Degradation of diuron in aqueous solution by dielectric barrier discharge.

Degradation of diuron in aqueous solution was conducted in a dielectric barrier discharge (DBD) reactor and the proposed degradation mechanism was investigated in detail. The factors that affect the degradation of diuron were examined. The degradation efficiency of diuron and the removal of total organic carbon (TOC) increased with increasing input power, and the degradation of diuron by DBD fitted first-order kinetics. Both strong acidic and alkaline solution conditions could improve diuron degradation efficiency and TOC removal rate. Degradation of diuron could be accelerated or inhibited in the presence of H2O2 depending on the dosage. The degradation efficiency increased dramatically with adding Fe2+. The removal of TOC and the amount of the detected Cl-, NO3- and NH4+ were increased in the presence of Fe2+. The concentrations of oxalic and acetic acids were almost the same in the absence and presence of Fe2+, but high concentration of formic acid was accumulated in the presence of Fe2+. The main degradation pathway of diuron by DBD involved a series of dechlorination-hydroxylation, dealkylation and oxidative opening of the aromatic ring processes.