Degradation of Diuron by Electrochemically Activated Persulfate

An electrochemically activated persulfate (EC/PS) system was proposed for the degradation of herbicide diuron in this study. In the EC/PS system, the ferrous ions (Fe 2+ ) produced from iron electrode can activate persulfate to generate sulfate radical (SO 4 ·- ) as well as hydroxyl radical (OH • ). The results showed that the degradation of diuron was significantly enhanced in the EC/PS system, compared to electrocoagulation, persulfate, and Fe 2+ /PS process. Both of SO 4 ·- and OH · contributed to the degradation of diuron in the EC/PS system according to the radical scavenging studies. The pseudo first-order rate constants of diuron increased with increasing the applied currents and dosages of persulfate. pH affected the degradation of diuron indirectly through the speciation of iron and resulted in higher removal efficiency in acidic condition than in alkaline condition. Chloride, carbonate, and bicarbonate in real water inhibited the degradation of diuron dramatically through consuming SO 4 ·- and OH · and abided by the order of CO 3 2− >HCO 3 − >Cl − . This study demonstrates that the EC/PS system is a novel, efficient, promising, and environmental-friendly method to treat diuron contamination.