15 mmol of Fe3-xCuxO4 (0 ≤ x ≤ 0.25) nanoparticles. The electrolysis were performed at constant potential -0.7 V (vs. Ag/AgCl) in the GDE modified with 5.0% of cobalt (II) phthalocyanine under constant flow of O2 for 90 minutes in the homogeneous electro-Fenton process while in the heterogeneous electro-Fenton process, GDE unmodified was used and the electrolysis were performed at -1.1 V (vs. Ag/AgCl). All electrochemical tests were performed using a potentiostat/galvanostat model PGSTAT 302 coupled to a BSTR-10A current booster and controlled by GPES software (Metrohm Autolab). The Fe3-xCuxO4 (0 ≤ x ≤ 0.25) nanoparticles were characterized by Neutron Activation Analysis (NAA), XRD, BET, XPS and TEM. The samples of the dyes were analyzed by spectrophotometry UV/Vis, high performance liquid chromatography (HPLC) and total organic carbon (TOC). In terms of discoloration, was a small decrease in the spectrum of the dye when used H2O2 in acidic medium which doesn\'t occur in the degradation when used homogeneous electro-Fenton process being more evident when used Fe2+, reaching a maximum discoloration of 80.0 and 99.2% respectively for amaranth and tartrazine dyes. The decay concentration by HPLC was very efficient when using the electro-Fenton process with better results for Fe2+ and Fe3-xCuxO4 (0 ≤ x ≤ 0.25) nanoparticles being the kinetics of the process of pseudo-first order. Were identified by-products formed during the degradation of dyes during the homogeneous electro-Fenton process. The higher values of TOC removal (67.3%) and energy consumption (EC) (370 kWh kg-1) were obtained to process using Fe2+ ions and Fe3-xCuxO4 (x= 0.25) nanoparticle respectively for amaranth dye. The values of residual soluble iron concentrations are within the permissible limit according to CONAMA Resolution nº 430/2011. To the heterogeneous electro-Fenton process, the residual and consumed concentration of H2O2 decreased and increased respectively with increasing value of \"x\" in the spinel of Fe3-xCuxO4 (0 ≤ x ≤ 0.25).

Cette étude porte sur l'application de différents procédés d'oxydation avancée, POA (plasma d'air humide, électro-Fenton, photo-Fenton et oxydation anodique avec BDD) pour le traitement des colorants de textile. La particularité de ces procédés tient à la génération dans le milieu d'entités très réactives et très oxydantes, les radicaux hydroxyles *OH qui sont capables d'oxyder n'importe quelle molécule organique jusqu'au stade ultime d'oxydation, c'est-à-dire la minéralisation (transformation en CO2 et H2O). Le plasma d'air humide a été appliqué pour l'oxydation d'un colorant azoïque, l'OD 61. Différents catalyseurs (Fe2+, Fe3+ et TiO2) ont été ajoutés dans leurs conditions optimisées afin d'améliorer les performances du système Glidarc. La combinaison des deux catalyseurs: Fe2+ et TiO2 a permis de décolorer 91% de l'OD 61 au bout de 3 heures et d'atteindre un taux d'abattement du COT de l'ordre de 52% après 10 heures de traitement. La méthodologie de la recherche expérimentale a été appliquée dans ce mémoire afin d'étudier l'influence de: l'intensité du courant, la concentration du colorant et le temps d'électrolyse sur la vitesse de disparition de l'OD 61 et afin de déterminer les conditions optimales de sa minéralisation. Dans les conditions optimales obtenues ([colorant] = 0,53.10-3 mol.L-1, I = 250 mA), le procédé électro-Fenton (EF) permet d'atteindre des taux de minéralisation de l'ordre de 98% dans le cas de l'OD 61 et l'AO 7 et de 88% dans le cas de l'indigo carmine. L'identification des produits intermédiaires au cours de l'électrolyse a permis de proposer un mécanisme de minéralisation de l'AO7. Les constantes cinétiques apparentes et absolues ont été déterminées. La dégradation de l'indigo a été étudiée par oxydation anodique avec BDD (OA-BDD) et par procédé photo-Fenton (PF). Cette étude a montré que l'électrolyse de l'indigo suit une cinétique de pseudo premier ordre et que le taux d'abattement du COT était de l'ordre de 97% et 63% respectivement avec OA-BDD et PF. Une étude comparative pour l'oxydation de l'AO 7 a été menée par trois procédés d'oxydation avancée: PF, OA- BDD et EF-Pt et EF-BDD. Cette étude a montré que le procédé photo-Fenton permet d'atteindre des taux d'abattement supérieurs à 90% après seulement 2 heures de traitement. Toutefois, le PF s'est révélé le plus coûteux suite à l'utilisation de la lumière artificielle UV et l'ajout des réactifs. Par ailleurs, le traitement d'un effluent réel issu de l'industrie de textile par le procédé électro-Fenton avec une anode de platine a permis la minéralisation presque totale du rejet initial (94% du COT initial ont été éliminés).

A problemática envolvendo os efluentes têxteis decorre principalmente da elevada coloração que apresentam, devido à presença de corantes que além de serem quimicamente estáveis, podem ser tóxicos e/ou carcinogênicos. Logo, quando são descartados in natura no meio ambiente causam problemas estéticos e, sobretudo, ambientais mesmo em baixas concentrações, além da possibilidade de serem nocivos à saúde humana e dos animais. Neste contexto, o objetivo deste trabalho foi estudar a degradação eletroquímica de dois corantes têxteis, Reativo Azul 19 (RA-19) e o Reativo Preto 5 (RP-5) via Oxidação Anódica (OA), utilizando ânodos de Diamante Dopado com Boro (DDB) suportados em titânio ou em nióbio, via processo Eletro-Fenton (EF) e pela combinação dos processos com H2O2 eletrogerado e OA (CP), usando um eletrodo de Carbono Vítreo Reticulado (CVR) como cátodo. As degradações foram realizadas em célula eletroquímica de um compartimento e em reator de fluxo do tipo filtro-prensa com dois compartimentos. A eficiência das degradações foi monitorada pelas técnicas de espectrofotometria no UV-VIS, Cromatografia Líquida de Alta Eficiência (CLAE) e análise do teor de Carbono Orgânico Total (COT). As variáveis estudadas foram densidade de corrente (10-100 mA cm-2 em célula e 4-41 mA cm-2 em reator), dopagem do eletrodo de DDB/Ti (5.000 e 15.000 ppm B/C), concentração inicial dos íons Fe2+ (0-0,10 mmol L-1) e dos corantes (10-250 mg L-1). As degradações dos corantes apresentaram uma cinética de pseudo ordem zero; exceto quando o corante RP-5 foi degradado pelo processo EF, sendo o melhor ajuste ao modelo de pseudo primeira ordem. Além disso, em iguais condições eletroquímicas o corante RP-5 foi degradado em menor tempo em relação ao RA-19; sendo que em todos os processos estudados os corantes foram totalmente removidos. Considerando a OA em célula com os eletrodos de DDB/Ti, a degradação foi positivamente influenciada pelo aumento da densidade de corrente e dopagem do eletrodo, especialmente em relação a cinética. Além disso, os corantes RA-19 e RP-5 foram completamente removidos em 35 e 50 min de eletrólise quando 100 mA cm-2 foi aplicada ao eletrodo de DDB/Ti dopado com 15.000 ppm relação B/C. Em 2 h, 37% em mineralização foi observado para ambos os corantes e a toxicidade do RA-19 diminuiu contra as bactérias Vibrio fischeri. Ainda nessa condição total mineralização foi alcançada após 8 h de degradação. A remoção de COT foi favorecida utilizando o reator contendo os eletrodos de DDB/Nb e CVR ao invés da célula eletroquímica, chegando a percentuais de 84 e 82% em 30 e 90 min para os corantes RA-19 e RP-5 que foram removidos em 7,5 e 5 min, respectivamente, quando a densidade de 41 mA cm-2 foi aplicada ao DDB/Nb durante a degradação via exclusivamente OA. Entre os processos realizados no reator, o EF foi o energeticamente mais favorável, promovendo remoção em COT de 60 e 74% para os corantes RA-19 e RP-5 com consumo energético de 204 e 208 kWh kg-1, além disso, a completa remoção dos corantes ocorreu em 15 e 7,5 min, respectivamente, quando o eletrólito continha íons Fe2+ na concentração de 0,10 mmol L-1 e aplicando-se -0,4 V vs Ag/AgCl ao eletrodo de CVR. Na degradação os corantes via CP o RA-19 e RP-5 foram completamente removidos em 30 e 15 min com mineralização de 72 e 82% em 90 min associada a consumos energéticos de 562 e 745 kWh kg-1, respectivamente, quando 41 mA cm-2 foi aplicada ao DDB/Nb. Por fim, concluiu-se que os resultados das degradações dos corantes foram promissores, já que rápida remoção dos corantes foi observada, além da parcial mineralização. Logo os processos propostos podem ser aplicados na remoção dos corantes em água; sendo necessários realizar mais estudos, principalmente em relação ao material eletródico e configuração do sistema eletroquímico visando a aplicação industrial.
The main problem involving the textile wastewater is theirs high coloration since they present dyes, which are chemically stable and can be toxic and/or carcinogenic. Therefore, when the textile wastewater are discarded in nature in the environment, even in low concentrations, they may cause not only aesthetic and environmental problems, but also can be harmful to human and animal health. In this context, the aim of the study was to evaluate the electrochemical degradation of two textile dyes, Reactive Blue 19 (RB-19) and Black 5 (RB-5) via Anodic Oxidation (AO) using as anodes Boron Doped Diamond electrodes (BDD) supported on titanium or niobium, via Electro-Fenton (EF) process and by combination of processes with electrogenerated H2O2 and AO (CP) using a Reticulated Vitreous Carbon electrode (RVC) as cathode. The degradations assays were carried out in an electrochemical cell with one compartment and in a filter-press flow reactor with two compartments. The efficiency of degradation was monitored by UV-VIS spectrophotometry, High Performance Liquid Chromatography (HPLC) and analysis of Total Organic Carbon (TOC). The variables studied were current density (10-100 mA cm-2 for cell and 4-41 mA cm-2 for reactor), doping of the BDD/Ti electrodes (5,000 e 15,000 ppm B/C), initial concentration of the Fe2+ ions (0-0,10 mmol L-1) and dyes (10-250 mg L-1). The kinetic results showed that the removal of dyes followed the model of pseudo zero order; except when the RB-5 dye was degraded by EF process, which the best fitted was to pseudo first order model. Furthermore, for equal conditions the RB-5 was degraded in less time in comparison to the RB-19. In addition, the dyes were fully removed in all the processes studied. Regarding the AO in cell with BDD/Ti, the degradation was positively influenced by the increasing in current density and doping of the electrode, primarily the kinetics parameters. In addition, total removal of RB-19 and RB-5 was achieved in 35 and 50 min of electrolysis when 100 mA cm-2 was applied to the electrode doped with 15,000 ppm ratio B/C. In 2 h, 37% in mineralization was attained for both dyes and the toxicity effect of the RB-19 decreased against the bacteria Vibrio fischeri. In this condition, total TOC removed was also reached after 8 h. The TOC removal was enhanced using the reactor fitted with BDD/Nb and RVC instead of the electrochemical cell, achieving TOC removal of 84 and 82% in 30 and 90 min for RB-19 and RB-5 which were removed in 7.5 and 5 min, respectively, when 41 mA cm-2 was applied to the BDD/Nb in the degradation exclusively via AO. Among the processes carried out in the reactor, the EF was the energetically most favourable since TOC removal of 60 and 74% for RB-19 and RB-5 with energy consumption of 204 and 208 kWh kg-1 were noted. In addition, the RB-19 and RB-5 were completely removed in 15 and 7.5 min, respectively, when the electrolyte containing 0.10 mmol L-1 of Fe2+ ions and -0.4 V vs Ag/AgCl was applied to CVR electrode. The combination of processes with electrogenerated H2O2 and AO for degradation of the dyes removed the RB-19 and RB-5 in 30 and 15 min with mineralization of 71.6 and 81.8% in 90 min associated to energy consumptions of 562 and 745 kWh kg-1 respectively, when 41 mA cm-2 was applied to BDD/Nb. Therefore, the degradation results of the dyes were promised since quickly removal of the dyes and partial mineralization were observed hence the proposed processes could be used to remove the dyes from water. However, more studies are needed to enable an industrial application, especially regarding the electrode material and configuration of the electrochemical system.

Este trabalho compara a utilização do tratamento eletrolítico e do tratamento Eletro-Fenton, em corrente alternada (CA), no chorume proveniente do aterro de Gramacho, no estado do Rio de Janeiro. O tratamento eletrolítico consiste em utilizar eletrodos de Fe em contato com a eletricidade, que em pH adequado, sofrem dissolução formando o agente coagulante in situ. O tratamento Eletro-Fenton consiste na geração de um dos componentes do reagente de Fenton pelo método eletrolítico. Nesse trabalho o reagente de Fenton é formado pelos íons ferro gerados pelo tratamento eletrolítico unindo-se ao peróxido de hidrogênio 30% adicionado exteriormente. Amostras do chorume foram caracterizadas pelos parâmetros pH, condutividade, salinidade, temperatura, turbidez, sólidos totais dissolvidos (STD) e Demanda Química de Oxigênio (DQO). O uso do tratamento eletrolítico só mostrou resultados de remoção para DQO e cor. Para garantir um melhor desempenho na remoção de DQO e cor e encontrar valores de remoção para a turbidez foi necessário o uso do tratamento Eletro-Fenton. Alguns parâmetros são importantes no uso dessa técnica, tais como pH, dosagem de peróxido, intensidade de corrente e tempo reacional. Os resultados obtidos para a remoção de DQO, cor e turbidez, foram respectivamente, 74%, 95% e 95%, nas condições operacionais: pH 4, dosagem de 5 mL de peróxido de hidrogênio a 30 %, intensidade de corrente de 2A e tempo reacional de 30 minutos. O tratamento Eletro-Fenton se mostrou mais favorável, pois o tratamento eletrolítico nas mesmas condições operacionais, só apresentou resultado de remoção de DQO que foi de 56%, mesmo sendo o consumo energético idêntico para ambos os processos (0,6 k W h m-3)

碩士
嘉南藥理科技大學
環境工程與科學系碩士班
96
Electro-Fenton process is one of advanced oxidation processes. This method applies H2O2 and ferrous ions to produce hydroxyl radical for oxidizing the contaminants.In this study,I choose electro-Fenton and Fenton-like processes to treat 2,6-dimethylaniline. The objectives of this study included：(1) to identify the ability of direct electrolysis in oxidizing pollutant; (2) to compare the oxidation efficiency of the electro-Fenton and Fenton-like processes; (3) to determine the influences of initial pH,ferric ion,current and hydrogen peroxide concentration on the oxidation of 2,6-dimethylaniline. Results show that oxidation efficiency of the electro-Fenton process is better than Fenton process.Increasing the ferric concentration and electric current will enhance the oxidation efficiency.When the electric current is increased to 5 A,the ferrous concentration decreased.Too much electric current will result in water electrolysis and reduce the current efficiency of ferric reduction and the refore increased power cost.Increasing the initial pH from 1.5 to 2.0,the ferrous concentration is increased.When the initial pH is increased to 3.0,the ferrous easily reacted with hydroxide and changed to become iron oxide and thus the ferrous concentration is decreased. The optimum experiment condition for electro-Fenton process were controlled as follows: [2,6-DMA]=1×10-3 M , [Fe3+]=1×10-3 M, [H2O2]=20×10-3 M, initial pH=2.0, current=1 A.

碩士
嘉南藥理大學
環境資源管理系
105
The purpose of this study is to investigate the Electro-Fenton process feasibility in the removal of Acetaminophen (ACT) from the wastewater. Electro-Fenton process was employed in order to achieve the best ACT degradation and removal. Acetaminophen,a non-prescription,analgesic,antipyretics,and anti-inflammatory drug(ex.Panadol),is defined by the Environmental Protection Administration as a new water contaminant or an "emerging contaminant" and is classified as one of the Pharmaceutical and Personal Care Products (PPCPs). As an emerging contaminant, ACT presents risks both in human health and ecosystem. ACT is also an Over-the-Counter (OTC) drug which indicates that its use is very convenient to any patient. Although this substance is very small and not very toxic, it does not mean that it will not have a negative impact on the environment and humans. Therefore, the objective of this study is to use Electro-Fenton process to remove ACT from simulated wastewater, and to facilitate practical applications. This study can be used as a reference by the future researchers. ACT degradation was examined by varying ferrous ion (Fe2+) concentrations and hydrogen peroxide (H2O2) concentrations with fixed current supply at 1.5A and fixed pH=2.0. ACT removal rate reached 96% when Fe2+ concentration is at 1.0mM and H2O2 concentration is at 20mM, based on Fe2+ concentration test. On the other hand, based on H2O2 concentration test, a 100% removal rate was acheived when Fe2+ concentration is at 0.8mM and H2O2 concentration is at 25mM. In conclusion, both conditions can be used in order to achieve a good ACT removal efficiency.

碩士
嘉南藥理科技大學
環境工程與科學系暨研究所
91
Electro-Fenton process is one of advanced oxidation processes; it was employed to the treatment of benzene compounds in the dissertation. Electrochemical destruction of the nitrobenzene and aniline were conducted to examine the influence of benzene substituents characteristics on the electrochemical oxidability of benzene compounds. In this study, a novel electrochemical method for treating wastewater containing benzene compounds was investigated. In the electrolytic cell, the organic compound was ionized or was oxidized by direct electrolysis on the anode. Meanwhile, this method applied H2O2 and ferrous ion to produce hydroxyl radical for oxidizes the contaminants, in which ferrous ion is regenerated via the reduction of ferric ion on the cathode. The objectives of this study included：(1) to identify the ability of direct electrolysis in oxidizing pollutant; (2) to determine the influences of initial pH, ferrous ion and hydrogen peroxide concentration on the oxidation of benzene compounds; (3) to compare the catalyzing ability of ferrous and ferric ions; (4) to identify the effects of inorganic anions on the electro- Fenton process; (5) to compare the oxidation efficiency of the electro-Fenton and Fenton processes. Results showed that the experimental conditions were controlled as follows, [ C6H5NO2] = 0.01 M, [C6H5NH2] = 0.01 M, Fe2+ = 1.8 x 10-3 M, H2O2 = 1.9 M, initial pH＝2.0, current density＝33.33 A/m2, after electrolyzing for 10 min, the removal efficiencies increased 40% compared of those Fenton treatment. The oxygen atom is strongly electronegative. It has tendency to attract electrons. Therefore direct electrolysis of aniline is more difficult than nitrobenzene. The oxidation rates of made oxidation of nitrobenzene no significant effect at low initial pH (pH=2.0 ~ 3.5). However, for the oxidation of aniline, the highest rate can be found at initial pH 3.5. When applying Fe3+ to electro- Fenton system, it needed five times of Fe3+ dosage to get the same oxidation efficiency compared to the system with Fe2+. This study selected four anions, namely H2PO4-, Cl-, NO3- and ClO4- to explore their effect on the process. Phosphate ions suppressed the nitrobenzene and aniline decomposition. The main reason for the suppression of phosphate ions is that will produce a complex reaction with ferrous ions and ferric ions, which lowers its ability to catalyze hydrogen peroxide.

碩士
國立中興大學
環境工程學系所
98
In this study, we apply electrochemical processes to the degradation of chlorophenols in aqueous media. The target pollutants 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP) were conducted by electrokinetic process (EK) and electro-Fenton process (EF)；and removal rate, mineralization and dechlorination for different processes were investigated. Based on the results, Electro-Fenton system has the best rate of producing ferrous ion and hydrogen peroxide at electric density of 0.75 mA/cm2 and air flow of 0.7 mL/min. The synthesis mass of hydrogen peroxide by EF process followed linear relation with time at the first 30 min which was 0.65 mg-H2O2/min. According to the results of batch experimental, all electrochemical processes have great efficiency in the removal of chlorophenols in aqueous media in this study. Among these processes, the Electro-Fenton process have the best treatment efficiency, that 2,4-DCP and PCP residual rate was 19.8 and 35.9%, and mineralization efficiency was 78.7 and 63.8%, respectively after 180 min. Lengthening treatment time can enhance the removal efficiency, that increase 10.2 and 1.3 times for 2,4-DCP and PCP, respectively. Under the same operating conditions, the order of removal efficiency is EF>EK4 (Electrokinetic, pH 4)>EK10 (Electrokinetic, pH 10)>EFL (Electo-Fenton-like)；the mineralization efficiency is EF> EK4> EK10> EFL; the dechlorination efficiency is EF>EK4≒EFL>EK10. Application of optimum conditions in treatment of true groundwater pollution, the removal rate and mineralization efficiency was 81.29 and 77. 50% for 2,4-DCP and 77.49 and 54.71% for PCP, respectively. Proved by the experimental results, Electro-Fenton process is really suitable for remediation of chlorophenols in groundwater.

碩士
國立成功大學
化學工程學系碩博士班
95
The primary objective of this dissertation is to study the treatment of chelate (citrate), reductant ( hyposphosphite ) and nickel ion from electroless nickel plating wastewater. The Fenton’s reagent was employed to remove COD of citrate and oxidize hypophosphite to phosphite or phosphate, then removed Nickel by chemical coagulation. In trinary system (including hypophosphite, nickel ion and citrate), the hypophosphite could be oxidized entirely by Fenton’s reagent at pH2.0~4.0 and by the following molar ratio of dosage: hypophosphite：citrate：Fe(II) = 1：1：1.5. Only 80% COD major contributed by citrate was removed due to the iron ions are inhibited by phosphite and phosphate. On the other words, the poisoned iron ions could not catalyze H2O2 and remove COD. In binary system (citrate and nickel ion), The Electro-Fenton was employed. Because the Fenton reaction would produce much amount of sludge, low concentration of Fe(II) was used in Electro-Fenton. The molar ratio of dosage in this stage: Fe(II)：citrate：Ni：H2O2=1：5：5：54 and about 90% COD was removed. Afterwards effect of pH on current density and configuration of cathode was discussed this system. The optimum current density is 190 A/m2 at pH 2 and 3. If we change the configuration of cathode from tube to net and the COD removal was increased from 90% to 95% due to mass transfer resistant was decreased. In modeling electroless plating wastewater, the effect of hypophosphite on the binary system was discussed. In different hypophosphite concentration, 95% COD could be removed by electro-Fenton process, but only 20% COD was removed by Fenton process. The concentration of iron ions is decreased with reaction time because the iron ions were precipitated by oxidized phosphate. The residue COD in solution almost keep constant. Finally, the conditions of the treatment of modeling wastewater were performed to treat practical electroless plating wastewater. The dosage of iron have to increase from 1100 ppm to 3300 ppm resulted in the large amount of phosphate. If the Fe (III) rather than Fe(II) was employed, the removal of COD would increase from 80% to 90%.

碩士
臺灣大學
化學工程學研究所
98
Advanced oxidation process is the best method for wastewater treatment. According to the different classification of reaction mechanisms, Electro-Fenton process and Photo-catalytic reaction have the most common applications. In this study, the AP-CC represented that the anode was Platinum (Pt) and the cathode was carbon cloth which was fed with oxygen. The applied voltage was set to produce H2O2 at the cathode. When the Fe2+ was added into the solution, the system was called AP-CC-Fe2+ system in this research. Afterward, the iron (Fe) replaced the Pt as the anode with zero applied voltage and the system was named AF-CC-Iapp=0mA. Besides, the Fe was oxidized to generate current and Fe2+, and the organics will be decomposed by Fenton process. The flux of oxygen, the initial pH value, and the reaction temperature were discussed in this experiment of H2O2 formation. The average formation rate of H2O2 is proportional to the applied current. Moreover, the electrolysis constant is 10-4 M.A-1min-1 according to the electrolyzing p-phenylenediamine experiment. p-Phenylenediamine causes the quite serious environmental pollution because of its popular applications in hair dye and artificial fiber synthetic industry. The initial pH value and the Fe2+ concentration were discussed in AP-CC-Fe2+ system. The optimum condition is pH=3 and [Fe2+]=3mM, and the overall rate constant is 5.35×10-2min-1. According to the AF-CC-Iapp=0mA system in the self electro-generative process, the influences of the initial pH value and the flux of oxygen on degradation rate were studied. The degradation efficiency was enhanced with the condition of pH=7 and [O2]=60ml.min-1, and the overall rate constant is 2.85×10-2min-1. In the AF-CC-Iapp=0mA system, p-phenylenediamine can be degraded by self electro-generative process without applied voltage and Fenton reagents.

碩士
國立成功大學
化學工程學系碩博士班
99
Hydroxyl radical is very reactive, underlying the chemistry of advanced oxidation processes (AOPs) for degrading organic compounds in water. Among various AOPs, Fenton’s reagent has been known to be an effective and simple oxidant. It is found that the Fenton reaction can be an efficiency enhanced in photo-electro-Fenton process since ferric may complex with certain target compounds or byproducts, especially those acting as ligands, produced by UVA light and current. The new design of our system came from the concept of promoting the ferric reduction rate, which can increase the amount of hydroxyl radicals. In this study investigated photo-electro-Fentonto oxidize 1 mM of 2,6-dimethylaniline and 1.6 mM pyridine. This investigation reveals that photo-electro-Fenton can completely degrade 1 mM of 2,6-dimethylaniline. However only 83.44 % of TOC removal can be eliminated after 240 min of reaction at of 200 mg L-1 of Fe2+, pHi=2, 1800 mg L-1 H2O2, CDc=23.19 A m-2. 94% pyridine degradation and 70% TOC can be removed after 240 min of the reaction in the presence of 50 mg L-1 Fe2+, pHi=2, 1600 mg L-1 H2O2, CDc=4.64 A m-2. In addition, we also calculated the observed reaction constant k1 and k2 with different condition of operation using pseudo-first-order reaction. Futhermore, the mechanism of 2,6-dimethylaniline and pyridine was proposed in this study. It is also found that 2,6-dimethylaniline can not completely be oxidized to carbon dioxide but transformed to some intermediates which have similar like of 2,6-dimethylaniline and No heterocyclic intermediate in the pyridine system.

碩士
嘉南藥理大學
環境資源管理系
106
In this study, the dyeing and finishing wastewater of Reactive Yellow 145 (Reactive Yellow 145, RY145) was treated by the electric Fenton program. The optimum parameters were used to investigate the treatment and chroma removal ability. The system was based on cathode stainless steel and insoluble anode materials. For the material of the two electrodes of yin and yang, the amount of iron added is controlled during operation, and sufficient ferrous ions are generated by the reducing ability of the cathode to reduce the addition of the reaction catalyst to reduce the generation of iron sludge. According to the results of the study, in the Electro-Fenton process, the current can increase the degradation rate of Reactive Yellow 145. The increase of ferrous ion and hydrogen peroxide concentration should also pay attention to the concentration of the added amount, which will affect the oxidizing ability of the Fenton system for organic matter. Experiments were performed with pH=2 and current 1.5A as fixed conditions. The ferrous ion concentration test showed that the optimal ferrous ion concentration was 0.1 mM and the hydrogen peroxide optimal parameter was 30 mM having a RY 145 removal rate of 91%. Hydrogen peroxide concentration test, hydrogen peroxide conditions for 30mM, the best parameter for ferrous ions is 0.01mM, the removal rate is 94%. Both conditions can achieve a good removal efficiency of Reactive Yellow 145.

碩士
國立臺灣大學
環境工程學研究所
102
Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) are a class of drugs widely provides analgesic (Pain-killing) and antipyretic (Fever-reducing) effects. Ketoprofen (KET), [2-(3-benzoylphenyl)propanoic acid] is one of the propionic acid class of NSAIDs. KET is mainly used for treatment of musculoskeletal pain. KET can also be used for treatment of some nerve pain such as sciatica. In recent years, the amount of use for NSAIDs is increasing rapidly in developed countries. Therefore, the presence of these pharmaceuticals in water system becomes a growing problem in these decades. Since the sewage treatment plant can’t eliminate the NSAIDs efficiently, the treatment which usually applied for the removal of NSAIDs is Advanced Oxidation Process (AOP). Advanced oxidation process such as Ozonation, Fenton/Fenton-like, Photocatalysis or Electrolysis all using the hydroxyl radical (•OH) to mineralized the target compounds in water. The goal of this research is to find out the removal efficiency of KET in water by using Electro-Fenton process (EF). Using HPLC to quantified the residual KET in water solution after the EF process. Applying response surface methodology (RSM) to approach the optimal operation conditions. In the background test of Electrolysis and Fenton reaction, four different operating parameters (current level, pH, hydrogen peroxide [H2O2] and iron [Fe2+] dosage) were tested. The removal efficiency increased with the decreasing pH and increasing H2O2 and Fe2+ dosage. In the EF batch experiments, four operating parameters, current level, pH, H2O2 and Fe2+ dosage were tested. The removal efficiency increased with pH decreasing and increasing H2O2 dosage, which followed the same patterns as Fenton experiment. However, the reduction reaction in cathode contributed to less Fe2+ required for Electro-Fenton process. The Fe3+ was converted to Fe2+ in this reduction process. The current level didn’t affect the removal efficiency significantly when applying enough H2O2 and Fe2+. By choosing pH range from 2 to 4, H2O2 and Fe2+ dosage from 0.01 to 0.1 mM as the varieties in the response surface methodology, tested a sequence of the design experiments. The removal efficiency can reach 96% at pH=2, H2O2=0.1 mM and Fe2+=0.1 mM. In conclusion, the EF process is a decent method for the elimination of KET.

碩士
國立中興大學
環境工程學系所
100
Fenton oxidation process, which is one of the advanced oxidation processes, is performed by reacting ferrous ions with hydrogen peroxide to generate hydroxyl radical (‧OH) under acidic conditions. This process produces a high oxidation ability, non-selective hydroxyl radical which can oxidize a variety of organic matter in the wastewater. Further the powerful oxidizing capability to oxidize organic matter of the wastewater to carbon dioxide and water. In the present study, the application of Electro-Fenton process for the degradation of antibiotic Trimethoprim (TMP) wastewater with the appropriate parameters to explore the mineralization and removal capacity was investigated. The material of cathode and anode were, respectively, stainless steel net and stick used in the system. H2O2 can be electro-generated by reduction of oxygen in the cathode, and ferrous ions can be produced by oxidation of iron in the anode. Based on the results of background experiment, the optimal parameters for electro-generated H2O2 was at current of 1.5 A and air flow of 0.7 NL/min. Under these conditions, the maximum remnant of H2O2 was 57.32 mg/L in 180 min of operation. The formation rate was 0.05582 mg-H2O2/min in 30 min before the reaction. Results show that the Fenton process can degrade 10 mg/L TMP by using 10 mg/L ferrous ions and 50 mg/L hydrogen peroxide in acidic solution after 60 min. The TMP removal rate is 19.3 %. When the treatment time is extended to 360 min, the TMP, COD and TOC removal rates are 32.1, 29.2, and 28.1 % respectively. Electro-Fenton oxidation process with optimal parameters found in generation experiment, the TMP removal rate is 66.0 % after 180 min. When the treatment time is extended to 360 min, the TMP, COD and TOC removal rate are 71.8, 59.4, and 53.6 % separately. The results are significantly better than traditional Fenton oxidation process. The COD removal rate and mineralization are also enhanced. Electro-Fenton oxidation process is conducive to the removal of TMP, and enhance the mineralization.

碩士
淡江大學
水資源及環境工程學系碩士班
97
The treatment of Latex coating wastewater usually faces large quantity of sludge and easily blockage of the system. This study compared Electrochemical, chemical coagulation, and Fenton method in the wastewater treatment, and try to find an appropriate process for the Latex wastewater treatment. The Parameters considered in the electrochemical coagulation procedures include voltage, current, pH, addition sodium chloride concentration and reaction time. The chemical coagulation used ferric chloride and aluminum sulfate as coagulant. The turbidity removal efficiency for three procedures with the wastewater different initial pH was compared. The Fenton method that uses the hydrogen peroxide as oxidant for the treatment of wastewater and its removal efficiency is relatively less. For chemical coagulation its removal efficiency is good for a wide range of pH of the wastewater. Electrochemical coagulation process was found that increase turbidity removal efficiency by increase voltage and electrolyte concentration. With the operation parameters of chemical coagulation are initial pH=7 and ferric chloride concentration = 500mg / L, and aluminum sulfate concentration=1000mg/L and the initial pH =7. The removal efficiency for turbidity, color, chemical oxygen can reach 99%. Electrochemical coagulation control voltage 18V in neutral, electrolyte add 500mg / L, the reaction time is16 minutes, can provide removal efficiency up to 99% , When the aluminum and iron were used as anion, the iron anode occur depolarization while the aluminum anode is more stable than iron.

碩士
輔英科技大學
環境工程與科學系碩士班
107
In this study, the wastewater containing Acid Red 18 dye was treated by electro-Fenton process, and the Acid Red 18 was a kind of mono-azo dye. Various operating conditions, such as H2O2 concentration, pH value, applied voltage,electrolyte concentration and type,affected the degradation of Acid Red 18 were discussed. The degradation of Acid Red 18 was described by pseudo-first order reaction kinetics. The dynamic flow reactor was adopted in this study. The materials of cathode and anode plates are stainless steel and graphite, respectively. The Fe3+ species was reduced to Fe2+ in electro-Fenton process, and the additive amount of Fe2+ used in Fenton process decreased, thereby cut down the sludge produced. In this study, Acid Red 18 concentration (1.65mM), ferrous ion concentration (2.5mM) and reaction time (30min) remain unchanged. According to the results, the degradation of Acid Red 18 is fastest when the concentration of H2O2 is 30mM and the residual concentration is also lowest. The regulation of pH is quite important in electro-Fenton process. When the pH is higher or lower than 3, the degradation rate constant is lower than that at pH3. The appropriate applied voltage in our electro-Fenton system is around 10V. It was found the degradation mechanism depended on applied voltage. When the electrolyte concentration is controlled among 0.2~0.5mM,the higher electrolyte concentration is, the faster Acid Red 18 degrades. For different kind of electrolyte, Acid Red 18 degrades faster in wastewater containing monovalent electrolyte than bivalent electrolyte.

碩士
國立中興大學
環境工程學系所
101
Fenton oxidation treatment that is one of advanced oxidation processes (AOPs) is a common and effective method. It is carried out under acidic condition through hydrogen peroxide and ferrous ions in the reaction. The oxidation process produces a high oxidizing power and non-selectivity hydroxyl radical (HO ‧), which can decompose a variety of organic pollutants in wastewater in the process. In the research, the application of Electro-Fenton process for the degradation of antibiotic Sulfamethoxazole (SMX) wastewater with the appropriate parameters to explore the mineralization and removal capacity was investigated. Stainless steel net and iridium oxide were regarded as the material of cathode and anode respectively in our system. H2O2 was electro-generated by reduction of oxygen in the cathode, meanwhile controling the added amount of ferrous ion in the operation. The use of the reducing ability of the cathode to generate H2O2 and sufficient ferrous ion catalyst to be added was to reduce costs and to minimize the generation of sludge. Based on the results of background experiment, the optimal parameters for electro-generated H2O2 were at current of 1.25 A and air flow of 1.0 NL/min. Under these conditions, the maximum remnant of H2O2 was 9.49 mg/L in 180 min of operation. The formation rate was 0.328 mg-H2O2/min in 30 min without the reaction. The results showed that, under direct electrolysis of the electrolytic system for SMX wastewater, the removal rate was only 4.97 %. And the Fenton oxidation process in acidic solution (pH = 3), treating an aqueous solution of 10 mg /L SMX, the best hydrogen peroxide and ferrous ion concentration was 50 mg / L and 3 mg / L respectively, and the SMX removal rate was 76.48 % after 60 min. By Electro-Fenton oxidation process with optimal parameters found in generation experiment, the SMX removal rate was 82.46 % after 180 min. Finally when the treatment time was extended to 6 hours, the direct electrolysis, Fenton and E-Fenton removal rates were 11.06 %, 75.54 % and 89.72 %. The COD removal rate was 50.67 % which is also the best by E-Fenton. Therefore, the results indicate Electro-Fenton is superior to the traditional Fenton treatment method not only on the removal of SMX, but also on the removal of COD.

碩士
國立中興大學
環境工程學系所
106
Emerging contaminants are mainly generated through human activities and are not easily degraded in the environment. Various types of environmental hormones, such as pharmaceuticals and personal care products (PPCPs) are included. However, it is difficult to degrade PPCPs in a sewage water treatment system so that they can easily enter the water environment and cause pollution. Advanced oxidation processes (AOPs), such as persulfate and Fenton process, are oxidation treatment that we often use to remove organic pollutants. In this study, five advanced oxidation processes such as Fenton, Electro-Fenton, Electro-SPS, E-F-SPS and E-F-SPS-H2O2 were used to investigate the effects of hydroxyl radical and sulfate radical on SMX degradation efficiency. The results indicates that Electro-Fenton process has completely degrade SMX. The removal of SMX reached 100 % in 15 minutes and total organic carbon(TOC) also reached a 40.38 % removal rate in 120 minutes by adding 0.05 mM of Fe2+ and 1.25 mM of H2O2. In contrast, SMX removal efficiency of the Electro-SPS system without addition of H2O2 takes 60 minutes to complete the degradation, and the total organic carbon removal rate could achieve only about 29.65 % in 120 minutes. From the experimental results, it is found that the degradation of SMX is more favorable in a system containing H2O2 to produce OH·.

博士
國立成功大學
化學工程學系碩博士班
96
A new approach of photoelectro assisted Fenton process has been developed in our laboratory. It is found that the Fenton reaction can be efficiency enhanced in photoelectro assisted Fenton process since Fe(Ⅲ) may complex with certain target compounds or byproducts, especially those acting as ligands, produced by UVA light and current. The new design of our system came from the concept of promoting the ferric reduction rate, which can increase the amount of hydroxyl radicals. Literatures reported that oxalic, formic and acetic acids are the major products of aromatic compound degradation, which can complex with ferric ions. These complexes typically have higher molar absorption coefficients in the UV and visible regions to generate ferrous ions. Meanwhile, the ferrous ion is regenerated via the reduction of ferric ion on the cathode. However, the reaction mechanism of ferric ion reduction is still unclear. Therefore, a functional reactor was designed to save energy and to clarify the mechanism of ferric reduction with UVA light and electricity. A new electro-chemical cell was developed to increase the working area and promote the current efficiency. The operation parameters, such as single and double electrode effect, electrode distance, initial pH, Fe2+/H2O2 molar ratio, applied current, H2O2 feeding mode were investigated, firstly. Then the test of biodegradability (BOD/COD; BOD/TOC) was used to explore the effect of Fenton, electro-Fenton and photoelectro assisted Fenton process. Finally, in this dissertation, the intermediate of oxidation process was identified and the mechanisms were proposed.