Chloride anion effect on the advanced oxidation processes of methidathion and dimethoate: role of Cl2?- radical

CAREGNATO, PAULA; JANINA A. ROSSO; SOLER, JUAN; A. ARQUES SANZ; DANIEL MARTIRE; GONZALEZ MONICA C

WATER RESEARCH

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2012 vol. 47 p. 351 - 362

0043-1354

The reaction of phosphor-containing pesticides such as methidathion (MT) and dimethoate(DM) with dichloride radical anions (Cl2.-)was investigated. The second order rate constants (1.3-0.4)x108 and (1.1- 0.4)x108 M1 s1 were determined for the reaction of Cl2.- with MT and DM, respectively. A reaction mechanism involving an initial charge transfer from the sulfide groups of the insecticides to Cl2.- 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 Cl2.- 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.