Effectiveness and pathways of electrochemical degradation of pretilachlor herbicides

Pretilachlor used as one kind of acetanilide herbicides is potentially dangerous and biorefractory. In this work, electrochemical degradation of lab-synthetic pretilachlor wastewater was carried out with Sb doped Ti/SnO2 electrode as anode and stainless steel as cathode. The effect of current density on pretilachlor degradation was investigated, and the degradation pathway of pretilachlor was inferred by analyzing its main degradation intermediates. The results showed that the removal of pretilachlor and TOC in treatment time of 60 min were 98.8% and 43.1% under the conditions of current density of 20 mA cm−2, initial concentration of pretilachlor of 60 mg L−1, Na2SO4 dosage of 0.1 mol L−1, pH of 7.2, respectively, while the energy consumption was 15.8 kWh m−3. The main reactions for electrochemical degradation of pretilachlor included hydroxylation, oxidation, dechlorination, C-O bond and C-N bond cleavage, resulting in the formation of nine main intermediates.