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Partager le résultat de cette recherche Interroger des sources externesPhototransformation de l’acide 5-chlorosalicylique en solution aqueuse et sur cuticule foliaire simulee. / Radia Tafer
Titre : Phototransformation de l’acide 5-chlorosalicylique en solution aqueuse et sur cuticule foliaire simulee. Type de document : texte imprimé Auteurs : Radia Tafer, Auteur ; Abdelaziz Boulkamh, Directeur de thèse ; Claire Richard, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 201 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Chimie: chimie analytique, physique et environnement Phototransformation acide 5-chlorosalicylique éliciteur triplet radicaux hydroxyle 5-chlorosalicylic acid elicitor hydroxyl radicals تحول ضوئي حمض -5كلورو ساليسيليك محفز الدفاع الذاتي للنبات الفئة الثلاثية جذور الهيدروكسيل Index. décimale : 540 Chimie et sciences connexes Résumé :
The photochemical reactivity of 5-chlorosalicylic acid (Cl-C6H3-OH,COOH; 5-ClSA), an elicitor of natural plant defense mechanisms, was examined under different experimental conditions. In neutral aqueous solution and under the action of a simulated solar irradiation (suntest), the monoanionic form (5-ClSA‒) is phototransformed relatively quickly, dechlorination being the predominant primary step. This leads mainly to the respective conjugated bases of 2,5- dihydroxybenzoic acid (DHBA, P3), by photohydrolysis, and 2-carboxy-3-hydroxy-1,4- benzoquinone (P1), by photooxidation. A hydroxylation compound of 5-ClSA‒ (5ClSA-OH) and several dimeric compounds are also formed, but in smaller proportions. The phototransformation of DHBA, experimented separately, leads to the formation of dihydroxycyclopentadiene acid, through a very exceptional ring-contraction reaction. By fusion with P1, DHBA generates a polysubstituted biphenyl and by molecular association with the same P1, a quinhydrone-like complex, via an intermolecular charge transfer, a phenomenon that is just as rarely observed as the contraction of the cycle. About 40 photoproducts, comprising from 19 to 01 C atoms (formaldehyde), diversely oxygenated, comprising aromatic, aliphatic, polycyclic, monocyclic or acyclic compounds, in trace or ultra-trace concentrations, have been identified, revealing the nature of the detectable successive photoproducts, up to quasi-mineralization. The latter was confirmed by measuring the residual content of Total Organic Carbon. The production and involvement of hydroxy radicals (OH•), produced by ""light-induced secondary OH precursors "", in the mineralization of 5-ClSA, has been experimentally proven. The mechanism of photolysis of 5-ClSA, established through the identification of its photoproducts, has been refined by the identification of transient species, at the top of which is the triplet of 5-ClSA, a fleeting species holding nevertheless a central role. The solvated electron, the 2-carboxy-4-chlorophenoxyl radical and the carbene ""4-oxocyclohexa-2,5- dienylidene"" complete the picture. Singlet oxygen (1O2), the corollary of the triplet, was evidenced by phosphorescence. On a leaf model, 5-ClSA, without additives, resists to phototransformation. The presence of a surfactant, added in commercial formulations, considerably accelerates the phototransformation, while orienting it towards reduction. Salicylic acid (SA), the only photoproduct that accumulates, is also a mediator in the response of plants to pathogens.Note de contenu :
Annexes.Diplôme : Doctorat en sciences En ligne : ../theses/chimie/TAF7533.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11372 Phototransformation de l’acide 5-chlorosalicylique en solution aqueuse et sur cuticule foliaire simulee. [texte imprimé] / Radia Tafer, Auteur ; Abdelaziz Boulkamh, Directeur de thèse ; Claire Richard, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2019 . - 201 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Chimie: chimie analytique, physique et environnement Phototransformation acide 5-chlorosalicylique éliciteur triplet radicaux hydroxyle 5-chlorosalicylic acid elicitor hydroxyl radicals تحول ضوئي حمض -5كلورو ساليسيليك محفز الدفاع الذاتي للنبات الفئة الثلاثية جذور الهيدروكسيل Index. décimale : 540 Chimie et sciences connexes Résumé :
The photochemical reactivity of 5-chlorosalicylic acid (Cl-C6H3-OH,COOH; 5-ClSA), an elicitor of natural plant defense mechanisms, was examined under different experimental conditions. In neutral aqueous solution and under the action of a simulated solar irradiation (suntest), the monoanionic form (5-ClSA‒) is phototransformed relatively quickly, dechlorination being the predominant primary step. This leads mainly to the respective conjugated bases of 2,5- dihydroxybenzoic acid (DHBA, P3), by photohydrolysis, and 2-carboxy-3-hydroxy-1,4- benzoquinone (P1), by photooxidation. A hydroxylation compound of 5-ClSA‒ (5ClSA-OH) and several dimeric compounds are also formed, but in smaller proportions. The phototransformation of DHBA, experimented separately, leads to the formation of dihydroxycyclopentadiene acid, through a very exceptional ring-contraction reaction. By fusion with P1, DHBA generates a polysubstituted biphenyl and by molecular association with the same P1, a quinhydrone-like complex, via an intermolecular charge transfer, a phenomenon that is just as rarely observed as the contraction of the cycle. About 40 photoproducts, comprising from 19 to 01 C atoms (formaldehyde), diversely oxygenated, comprising aromatic, aliphatic, polycyclic, monocyclic or acyclic compounds, in trace or ultra-trace concentrations, have been identified, revealing the nature of the detectable successive photoproducts, up to quasi-mineralization. The latter was confirmed by measuring the residual content of Total Organic Carbon. The production and involvement of hydroxy radicals (OH•), produced by ""light-induced secondary OH precursors "", in the mineralization of 5-ClSA, has been experimentally proven. The mechanism of photolysis of 5-ClSA, established through the identification of its photoproducts, has been refined by the identification of transient species, at the top of which is the triplet of 5-ClSA, a fleeting species holding nevertheless a central role. The solvated electron, the 2-carboxy-4-chlorophenoxyl radical and the carbene ""4-oxocyclohexa-2,5- dienylidene"" complete the picture. Singlet oxygen (1O2), the corollary of the triplet, was evidenced by phosphorescence. On a leaf model, 5-ClSA, without additives, resists to phototransformation. The presence of a surfactant, added in commercial formulations, considerably accelerates the phototransformation, while orienting it towards reduction. Salicylic acid (SA), the only photoproduct that accumulates, is also a mediator in the response of plants to pathogens.Note de contenu :
Annexes.Diplôme : Doctorat en sciences En ligne : ../theses/chimie/TAF7533.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11372 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité TAF/7533 TAF/7533 Thèse Bibliothèque principale Thèses Disponible
Titre : Comportements thermique et photochimique du paracétamol et de l’aspirine par la goethite en solution aqueuse en phase hétérogène Type de document : texte imprimé Auteurs : Yazid Mameri, Auteur ; Nadra Debbache, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 177 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Paracétamol Aspirine Photodégradation Radicaux hydroxyle Goethite Fenton Paracetamol Aspirin Photodegradation Hydroxyl radicals الباراسيتامول الأسبرين التفكك الضوئي جذور الهيدروكسيل فانتون Index. décimale : 540 Chimie et sciences connexes Résumé : The photodegradation of two pharmaceuticals (PP), paracetamol (PC) and aspirin (ASP), induced by an iron (III) oxyhydroxide (Goethite) was studied in aqueous solution in heterogeneous phase. The phototransformation of the substrates was followed by spectrophotometry and HPLC in various mixtures namely: PP-Goethite, PP-Goethite-H2O2 and PP-Goethite-carboxylic acid. In absence of light both substrates showed different behavior with regard to Goethite in aqueous solution. Indeed, no interaction was observed in the case of the PC whereas a particular reaction was highlighted in the case of the ASP. Under irradiation, photodegradation of PP induced by Goethite shows slow kinetics and is dependent on several parameters such as pH, substrate concentration and catalyst. Fe (II) formed exclusively in the ASP-Goethite mixture shows the photocatalytic dissolution of Goethite. The mechanistic study reveals that hydroxyl radicals are not involved in the photocatalytic process of PC, however they govern on the photodegradation mechanism of ASP. The addition of hydrogen peroxide in the PP-Goethite mixture improves significantly the rate of disappearance of the substrates following a large production of ●OH radicals generated by a heterogeneous photo Fenton reaction. Different parameters have been studied, the effect of pH, as well as the concentration of H2O2.
The addition of carboxylic acid to the PP-Goethite system has also been studied and shows that oxalic acid has the most important photoactivity following the involvement of the eterogeneous like-Fenton process resulting from the photoreductive dissolution of the complex surface formed between Fe (III) of Goethite and oxalic acid. The following of the mineralization shows that the life of intermediates reaction is much greater than the starting product. 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 kinetics of the same order as those observed in artificial irradiations. These results provide some knowledge about the fate of PP in the aquatic environment as well as the photocatalytic treatment with oxy (hydroxides) of Fe (III). These results are very promising for the application of this system under pH conditions close to those met in the environment.
Diplôme : Doctorat en sciences En ligne : ../theses/chimie/MAM7351.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11001 Comportements thermique et photochimique du paracétamol et de l’aspirine par la goethite en solution aqueuse en phase hétérogène [texte imprimé] / Yazid Mameri, Auteur ; Nadra Debbache, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 177 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Paracétamol Aspirine Photodégradation Radicaux hydroxyle Goethite Fenton Paracetamol Aspirin Photodegradation Hydroxyl radicals الباراسيتامول الأسبرين التفكك الضوئي جذور الهيدروكسيل فانتون Index. décimale : 540 Chimie et sciences connexes Résumé : The photodegradation of two pharmaceuticals (PP), paracetamol (PC) and aspirin (ASP), induced by an iron (III) oxyhydroxide (Goethite) was studied in aqueous solution in heterogeneous phase. The phototransformation of the substrates was followed by spectrophotometry and HPLC in various mixtures namely: PP-Goethite, PP-Goethite-H2O2 and PP-Goethite-carboxylic acid. In absence of light both substrates showed different behavior with regard to Goethite in aqueous solution. Indeed, no interaction was observed in the case of the PC whereas a particular reaction was highlighted in the case of the ASP. Under irradiation, photodegradation of PP induced by Goethite shows slow kinetics and is dependent on several parameters such as pH, substrate concentration and catalyst. Fe (II) formed exclusively in the ASP-Goethite mixture shows the photocatalytic dissolution of Goethite. The mechanistic study reveals that hydroxyl radicals are not involved in the photocatalytic process of PC, however they govern on the photodegradation mechanism of ASP. The addition of hydrogen peroxide in the PP-Goethite mixture improves significantly the rate of disappearance of the substrates following a large production of ●OH radicals generated by a heterogeneous photo Fenton reaction. Different parameters have been studied, the effect of pH, as well as the concentration of H2O2.
The addition of carboxylic acid to the PP-Goethite system has also been studied and shows that oxalic acid has the most important photoactivity following the involvement of the eterogeneous like-Fenton process resulting from the photoreductive dissolution of the complex surface formed between Fe (III) of Goethite and oxalic acid. The following of the mineralization shows that the life of intermediates reaction is much greater than the starting product. 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 kinetics of the same order as those observed in artificial irradiations. These results provide some knowledge about the fate of PP in the aquatic environment as well as the photocatalytic treatment with oxy (hydroxides) of Fe (III). These results are very promising for the application of this system under pH conditions close to those met in the environment.
Diplôme : Doctorat en sciences En ligne : ../theses/chimie/MAM7351.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11001 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité MAM/7351 MAM/7351 Thèse Bibliothèque principale Thèses Disponible
Titre : Dégradation photocatalytique de polluant pharmaceutique en présence des acides organiques et des métaux de transitions en solution aqueuse. Type de document : texte imprimé Auteurs : Mohamed El Hadi Benssassi, Auteur ; Tahar Sehili, Directeur de thèse Mention d'édition : 04-juil-21 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2021 Importance : 179 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Chime: Chimie Analytique et Environnement Paracétamol Photodégradation FeIII-Aspartate FeIII-Glutamate FeIII-Lactate Radicaux hydroxyle Paracetamol Photodegradation hydroxyl radicals الباراسيتامول التحلل الضوئي الجذور الهيدروكسيلية FeIII-Asp FeIII-Glu FeIII-Lac Index. décimale : 540 Chimie et sciences connexes Résumé :
The objective of this work is to study the photochemical fate of paracetamol or acetaminophen (PC) as a model pharmaceutical pollutant, in the presence of three iron complexes (FeIII-Aspartate, FeIII-Glutamate, or FeIII-Lactate) under irradiation at 365 nm. First, the FeIII complexes were characterized by UV-visible spectrophotometry; the results confirmed that these complexes are stable in the dark and at room temperature. Under irradiation at 365 nm, the photolysis of these complexes is relatively rapid: about 71% of the FeIII-Aspartate complex (t1/2 = 10.5 min, pH = 3.0) decomposed after 1 hour of irradiation, and about 73% (t½ = 6.2 min, pH = 3.40), and 91% (t½ = 6.4 min, pH = 3.0) in the case of the FeIII-Glutamate and FeIII-Lactate complex, respectively. In addition, this photochemical transformation depends on the wavelength of irradiation and pH. Direct photolysis of paracetamol under UVA irradiation showed a negligible effect, while the presence of FeIIIcomplexes favors the photodegradation of PC, which is faster in the presence of the FeIII-Lactate complex. Photodegradation was studied using various parameters such as initial pH, complex concentration, oxygen, and paracetamol concentration. The addition of T-BuOH as a hydroxyl radical scavenger and anaerobic conditions inhibit the photodegradation of PC, indicating that the photodegradation of paracetamol in the presence of FeIII-Asp, FeIII-Glu, or FeIII-Lact complexes is limited by the formation of hydrogen peroxide, the source of HO●. Seven transformation by-products have been identified by HPLC-MS, mainly hydroxylated derivatives. Reaction pathways are identified, highlighting the role of long-lived photoformed radicals. This study highlights the important role that organic iron complexes can play on the fate of pharmaceutical pollutants in the environment aquatic.
Diplôme : Doctorat En ligne : ../theses/chimie/BEN7775.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11609 Dégradation photocatalytique de polluant pharmaceutique en présence des acides organiques et des métaux de transitions en solution aqueuse. [texte imprimé] / Mohamed El Hadi Benssassi, Auteur ; Tahar Sehili, Directeur de thèse . - 04-juil-21 . - جامعة الإخوة منتوري قسنطينة, 2021 . - 179 f. ; 30 cm.
Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Chime: Chimie Analytique et Environnement Paracétamol Photodégradation FeIII-Aspartate FeIII-Glutamate FeIII-Lactate Radicaux hydroxyle Paracetamol Photodegradation hydroxyl radicals الباراسيتامول التحلل الضوئي الجذور الهيدروكسيلية FeIII-Asp FeIII-Glu FeIII-Lac Index. décimale : 540 Chimie et sciences connexes Résumé :
The objective of this work is to study the photochemical fate of paracetamol or acetaminophen (PC) as a model pharmaceutical pollutant, in the presence of three iron complexes (FeIII-Aspartate, FeIII-Glutamate, or FeIII-Lactate) under irradiation at 365 nm. First, the FeIII complexes were characterized by UV-visible spectrophotometry; the results confirmed that these complexes are stable in the dark and at room temperature. Under irradiation at 365 nm, the photolysis of these complexes is relatively rapid: about 71% of the FeIII-Aspartate complex (t1/2 = 10.5 min, pH = 3.0) decomposed after 1 hour of irradiation, and about 73% (t½ = 6.2 min, pH = 3.40), and 91% (t½ = 6.4 min, pH = 3.0) in the case of the FeIII-Glutamate and FeIII-Lactate complex, respectively. In addition, this photochemical transformation depends on the wavelength of irradiation and pH. Direct photolysis of paracetamol under UVA irradiation showed a negligible effect, while the presence of FeIIIcomplexes favors the photodegradation of PC, which is faster in the presence of the FeIII-Lactate complex. Photodegradation was studied using various parameters such as initial pH, complex concentration, oxygen, and paracetamol concentration. The addition of T-BuOH as a hydroxyl radical scavenger and anaerobic conditions inhibit the photodegradation of PC, indicating that the photodegradation of paracetamol in the presence of FeIII-Asp, FeIII-Glu, or FeIII-Lact complexes is limited by the formation of hydrogen peroxide, the source of HO●. Seven transformation by-products have been identified by HPLC-MS, mainly hydroxylated derivatives. Reaction pathways are identified, highlighting the role of long-lived photoformed radicals. This study highlights the important role that organic iron complexes can play on the fate of pharmaceutical pollutants in the environment aquatic.
Diplôme : Doctorat En ligne : ../theses/chimie/BEN7775.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11609 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BEN/7775 BEN/7775 Thèse Bibliothèque principale Thèses Disponible
Titre : Comportement d’un oxyhydroxyde de Fe(III) vis-à-vis d’un produit pharmaceutique en solution aqueuse en présence de lumières naturelle et simulée. Type de document : texte imprimé Auteurs : Mohamed el Mehdi Benacherine, Auteur ; Nadra Debbache, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2017 Importance : 167 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Amoxicilline Photodégradation Radicaux hydroxyle Goethite Fenton Amoxicillin photodegradation hydroxyl radicals hydrogen peroxide oxalic acid أموكسیسیلین التفكك الضوئي الجذور الھیدروكسیلیة •OH فانتون الجیوثیت (GOE) (like Fenton) نوﺘﻧﺎﻔﻟﺎﺑ ﮫﯿﺒﺸﻟا Index. décimale : 540 Chimie et sciences connexes Résumé : Our objectives in this thesis were to demonstrate the effectiveness of Goethite (GOE) in the
amoxicillin (AMX) photodegradation process under artificial and solar irradiation by different
systems, as well as the optimization of experimental parameters affecting the rate of the
degradation. Different analytical methods have been used in the characterization of AMX and
GOE. In the absence of light, the transformation of AMX was studied in different mixtures
(AMX-GOE, AMX-GOE-H2O2 and AMX-GOE-Carboxylic Acid). An interaction between
AMX and GOE was demonstrated; H2O2 significantly improved the degradation of AMX
while no effect was mentioned in the case of the presence of carboxylic acids. Under
irradiation and in the absence of GOE, AMX was found to be photolysed at 254 nm and
refractory to photolysis at 365 nm (monochromatic and polychromatic); this is due to the
overlap between the absorption spectrum of AMX and the light source.
The photodegradation of AMX by heterogeneous photocatalysis in the presence of GOE has
been studied. Results show that the photodegradation is dependent on several parameters such
as pH, substrate and catalyst concentration. The use of free radical inhibitors has shown that
the reaction mechanism is dominated by •OH radicals where oxygen plays an important role.
The addition of H2O2 to the solution improves the degradation of AMX and increases its rate
of mineralization in terms of chemical oxygen demand. The degradation is effected by the
contribution of the •OH radicals and also by oxidation on the surface of GOE. The AMXGOE-carboxylic acid system has been tested, among the used acids, oxalic acid was the only
one that showed a photo-activity. By comparing the degradation kinetics of AMX in natural
and artificial light in the three studied systems, it is found that the degradation rate is higher
under solar irradiation.
Diplôme : Doctorat En ligne : ../theses/chimie/BEN7137.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10465 Comportement d’un oxyhydroxyde de Fe(III) vis-à-vis d’un produit pharmaceutique en solution aqueuse en présence de lumières naturelle et simulée. [texte imprimé] / Mohamed el Mehdi Benacherine, Auteur ; Nadra Debbache, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2017 . - 167 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Amoxicilline Photodégradation Radicaux hydroxyle Goethite Fenton Amoxicillin photodegradation hydroxyl radicals hydrogen peroxide oxalic acid أموكسیسیلین التفكك الضوئي الجذور الھیدروكسیلیة •OH فانتون الجیوثیت (GOE) (like Fenton) نوﺘﻧﺎﻔﻟﺎﺑ ﮫﯿﺒﺸﻟا Index. décimale : 540 Chimie et sciences connexes Résumé : Our objectives in this thesis were to demonstrate the effectiveness of Goethite (GOE) in the
amoxicillin (AMX) photodegradation process under artificial and solar irradiation by different
systems, as well as the optimization of experimental parameters affecting the rate of the
degradation. Different analytical methods have been used in the characterization of AMX and
GOE. In the absence of light, the transformation of AMX was studied in different mixtures
(AMX-GOE, AMX-GOE-H2O2 and AMX-GOE-Carboxylic Acid). An interaction between
AMX and GOE was demonstrated; H2O2 significantly improved the degradation of AMX
while no effect was mentioned in the case of the presence of carboxylic acids. Under
irradiation and in the absence of GOE, AMX was found to be photolysed at 254 nm and
refractory to photolysis at 365 nm (monochromatic and polychromatic); this is due to the
overlap between the absorption spectrum of AMX and the light source.
The photodegradation of AMX by heterogeneous photocatalysis in the presence of GOE has
been studied. Results show that the photodegradation is dependent on several parameters such
as pH, substrate and catalyst concentration. The use of free radical inhibitors has shown that
the reaction mechanism is dominated by •OH radicals where oxygen plays an important role.
The addition of H2O2 to the solution improves the degradation of AMX and increases its rate
of mineralization in terms of chemical oxygen demand. The degradation is effected by the
contribution of the •OH radicals and also by oxidation on the surface of GOE. The AMXGOE-carboxylic acid system has been tested, among the used acids, oxalic acid was the only
one that showed a photo-activity. By comparing the degradation kinetics of AMX in natural
and artificial light in the three studied systems, it is found that the degradation rate is higher
under solar irradiation.
Diplôme : Doctorat En ligne : ../theses/chimie/BEN7137.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10465 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BEN/7137 BEN/7137 Thèse Bibliothèque principale Thèses Disponible
Titre : Contribution à l’étude de la dégradation photochimique de polluants organiques par les oxyhydroxydes de Fe (III) en solution aqueuse en phase hétérogène. Type de document : texte imprimé Auteurs : Sara Belattar, Auteur ; Nadra Debbache, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 161 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Photodégradation La GOE Dérivés phénoliques Radicaux hydroxyle Fenton Photodegradation GOE Phenolic derivatives Hydroxyl radicals التحلل الضوئي GOمشتقات الفینول ، جذور الھیدروكسیل فنتون Index. décimale : 540 Chimie et sciences connexes Résumé : The effectiveness of Goethite (GOE) in inducing the photodegradation of organic pollutants under artificial and solar irradiation in a heterogeneous medium and in aqueous solution was the main objective of this study. We used four organic pollutants of the phenol family (RP, BBP, BCP, phenol) whose chemical structure differs depending on the substitute nature. In the absence of light and in our experimental conditions, two distinct behaviors were observed as a function of the pollutants studied during the mixing of the GOE-substrate. Indeed, in the Phenol-GOE mixture, no interaction was observed whereas a slow reaction, in the presence of the GOE, was demonstrated with RP, BBP and BCP. This interaction can be attributed to a low adsorption of the substrate on the GOE in the following order: BCP (15%)> BBP (12%)> RP (5%)> Phenol (1%), and this phenomenon is optimal in acidic medium. The addition of H2O2 accelerates the thermal process in RP-GOE system while an inhibitory effect was observed for the other two substrates (BBP, BCP) in the presence of GOE. The presence of carboxylic acids in the substrate-GOE system has shown that oxalic acid has a positive effect on the kinetics of BCP and RP eliminations under our experimental conditions. Under irradiation at 365 nm, the photodegradation of these pollutants by the GOE, was characterized by slow kinetics and seems to be dependent on several parameters such as the pH, the concentration of the substrate, the catalyst concentration, the oxygen and the molecular structure of the substrates. The mechanistic study reveals that the radicals HO • do not intervene in the mechanism of degradation of the phenol on the other hand they govern the reaction in the case of RP, BBP and BCP. The addition of H2O2 in a GOE suspension significantly improves the rate of photodegradation due to additional production of HO• radicals generated by the Fenton photo process. Different parameters have been studied to optimize this process. In the same way, the efficiency of the photochemical process is improved by the presence of carboxylic acid in a GOE suspension following the involvement of the heterogeneous like-Fenton process resulting from the reductive photo dissolution of the surface complex formed between the Fe (III) Goethite and oxalic acid. 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 kinetics of the same order as those observed in artificial irradiation, which can reduce the energy costs of the photochemical process.Diplôme : Doctorat en sciences En ligne : ../theses/chimie/BEL7350.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11000 Contribution à l’étude de la dégradation photochimique de polluants organiques par les oxyhydroxydes de Fe (III) en solution aqueuse en phase hétérogène. [texte imprimé] / Sara Belattar, Auteur ; Nadra Debbache, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 161 f. ; 30 cm.
2 copies imprimées disponibles
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ChimieTags : Photodégradation La GOE Dérivés phénoliques Radicaux hydroxyle Fenton Photodegradation GOE Phenolic derivatives Hydroxyl radicals التحلل الضوئي GOمشتقات الفینول ، جذور الھیدروكسیل فنتون Index. décimale : 540 Chimie et sciences connexes Résumé : The effectiveness of Goethite (GOE) in inducing the photodegradation of organic pollutants under artificial and solar irradiation in a heterogeneous medium and in aqueous solution was the main objective of this study. We used four organic pollutants of the phenol family (RP, BBP, BCP, phenol) whose chemical structure differs depending on the substitute nature. In the absence of light and in our experimental conditions, two distinct behaviors were observed as a function of the pollutants studied during the mixing of the GOE-substrate. Indeed, in the Phenol-GOE mixture, no interaction was observed whereas a slow reaction, in the presence of the GOE, was demonstrated with RP, BBP and BCP. This interaction can be attributed to a low adsorption of the substrate on the GOE in the following order: BCP (15%)> BBP (12%)> RP (5%)> Phenol (1%), and this phenomenon is optimal in acidic medium. The addition of H2O2 accelerates the thermal process in RP-GOE system while an inhibitory effect was observed for the other two substrates (BBP, BCP) in the presence of GOE. The presence of carboxylic acids in the substrate-GOE system has shown that oxalic acid has a positive effect on the kinetics of BCP and RP eliminations under our experimental conditions. Under irradiation at 365 nm, the photodegradation of these pollutants by the GOE, was characterized by slow kinetics and seems to be dependent on several parameters such as the pH, the concentration of the substrate, the catalyst concentration, the oxygen and the molecular structure of the substrates. The mechanistic study reveals that the radicals HO • do not intervene in the mechanism of degradation of the phenol on the other hand they govern the reaction in the case of RP, BBP and BCP. The addition of H2O2 in a GOE suspension significantly improves the rate of photodegradation due to additional production of HO• radicals generated by the Fenton photo process. Different parameters have been studied to optimize this process. In the same way, the efficiency of the photochemical process is improved by the presence of carboxylic acid in a GOE suspension following the involvement of the heterogeneous like-Fenton process resulting from the reductive photo dissolution of the surface complex formed between the Fe (III) Goethite and oxalic acid. 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 kinetics of the same order as those observed in artificial irradiation, which can reduce the energy costs of the photochemical process.Diplôme : Doctorat en sciences En ligne : ../theses/chimie/BEL7350.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11000 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BEL/7350 BEL/7350 Thèse Bibliothèque principale Thèses Disponible
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