title: Chloride anion effect on the advanced oxidation processes of methidathion and dimethoate: role of Cl2(·-) radical.
abstract: The reaction of phosphor-containing pesticides such as methidathion (MT) and dimethoate (DM) with dichloride radical anions (Cl(2)(·-)) was investigated. The second order rate constants (1.3 ± 0.4) × 10(8) and (1.1 ± 0.4) × 10(8) M(-1) s(-1) were determined for the reaction of Cl(2)(·-) with MT and DM, respectively. A reaction mechanism involving an initial charge transfer from the sulfide groups of the insecticides to Cl(2)(·-) is proposed and supported by the identified transient intermediates and reaction products. The formation of chlorinated byproducts was determined. The unexpected consequences of an efficient Cl(2)(·-) reactivity towards MT and DM on the degradation capacity by Advanced Oxidation Procedures applied to polluted waters containing the insecticides and Cl(-) anions is discussed.
authors.affiliation: Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina.
authors.forename: Paula
authors.initials: P
authors.lastname: Caregnato
authors.forename: Janina A
authors.initials: JA
authors.lastname: Rosso
authors.forename: Juán M
authors.initials: JM
authors.lastname: Soler
authors.forename: Antonio
authors.initials: A
authors.lastname: Arques
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Mártire
authors.forename: Mónica C
authors.initials: MC
authors.lastname: Gonzalez
mesh_terms: D000838:Anions; D002712:Chlorides / Q000737:chemistry*; D003198:Computer Simulation; D004117:Dimethoate / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry*; D007700:Kinetics; D008962:Models, Theoretical; D009946:Organothiophosphorus Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D000838:Anions; D002712:Chlorides; D007306:Insecticides; D009946:Organothiophosphorus Compounds; D014874:Water Pollutants, Chemical; D004117:Dimethoate; C005828:methidathion