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Titre : Degradation des dimethylphenols (XYLENOLS) par des chromophores photoinducteurs en solution aqueuse Type de document : texte imprimé Auteurs : Sihem Belaidi, Auteur ; T. Sehili, Directeur de thèse Editeur : Constantine : Université Mentouri Constantine Année de publication : 2015 Importance : 194 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Chimie analytique physique et environnement Fenton photo-Fenton oxyde de fer naturel complexes Fe(III) – oxalate acide
oxalique DCO irradiation solaire natural iron oxide oxalic acid complex Fe (III) - oxalate COD sunlight فانتون فانتون الضوئي أكسید الحدید الطبیعي حمض الأكسالیك معقد (الحدید
(III) – الأكسالات) DCO الإشعاع الشمسيIndex. décimale : 540 Chimie et sciences connexes Résumé : In this study we have used dimethylphenols (xylenol) as models pollutants to show the effectiveness of the natural hematite (Fe2O3 natural) on the photocatalytic processes in heterogeneous environment.
The degradation of 3,5-dimethylphenol by Fenton and photo-Fenton processes was investigated, starting with the study of its photolysis at 254 nm and by H2O2/UV process.
Different physico-chemical parameters (concentrations of H2O2, Fe2+ and the pH) were tested in order to optimize the efficiency of Fenton process for degradation of 3,5-DMP. A Comparison of the performance of mineralization by different processes studied (Fenton and photo-Fenton) has shown that 70% and 80% of DOC removal was obtained after only 4 hours of photo-Fenton process at 365 nm and 254 nm respectively.
In the field of heterogeneous photocatalysis, a naturally occurring mineral was used. It was characterized by XRD, BET, IR and SEM. The XRD analysis showed the presence of 9 characteristic peaks attributed to hematite. Its photocatalytic efficiency was tested by the oxidation of 2,6-dimethylphenol (2,6-DMP). Photocatalysts based on iron (Fe2O3) have photocatalytic efficiency in the visible region. The results showed good efficiency under solar irradiation for the degradation of 2,6-DMP. Experiments carried at 365 nm required activation of the iron oxide with carboxylic acids. oxalic acid was the most effective carboxylic acid in terms of dissolution of natural iron oxide, and degradation of 2,6-DMP. Fe (III) - oxalate complex produce Fe2+ species by the photo-reduction of Fe3+ species and also lead to the
formation of hydrogen peroxide which reacts with Fe2+ to give •OH (Fenton reaction). We have optimized the experimental parameters affecting the degradation rate (oxalic acid concentration, pH, O2, temperature, inorganic ions ...) and propose a mechanism of degradation. The abatement rate of COD was 85% obtained for a treatment time of 14 hours in natural iron oxide - oxalate system under irradiation at 365 nm, demonstrating the ability of this technique to clean up effluents loaded with organic matter. The coupling of the system with the solar light has increased the rate of degradation of 2,6-DMP to 92% after 5 hours.
The use of natural iron oxide alone or in the presence of oxalic acid seems to be favored under solar irradiation which can reduce energy costs, especially in a country like Algeria.
Diplôme : Doctorat en sciences En ligne : ../theses/chimie/BEL6735.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9888 Degradation des dimethylphenols (XYLENOLS) par des chromophores photoinducteurs en solution aqueuse [texte imprimé] / Sihem Belaidi, Auteur ; T. Sehili, Directeur de thèse . - Constantine : Université Mentouri Constantine, 2015 . - 194 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Chimie analytique physique et environnement Fenton photo-Fenton oxyde de fer naturel complexes Fe(III) – oxalate acide
oxalique DCO irradiation solaire natural iron oxide oxalic acid complex Fe (III) - oxalate COD sunlight فانتون فانتون الضوئي أكسید الحدید الطبیعي حمض الأكسالیك معقد (الحدید
(III) – الأكسالات) DCO الإشعاع الشمسيIndex. décimale : 540 Chimie et sciences connexes Résumé : In this study we have used dimethylphenols (xylenol) as models pollutants to show the effectiveness of the natural hematite (Fe2O3 natural) on the photocatalytic processes in heterogeneous environment.
The degradation of 3,5-dimethylphenol by Fenton and photo-Fenton processes was investigated, starting with the study of its photolysis at 254 nm and by H2O2/UV process.
Different physico-chemical parameters (concentrations of H2O2, Fe2+ and the pH) were tested in order to optimize the efficiency of Fenton process for degradation of 3,5-DMP. A Comparison of the performance of mineralization by different processes studied (Fenton and photo-Fenton) has shown that 70% and 80% of DOC removal was obtained after only 4 hours of photo-Fenton process at 365 nm and 254 nm respectively.
In the field of heterogeneous photocatalysis, a naturally occurring mineral was used. It was characterized by XRD, BET, IR and SEM. The XRD analysis showed the presence of 9 characteristic peaks attributed to hematite. Its photocatalytic efficiency was tested by the oxidation of 2,6-dimethylphenol (2,6-DMP). Photocatalysts based on iron (Fe2O3) have photocatalytic efficiency in the visible region. The results showed good efficiency under solar irradiation for the degradation of 2,6-DMP. Experiments carried at 365 nm required activation of the iron oxide with carboxylic acids. oxalic acid was the most effective carboxylic acid in terms of dissolution of natural iron oxide, and degradation of 2,6-DMP. Fe (III) - oxalate complex produce Fe2+ species by the photo-reduction of Fe3+ species and also lead to the
formation of hydrogen peroxide which reacts with Fe2+ to give •OH (Fenton reaction). We have optimized the experimental parameters affecting the degradation rate (oxalic acid concentration, pH, O2, temperature, inorganic ions ...) and propose a mechanism of degradation. The abatement rate of COD was 85% obtained for a treatment time of 14 hours in natural iron oxide - oxalate system under irradiation at 365 nm, demonstrating the ability of this technique to clean up effluents loaded with organic matter. The coupling of the system with the solar light has increased the rate of degradation of 2,6-DMP to 92% after 5 hours.
The use of natural iron oxide alone or in the presence of oxalic acid seems to be favored under solar irradiation which can reduce energy costs, especially in a country like Algeria.
Diplôme : Doctorat en sciences En ligne : ../theses/chimie/BEL6735.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9888 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BEL/6735 BEL/6735 Thèse Bibliothèque principale Thèses Disponible
Titre : Efficacite photocatalytique des oxydes de fer (hematite) et des acides carboxyliques sur la degradation de derives phenoliques chlores en solution aqueuse Type de document : texte imprimé Auteurs : Wassila Remache, Auteur ; Tahar Sehili, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 168 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : 2,4-dichlorophénol Photo-Fenton hétérogène Oxyde de fer naturel Fe(III) – carboxylate Acide oxalique Irradiation solaire Solution aqueuse Heterogeneous photo-Fenton Natural iron oxide Oxalic acid Solar radiation ثنائي الكلوروفینول أكسید الحدید الطبیعي الحدید ) -(IIIأكسالات حمض الأكسالیك الإشعاع
الشمسىIndex. décimale : 540 Chimie et sciences connexes Résumé : The degradation of 2,4-DCP photoinduced by natural iron oxide was studied in aqueous suspension up on irradiation at 365 nm and by solar light. The effects of various factors, such as photolysis, adsorption, effect of pH, temperature, wavelength and the degradation pathways were investigated.
The UV light has no considerable influence on the catalytic activity of the NIO, it is very important to note that there is a strong overlap between the absorption spectrum of NIO and the solar emission spectrum of the sun leading the capacity of this oxide to photoinduce the degradation of 2,4-DCP under solar light. 2,4-DCP was nearly completely removed in about 6 h.
The second part of the work of this thesis has demonstrated the significant impact that could have sunlight on the activation of iron-carboxylate complexes in the degradation of 2,4-DCP.
The complex iron-oxalate was found the most photocative for the degradation of 2,4-DCP in both systems (UV and solar irradiation). Photochemical behavior of iron released into solution, mostly influenced by pH, will monitor the effectiveness of the reaction disappearance of the pollutant.
Our results showed that photocatalysis in the iron-oxalate system is an effective technique for the degradation of 2,4-DCP where seven major by-products were identified and that this degradation mainly through hydroxyle radicals •OH. Mineralization of 2,4-DCP was achieved in 11h in our experimental conditions.
Furthermore, in the heterogeneous iron oxide /H2O2 system the method is effective only at acidic conditions and the disappearance of 2,4-DCP is strongly dependent on the concentration of H2O2 , substrate and catalyst dose. The photodegradation of 2,4-DCP can be directly attributed to the attack of •OH radicals. 2,4-DCP is totally degraded that after formation of various by-products can be completely mineralized to H2O, Cl- et CO2.
Our work shows that the activation of natural iron oxide by carboxylic acids and hydrogen peroxide could have a considerable impact on the fate of organic pollutants in aquatic environment.
Diplôme : Doctorat en sciences En ligne : ../theses/chimie/REM7256.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10854 Efficacite photocatalytique des oxydes de fer (hematite) et des acides carboxyliques sur la degradation de derives phenoliques chlores en solution aqueuse [texte imprimé] / Wassila Remache, Auteur ; Tahar Sehili, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 168 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : 2,4-dichlorophénol Photo-Fenton hétérogène Oxyde de fer naturel Fe(III) – carboxylate Acide oxalique Irradiation solaire Solution aqueuse Heterogeneous photo-Fenton Natural iron oxide Oxalic acid Solar radiation ثنائي الكلوروفینول أكسید الحدید الطبیعي الحدید ) -(IIIأكسالات حمض الأكسالیك الإشعاع
الشمسىIndex. décimale : 540 Chimie et sciences connexes Résumé : The degradation of 2,4-DCP photoinduced by natural iron oxide was studied in aqueous suspension up on irradiation at 365 nm and by solar light. The effects of various factors, such as photolysis, adsorption, effect of pH, temperature, wavelength and the degradation pathways were investigated.
The UV light has no considerable influence on the catalytic activity of the NIO, it is very important to note that there is a strong overlap between the absorption spectrum of NIO and the solar emission spectrum of the sun leading the capacity of this oxide to photoinduce the degradation of 2,4-DCP under solar light. 2,4-DCP was nearly completely removed in about 6 h.
The second part of the work of this thesis has demonstrated the significant impact that could have sunlight on the activation of iron-carboxylate complexes in the degradation of 2,4-DCP.
The complex iron-oxalate was found the most photocative for the degradation of 2,4-DCP in both systems (UV and solar irradiation). Photochemical behavior of iron released into solution, mostly influenced by pH, will monitor the effectiveness of the reaction disappearance of the pollutant.
Our results showed that photocatalysis in the iron-oxalate system is an effective technique for the degradation of 2,4-DCP where seven major by-products were identified and that this degradation mainly through hydroxyle radicals •OH. Mineralization of 2,4-DCP was achieved in 11h in our experimental conditions.
Furthermore, in the heterogeneous iron oxide /H2O2 system the method is effective only at acidic conditions and the disappearance of 2,4-DCP is strongly dependent on the concentration of H2O2 , substrate and catalyst dose. The photodegradation of 2,4-DCP can be directly attributed to the attack of •OH radicals. 2,4-DCP is totally degraded that after formation of various by-products can be completely mineralized to H2O, Cl- et CO2.
Our work shows that the activation of natural iron oxide by carboxylic acids and hydrogen peroxide could have a considerable impact on the fate of organic pollutants in aquatic environment.
Diplôme : Doctorat en sciences En ligne : ../theses/chimie/REM7256.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10854 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité REM/7256 REM/7256 Thèse Bibliothèque principale Thèses Disponible
