title: Oxidative photodegradation of herbicide fenuron in aqueous solution by natural iron oxide α-Fe2O3, influence of polycarboxylic acids.
abstract: The photodegradation of the herbicide fenuron (1,1-dimethyl-3-phenylurea) by using a natural iron oxide (NIO), α-Fe2O3, in aqueous solution at acidic pH has been undertaken. The NIO was characterized by the Raman spectroscopy method. The degradation pathways and the formation of degradation products were studied. A high-pressure mercury lamp and sunlight were employed as light source. Fenuron photodegradation using NIO with oxalic acid followed the pseudo-first-order kinetics, the optimal experimental conditions were [oxalic acid]0 = 10(-3) M and [NIO] = 0.1 g L(-1) at pH 3. A UVA/NIO/oxalic acid system led to a low fenuron half-life (60 min). The results were even better when solar light is used (30 min). The variables studied were the doses of iron oxide, of carboxylic acids, the solution pH and the effect of sunlight irradiation. The effects of four carboxylic acids, oxalic, citric, tartaric and malic acids, on the fenuron photodegradation with NIO have been investigated, oxalic acid was the most effective carboxylic acid used at pH 3. A similar trend was observed for the removal of total organic carbon (TOC), 75% of TOC was removed. The analytical study showed many aromatic intermediates, short-chain carboxylic acids and inorganic ion.
authors.affiliation: a Laboratoire des Sciences et Technologies de l'Environnement (LSTE) , Faculté des Sciences Exactes, Université Constantine1 , 25000 Constantine , Algerie.|b Institut Européen des Membranes (IEM), UMR 5635 (CNRS-ENSCM-UM) , Université Montpellier , Place E. Bataillon, F-34095 Montpellier , France.
authors.forename: Mohamed El Amine
authors.initials: Mel A
authors.lastname: Kribéche
authors.affiliation: a Laboratoire des Sciences et Technologies de l'Environnement (LSTE) , Faculté des Sciences Exactes, Université Constantine1 , 25000 Constantine , Algerie.
authors.forename: Hind
authors.initials: H
authors.lastname: Mechakra
authors.affiliation: a Laboratoire des Sciences et Technologies de l'Environnement (LSTE) , Faculté des Sciences Exactes, Université Constantine1 , 25000 Constantine , Algerie.
authors.forename: Tahar
authors.initials: T
authors.lastname: Sehili
authors.affiliation: b Institut Européen des Membranes (IEM), UMR 5635 (CNRS-ENSCM-UM) , Université Montpellier , Place E. Bataillon, F-34095 Montpellier , France.
authors.forename: Stephan
authors.initials: S
authors.lastname: Brosillon
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006207:Half-Life; D006540:Herbicides / Q000737:chemistry / Q000528:radiation effects*; D010084:Oxidation-Reduction; D010671:Phenylurea Compounds / Q000737:chemistry / Q000528:radiation effects*; D010782:Photolysis; D013472:Sunlight; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D002264:Carboxylic Acids; D005290:Ferric Compounds; D006540:Herbicides; D010671:Phenylurea Compounds; C000499:ferric oxide; C010727:fenuron
keywords: Fe(III)–oxalate complex; fenuron; hydroxyl radicals; natural iron oxide; photodegradation