Degradation of chlothianidin from Dantutso 50WG in electrochemical process: Kinetics and role of reactive species

Abstract

The kinetic degradation of clothianidin (CLO) (in Dantuso 50 WG) during electrochemical oxidation (EO) process using sulfate- and chloride-supporting electrolytes was comprehensively investigated. The degradation of CLO was not due to direct electron oxidation, but was mainly due to •OH and other radicals generated from supporting electrolytes. The degradation of CLO was significantly inhibited when increasing the concentration of nitrobenzene (NB), methanol (MeOH) and benzoic acid (BA). The second-order rate constant of •OH toward CLO was determined to be 3.23×109 M-1 s-1 using competition kinetics method. When SO42- and Cl- were used as supporting electrolytes, the degradation of CLO by •OH was the same with kCLO = 0.0084 min-1. Meanwhile, the higher removal of CLO in SO42--supporting electrolyte was due to the contribution of (SO4•-/S2O82-) more than that of (Cl•/HClO/ClO-).