title: Photocatalytic degradation of 2,4-dichlorophenoxyacetic acid and 4-chloro-2-methylphenoxyacetic acid in water by using TiO2.
abstract: The photocatalytic degradation of many chlorinated organic compounds by semiconductor particles, has been widely recognised as a promising method of water and wastewater treatment process. In the present work the photocatalytic transformation of 2,4-D and MCPA in aqueous solution with 2 g l(-1) suspended TiO2 is demonstrated. The formation of several intermediates has been observed. The photodegradation rate increases with increasing pH. The photocatalytic transformation of 2,4-D and MCPA over TiO2 in solution containing hydrogen peroxide has been also studied. H2O, accelerated significantly the reaction rate of 2, 4-D and MCPA. The partial inhibition by ethanol is attributed to the scavenging of OH radicals involved in the first step of the reaction. Finally, from these results, a mechanism is proposed. This photocatalytic method has good potential for application on a large scale.
authors.affiliation: Laboratoire des Sciences et Technologie de l'Environnement, Université Mentouri-Constantine, Campus Chaâb Errassas, Constantine 25000, Algeria.
authors.forename: K
authors.initials: K
authors.lastname: Djebbar
authors.forename: A
authors.initials: A
authors.lastname: Zertal
authors.forename: T
authors.initials: T
authors.lastname: Sehili
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000378:metabolism*; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000031:analogs & derivatives / Q000378:metabolism*; D002384:Catalysis; D006540:Herbicides / Q000378:metabolism*; D006861:Hydrogen Peroxide; D010777:Photochemistry / Q000379:methods; D014025:Titanium / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D006540:Herbicides; C009495:titanium dioxide; D015084:2,4-Dichlorophenoxyacetic Acid; D006861:Hydrogen Peroxide; D014025:Titanium; D008456:2-Methyl-4-chlorophenoxyacetic Acid