Degradation of diuron by persulfate activated with ferrous ion

The degradation of diuron by persulfate (S2O82-, PS) activated with ferrous ion (Fe2+) was investigated. The PS-Fe2+ system achieved high levels of reduction of diuron (90%). The optimal PS/Fe2+ molar ratio for diuron reduction was found to be 1:1. A chelating agent, sodium citrate, was used to control the amount of Fe2+ in solution for activation of the oxidant, with the optimum results obtained when the molar ratio of citrate and Fe2+ was 1:1. A reductive chemical, hydroxylamine, was also applied into the PS-Fe2+ system, and the hydroxylamine/Fe2+ molar ratio of 2:1 significantly increased the degradation of diuron due to enhancement of redox of Fe3+ to Fe2+. The main degradation product of diuron was 1-(3,4-Dichlorophenyl)-3-methylurea(DCPMU); SO4 center dot attack did not cause the opening of the aromatic ring of diuron. (C) 2012 Elsevier B.V. All rights reserved.