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Partager le résultat de cette recherche Interroger des sources externesElimination des polluants organiques par méthodes physicochimiques et photochimiques en milieux aqueux. / Abdessemed Ala
Titre : Elimination des polluants organiques par méthodes physicochimiques et photochimiques en milieux aqueux. : Cas de l’éthyle violet et du rouge congo (séparés et mélangés) et de la monochloramine Type de document : texte imprimé Auteurs : Abdessemed Ala, Auteur ; Kamel Djebbar, Auteur Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2016 Importance : 224 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Éthyle Violet Rouge Congo Mochloramine TiO2 Charbon actif ZnO Adsorption Rayonnement UV Photolyse H2O2 NaOCl •OH Ethyl violet Congo red Monochloramine Activated carbon UV radiation Photolysis Violet Ethyle) (Congo Rouge) المونوكلرمين (NH2Cl) (PC500 TiO2) كربون منشط (ZnO) إدمصاص أشعة فوق بنفسجية (H2O2) (NaOCl) (•OH ) (•Cl) Index. décimale : 540 Chimie et sciences connexes Résumé : The aim of this research is to study the decolorization of two dyes separated and in a mixture by physico-chemical processes (adsorption, TiO2 and CA-ZnO) and photocatalytic processes like: TiO2/UV and CA-ZnO/UV. Another study has been led on the degradation of Monocloramine in homogeneous phase via direct UV photolysis, H2O2/UV and
NaOCl/UV. Treated separately, both dyes have shown an appreciable adsorption on the two supports and that this process is well represented by an apparent kinetic of order 2.
Besides, Congo Red and Ethyl Violet are described by isotherms of type L and S respectively and that process is also well represented by the model of Langmuir for Ethyl Violet and Redlish-Peterson of Congo Red. On the other hand, the photocatalytic system led via TiO2/UV has been efficient toward both dyes and this process follows an apparent
rate constant of order 1. In another part, this process is well described by the kinetic model of Langmuir-Hinshelwood and that oxidation process occurs, mainly, in surface. The inhibition process has been demonstrated by alcohols proving thereby that radicals •OH are the main oxidation route. The photoproducts issued from the decolorization of the two dyes have been identified using masse spectroscopy technic. This has permitted to establish a mechanism of degradation for the two dyes. Same efficiency is obtained using CAZnO/UV process (CA: activated carbon issued from olive cakes). In another side and in the mixture, the treatment of the two dyes by both systems has, shown that the efficiency decreases as the concentration of the other added dye increases. Indeed, the addition of the second substrate slows down the disappearance speed of the other. The kinitics model
remained unchanged for the two processes (2nd order for adsorption and 1 st order for photocatalysis) The last part treats the degradation of the Monochloramine which occurs via direct UV photolysis in presence of two lamps:
BP (254 nm) and MP (200-600 nm).
The obtained results have been significant. Furthermore, these results have been greatly enhanced mainly by H2O2/UV. However, for NaOCl/UV system we could mention that the disappearance rate slows down because of the formation of photoproducts such as: Mono, Di and Trichloramines. Moreover, the process is well described by an apparent kinetic of order 1 and those photoproducts identified in H2O2/UV, NaOCl/UV and direct photolysis systems are nitrates and nitritesDiplôme : Doctorat en sciences En ligne : ../theses/chimie/ALA6959.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10358 Elimination des polluants organiques par méthodes physicochimiques et photochimiques en milieux aqueux. : Cas de l’éthyle violet et du rouge congo (séparés et mélangés) et de la monochloramine [texte imprimé] / Abdessemed Ala, Auteur ; Kamel Djebbar, Auteur . - جامعة الإخوة منتوري قسنطينة, 2016 . - 224 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Éthyle Violet Rouge Congo Mochloramine TiO2 Charbon actif ZnO Adsorption Rayonnement UV Photolyse H2O2 NaOCl •OH Ethyl violet Congo red Monochloramine Activated carbon UV radiation Photolysis Violet Ethyle) (Congo Rouge) المونوكلرمين (NH2Cl) (PC500 TiO2) كربون منشط (ZnO) إدمصاص أشعة فوق بنفسجية (H2O2) (NaOCl) (•OH ) (•Cl) Index. décimale : 540 Chimie et sciences connexes Résumé : The aim of this research is to study the decolorization of two dyes separated and in a mixture by physico-chemical processes (adsorption, TiO2 and CA-ZnO) and photocatalytic processes like: TiO2/UV and CA-ZnO/UV. Another study has been led on the degradation of Monocloramine in homogeneous phase via direct UV photolysis, H2O2/UV and
NaOCl/UV. Treated separately, both dyes have shown an appreciable adsorption on the two supports and that this process is well represented by an apparent kinetic of order 2.
Besides, Congo Red and Ethyl Violet are described by isotherms of type L and S respectively and that process is also well represented by the model of Langmuir for Ethyl Violet and Redlish-Peterson of Congo Red. On the other hand, the photocatalytic system led via TiO2/UV has been efficient toward both dyes and this process follows an apparent
rate constant of order 1. In another part, this process is well described by the kinetic model of Langmuir-Hinshelwood and that oxidation process occurs, mainly, in surface. The inhibition process has been demonstrated by alcohols proving thereby that radicals •OH are the main oxidation route. The photoproducts issued from the decolorization of the two dyes have been identified using masse spectroscopy technic. This has permitted to establish a mechanism of degradation for the two dyes. Same efficiency is obtained using CAZnO/UV process (CA: activated carbon issued from olive cakes). In another side and in the mixture, the treatment of the two dyes by both systems has, shown that the efficiency decreases as the concentration of the other added dye increases. Indeed, the addition of the second substrate slows down the disappearance speed of the other. The kinitics model
remained unchanged for the two processes (2nd order for adsorption and 1 st order for photocatalysis) The last part treats the degradation of the Monochloramine which occurs via direct UV photolysis in presence of two lamps:
BP (254 nm) and MP (200-600 nm).
The obtained results have been significant. Furthermore, these results have been greatly enhanced mainly by H2O2/UV. However, for NaOCl/UV system we could mention that the disappearance rate slows down because of the formation of photoproducts such as: Mono, Di and Trichloramines. Moreover, the process is well described by an apparent kinetic of order 1 and those photoproducts identified in H2O2/UV, NaOCl/UV and direct photolysis systems are nitrates and nitritesDiplôme : Doctorat en sciences En ligne : ../theses/chimie/ALA6959.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10358 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité ALA/6959 ALA/6959 Thèse Bibliothèque principale Thèses Disponible
Titre : Etude comparative de la dégradation de colorants de la famille des triphénylméthanes par voies photochimique et sonochimique en solution aqueuse homogène et hétérogène. Type de document : texte imprimé Auteurs : Seyfeddine Bendjabeur, Auteur ; Razika Zouaghi, Directeur de thèse Mention d'édition : 10-mars-19 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 251 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Chimie: Chimie Analytique et Environnement Colorant adsorption Photolyse Procédés d’Oxydations Avancée H2O2 UV TiO2 Photocatalyse sonolyse dye photolysis advanced oxidation processes photocatalysis sonolysis صبغ امتزاز تحلل ضوئي عمليات أكسدة متطورة 2H20 الأشعة فوق البنفسجية و تحفيز ضوئي تحلل صوتي Index. décimale : 540 Chimie et sciences connexes Résumé : This study focused on the elimination of three dyes by several advanced sonochemical and photochemical oxidation processes in a homogeneous and heterogeneous medium as well as by direct photolysis at 254 and 365 nm. In most of the cases studied, a pseudo-first order kinetic law applies correctly to a large part of the reactions. The results obtained in this study indicated that photolysis (UV only) was found to have little effect on the degradation of the three dyes. The removal efficiency can be improved by increasing the intensity of the photonic flux or by decreasing the initial concentration of pollutant.
The coupling of H2O2/UV increases considerably the degradation rate of the three dyes, the efficiency is enhanced by raising the dose of H2O2 up to a limit imposed by the self-inhibition reactions. The DT-DFT method allowed recalculating the theoretical UV-Visible spectra of the three dyes which are comparable to that obtained experimentally. Adsorption and heterogeneous Photocatalysis were influenced by various factors (initial substrate concentration, catalyst type and loading, pH of the solution, addition of hydrogen peroxide, and the presence of inorganic salts). The results showed that the degradation yield of the three dyes is very high when using TiO2-P25, where a complete photocatalytic degradation of 10 mg L-1 of GV, BF and AF was obtained in 25, 30 and 50 minutes in the presence of 1 g L-1 of TiO2 Degussa P25 at natural pH. First-order kinetics described the photocatalytic reaction of the three substrates andthe Langmuir-Hinshelwood model correctly described the photocatalysis processes of the substrates tested. The comparison between various types of catalysts (Degussa P25, Millenium PC500, PC105, PC100, and PC50) gave varied results but Degussa P25 was the most efficient photocatalyst from which it was chosen for this study. The optimum catalyst concentration was 1 g L-1 of TiO2 with an initial concentration of 10 mg L-1 of dye. Finally, the sonochemical degradation of GV by sonolysis at 516 kHz shows that this method is effective for the degradation of this dye. However, this process can be affected by several parameters including, applied electrical power, initial substrate concentration, pHof the solution, the addition of H2O2 and S2O82- and the presence of someinorganic ions.Note de contenu : Annexe.
Diplôme : Doctorat En ligne : ../theses/chimie/BEN7567.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11405 Etude comparative de la dégradation de colorants de la famille des triphénylméthanes par voies photochimique et sonochimique en solution aqueuse homogène et hétérogène. [texte imprimé] / Seyfeddine Bendjabeur, Auteur ; Razika Zouaghi, Directeur de thèse . - 10-mars-19 . - جامعة الإخوة منتوري قسنطينة, 2019 . - 251 f. ; 30 cm.
Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Chimie: Chimie Analytique et Environnement Colorant adsorption Photolyse Procédés d’Oxydations Avancée H2O2 UV TiO2 Photocatalyse sonolyse dye photolysis advanced oxidation processes photocatalysis sonolysis صبغ امتزاز تحلل ضوئي عمليات أكسدة متطورة 2H20 الأشعة فوق البنفسجية و تحفيز ضوئي تحلل صوتي Index. décimale : 540 Chimie et sciences connexes Résumé : This study focused on the elimination of three dyes by several advanced sonochemical and photochemical oxidation processes in a homogeneous and heterogeneous medium as well as by direct photolysis at 254 and 365 nm. In most of the cases studied, a pseudo-first order kinetic law applies correctly to a large part of the reactions. The results obtained in this study indicated that photolysis (UV only) was found to have little effect on the degradation of the three dyes. The removal efficiency can be improved by increasing the intensity of the photonic flux or by decreasing the initial concentration of pollutant.
The coupling of H2O2/UV increases considerably the degradation rate of the three dyes, the efficiency is enhanced by raising the dose of H2O2 up to a limit imposed by the self-inhibition reactions. The DT-DFT method allowed recalculating the theoretical UV-Visible spectra of the three dyes which are comparable to that obtained experimentally. Adsorption and heterogeneous Photocatalysis were influenced by various factors (initial substrate concentration, catalyst type and loading, pH of the solution, addition of hydrogen peroxide, and the presence of inorganic salts). The results showed that the degradation yield of the three dyes is very high when using TiO2-P25, where a complete photocatalytic degradation of 10 mg L-1 of GV, BF and AF was obtained in 25, 30 and 50 minutes in the presence of 1 g L-1 of TiO2 Degussa P25 at natural pH. First-order kinetics described the photocatalytic reaction of the three substrates andthe Langmuir-Hinshelwood model correctly described the photocatalysis processes of the substrates tested. The comparison between various types of catalysts (Degussa P25, Millenium PC500, PC105, PC100, and PC50) gave varied results but Degussa P25 was the most efficient photocatalyst from which it was chosen for this study. The optimum catalyst concentration was 1 g L-1 of TiO2 with an initial concentration of 10 mg L-1 of dye. Finally, the sonochemical degradation of GV by sonolysis at 516 kHz shows that this method is effective for the degradation of this dye. However, this process can be affected by several parameters including, applied electrical power, initial substrate concentration, pHof the solution, the addition of H2O2 and S2O82- and the presence of someinorganic ions.Note de contenu : Annexe.
Diplôme : Doctorat En ligne : ../theses/chimie/BEN7567.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11405 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BEN/7567 BEN/7567 Thèse Bibliothèque principale Thèses Disponible
Titre : Photodegradation des produits pharmaceutiques induite par les complexes organiques de Fer(III) en solution aqueuse. Type de document : texte imprimé Auteurs : Imane Ghoul, Auteur ; Nadra Debbache, Directeur de thèse Mention d'édition : 15-janv-20 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2020 Importance : 226 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Chimie: Chimie Analytique et Environnement Diclofénac Aspirine Carbamazépine Fe(III)Cit Fenton photolyse Diclofenac Aspirin Photolysis ديكلوفيناك الأسبرين كاربامازيبين التحلل الضوئي Index. décimale : 540 Chimie et sciences connexes Résumé :
This work is a contribution to the photodegradation of three pharmaceutical compounds:
diclofenac (DCF), aspirin (ASP) and carbamazepine (CBZ) induced by organic complex of Fe(III) (Fe(III)Cit) in homogeneous phase under simulated and sunlight. A first part was devoted to the synthesis and characterization of Fe(III)Cit complex, which confirms its stability, its stoichiometry, while the effect of light irradiation revealed its photolysis, which generated the HO• radical. This oxidizing species has shown its effectiveness in the elimination of PP. In the second part of the work, the study of PP-Fe(III)Cit mixtures in aqueous solution was undertaken in the absence and presence of light. Indeed, in the dark, the three substrates showed no interaction with Fe(III)Cit complex in aqueous solution when the mixture ages at room temperature. Under irradiation, the photodegradation of substrates induced by Fe(III)Cit complex, followed by spectrophotometry and HPLC, shows rapid kinetics in the beginning of reaction and then slowed down during the irradiation. This reaction appears to be dependent on several parameters such as pH, substrate and complex concentration. The Fe(II) and the hydrogen peroxide resulting from the photolysis of the complex have been quantified and highlight the involvement of the Fenton reaction in the oxidation process of PP. The mechanistic study reveals that hydroxyl radicals are involved in the photocatalytic process and this whatever the substrate used. The identification of the reaction intermediates by LC-MS made it possible to establish a degradation mechanism for each substrate. The following of the mineralization shows that the life of intermediates reaction is much greater than the starting product. To activate the photocatalytic process, the addition of hydrogen peroxide in the mixture DCFFe(III)Cit improves significantly the rate of disappearance of the substrate. To get closer to the environmental conditions, the effect of main elements present naturally in the aquatic ecosystem such as humic substances, bicarbonates and metals was examined and shows the need to take into account the impact of these elements. In order to verify the feasibility of the photochemical process in the environment, the same systems were studied under solar irradiation. The results show that such systems operate with higher kinetics as those observed in artificial irradiations..
Note de contenu : Annexe. Diplôme : Doctorat En ligne : ../theses/chimie/GHO7668.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11502 Photodegradation des produits pharmaceutiques induite par les complexes organiques de Fer(III) en solution aqueuse. [texte imprimé] / Imane Ghoul, Auteur ; Nadra Debbache, Directeur de thèse . - 15-janv-20 . - جامعة الإخوة منتوري قسنطينة, 2020 . - 226 f. ; 30 cm.
Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Chimie: Chimie Analytique et Environnement Diclofénac Aspirine Carbamazépine Fe(III)Cit Fenton photolyse Diclofenac Aspirin Photolysis ديكلوفيناك الأسبرين كاربامازيبين التحلل الضوئي Index. décimale : 540 Chimie et sciences connexes Résumé :
This work is a contribution to the photodegradation of three pharmaceutical compounds:
diclofenac (DCF), aspirin (ASP) and carbamazepine (CBZ) induced by organic complex of Fe(III) (Fe(III)Cit) in homogeneous phase under simulated and sunlight. A first part was devoted to the synthesis and characterization of Fe(III)Cit complex, which confirms its stability, its stoichiometry, while the effect of light irradiation revealed its photolysis, which generated the HO• radical. This oxidizing species has shown its effectiveness in the elimination of PP. In the second part of the work, the study of PP-Fe(III)Cit mixtures in aqueous solution was undertaken in the absence and presence of light. Indeed, in the dark, the three substrates showed no interaction with Fe(III)Cit complex in aqueous solution when the mixture ages at room temperature. Under irradiation, the photodegradation of substrates induced by Fe(III)Cit complex, followed by spectrophotometry and HPLC, shows rapid kinetics in the beginning of reaction and then slowed down during the irradiation. This reaction appears to be dependent on several parameters such as pH, substrate and complex concentration. The Fe(II) and the hydrogen peroxide resulting from the photolysis of the complex have been quantified and highlight the involvement of the Fenton reaction in the oxidation process of PP. The mechanistic study reveals that hydroxyl radicals are involved in the photocatalytic process and this whatever the substrate used. The identification of the reaction intermediates by LC-MS made it possible to establish a degradation mechanism for each substrate. The following of the mineralization shows that the life of intermediates reaction is much greater than the starting product. To activate the photocatalytic process, the addition of hydrogen peroxide in the mixture DCFFe(III)Cit improves significantly the rate of disappearance of the substrate. To get closer to the environmental conditions, the effect of main elements present naturally in the aquatic ecosystem such as humic substances, bicarbonates and metals was examined and shows the need to take into account the impact of these elements. In order to verify the feasibility of the photochemical process in the environment, the same systems were studied under solar irradiation. The results show that such systems operate with higher kinetics as those observed in artificial irradiations..
Note de contenu : Annexe. Diplôme : Doctorat En ligne : ../theses/chimie/GHO7668.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11502 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité GHO/7668 GHO/7668 Thèse Bibliothèque principale Thèses Disponible
Titre : Etude comparative de la photodégradation d’un colorant cationique et d’un colorant anionique en phase homogène et hétérogène : Modélisation des cinétiques à l’aide des plans d’expériences Type de document : texte imprimé Auteurs : Nassima Laid, Auteur ; Razika Zouaghi, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2017 Importance : 216 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : dye adsorption photolysis photocatalysis TiO2 experimental design colorant photolyse photocatalyse plan d’expérience Index. décimale : 540 Chimie et sciences connexes Résumé : Industrial effluents resulting from the textile, tannery or the printing activities present a
major source of coloring pollutant which is difficult to biodegrade. In this context, the
removal of two model dyes, an anionic dye of the xanthene family (Eosin Yellow), and a
cationic dye of the triphenylmethane family (Malachite Green) by the photochemical process
in homogeneous medium under irradiation (UV-C) at 254 nm and by the photocatalytic
process in a heterogeneous medium at 365 nm (UV-A/TiO2), was studied. The main objective
of this study is to evaluate the effectiveness of these processes in degrading target pollutants
at different operating conditions and to compare and determine the effect of the ionic charge
and the molecular structure of the compound to be degraded on the effectiveness of its
degradation.
The first part of this study focused on the removal of Malachite Green and Eosin Yellow in a
homogeneous medium by direct photochemistry at 254 nm and by the UV/H2O2 processes.
The results showed that the two dyes are photodegradable compounds in presence of UV
irradiation at 254 nm, in particular in the case of Eosin Yellow. However, the COD values
show a relatively low mineralization rate. The effect of certain parameters on the rat of
discoloration of the two dyes by direct photochemistry was studied (pH, intensity of the
photonic flux and the concentration of the dye). The photochemical reaction was significantly
improved in the presence of hydrogen peroxide (UV/H2O2 process) with an optimum
concentration of H2O2 at 10-2 mol L-1. Modeling of the effect of three parameters: dye
concentration, H2O2 concentration and photon flux on degradation rate of Malachite Green by
the process (UV/H2O2), showed that the concentration of H2O2 is the most determining factor
and that the interactions between the three parameters are not significant.
The second part of this study concerns the removal of Malachite Green and Eosin Yellow in a
heterogeneous medium by the UV/TiO2 processes. A kinetic study of the adsorption of the
two dyes studied shows that the mechanism of adsorption on TiO2-P25 is described by
kinetics of the pseudo-second order and that the adsorption isotherms of the dyes on the
catalyst are of type L (Langmuir). The photocatalytic process UV/TiO2 at 365 nm is found to
be very effective for the discoloration and mineralization of Malachite Green and Eosin
Yellow. Their degradation seems to follow the Langmuir-Hinshelwood mechanism and the
rate of their degradation is well described by pseudo-first order kinetics. A more important
discoloration and mineralization of the anionic dye (Eosin Yellow) compared to the cationic
dye (Malachite Green) is observed at natural pH. The operating parameters (the catalyst type
(P25, PC100, PC105, PC50, PC500), pH, dye concentration, temperature, photon flux,
catalyst concentration, presence of the anions (Cl−, HCO3−, SO42−, HPO4−, NO3−) and the
addition of H2O2) all influenced the degradation of Eosin Yellow and Malachite Green, but in
a different way. The use of sunlight as a source of energy in the process (UV/TiO2) has been
found to be very effective for the discoloration and mineralization of model compounds with
respect to UV light. In all experiments, photocatalytic degradation of both dyes was generally
found to correlate with adsorption on the surface of TiO2 in the dark. The application of the
experimental design methodology to model the influence of three experimental parameters
(catalyst particle size, catalyst concentration and pH of the solution) on the photocatalytic
process, showed that pH is the most determining factor and that all the interactions between
the three parameters studied are significant. The optimum values of the parameters giving
maximum yield were also determined.Diplôme : Doctorat en sciences En ligne : ../theses/chimie/LAI7104.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10497 Etude comparative de la photodégradation d’un colorant cationique et d’un colorant anionique en phase homogène et hétérogène : Modélisation des cinétiques à l’aide des plans d’expériences [texte imprimé] / Nassima Laid, Auteur ; Razika Zouaghi, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2017 . - 216 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : dye adsorption photolysis photocatalysis TiO2 experimental design colorant photolyse photocatalyse plan d’expérience Index. décimale : 540 Chimie et sciences connexes Résumé : Industrial effluents resulting from the textile, tannery or the printing activities present a
major source of coloring pollutant which is difficult to biodegrade. In this context, the
removal of two model dyes, an anionic dye of the xanthene family (Eosin Yellow), and a
cationic dye of the triphenylmethane family (Malachite Green) by the photochemical process
in homogeneous medium under irradiation (UV-C) at 254 nm and by the photocatalytic
process in a heterogeneous medium at 365 nm (UV-A/TiO2), was studied. The main objective
of this study is to evaluate the effectiveness of these processes in degrading target pollutants
at different operating conditions and to compare and determine the effect of the ionic charge
and the molecular structure of the compound to be degraded on the effectiveness of its
degradation.
The first part of this study focused on the removal of Malachite Green and Eosin Yellow in a
homogeneous medium by direct photochemistry at 254 nm and by the UV/H2O2 processes.
The results showed that the two dyes are photodegradable compounds in presence of UV
irradiation at 254 nm, in particular in the case of Eosin Yellow. However, the COD values
show a relatively low mineralization rate. The effect of certain parameters on the rat of
discoloration of the two dyes by direct photochemistry was studied (pH, intensity of the
photonic flux and the concentration of the dye). The photochemical reaction was significantly
improved in the presence of hydrogen peroxide (UV/H2O2 process) with an optimum
concentration of H2O2 at 10-2 mol L-1. Modeling of the effect of three parameters: dye
concentration, H2O2 concentration and photon flux on degradation rate of Malachite Green by
the process (UV/H2O2), showed that the concentration of H2O2 is the most determining factor
and that the interactions between the three parameters are not significant.
The second part of this study concerns the removal of Malachite Green and Eosin Yellow in a
heterogeneous medium by the UV/TiO2 processes. A kinetic study of the adsorption of the
two dyes studied shows that the mechanism of adsorption on TiO2-P25 is described by
kinetics of the pseudo-second order and that the adsorption isotherms of the dyes on the
catalyst are of type L (Langmuir). The photocatalytic process UV/TiO2 at 365 nm is found to
be very effective for the discoloration and mineralization of Malachite Green and Eosin
Yellow. Their degradation seems to follow the Langmuir-Hinshelwood mechanism and the
rate of their degradation is well described by pseudo-first order kinetics. A more important
discoloration and mineralization of the anionic dye (Eosin Yellow) compared to the cationic
dye (Malachite Green) is observed at natural pH. The operating parameters (the catalyst type
(P25, PC100, PC105, PC50, PC500), pH, dye concentration, temperature, photon flux,
catalyst concentration, presence of the anions (Cl−, HCO3−, SO42−, HPO4−, NO3−) and the
addition of H2O2) all influenced the degradation of Eosin Yellow and Malachite Green, but in
a different way. The use of sunlight as a source of energy in the process (UV/TiO2) has been
found to be very effective for the discoloration and mineralization of model compounds with
respect to UV light. In all experiments, photocatalytic degradation of both dyes was generally
found to correlate with adsorption on the surface of TiO2 in the dark. The application of the
experimental design methodology to model the influence of three experimental parameters
(catalyst particle size, catalyst concentration and pH of the solution) on the photocatalytic
process, showed that pH is the most determining factor and that all the interactions between
the three parameters studied are significant. The optimum values of the parameters giving
maximum yield were also determined.Diplôme : Doctorat en sciences En ligne : ../theses/chimie/LAI7104.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10497 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité LAI/7104 LAI/7104 Thèse Bibliothèque principale Thèses Disponible
