Advanced Oxidation Degradation of Dichlorobenzene in Water by the UV/H₂O₂ Process

Through UV/H₂O₂ photocatalytic advanced oxidation technique the performance, kinetics, pathway, and mechanism of ortho-dichlorobenzene (O-DCB) in water and the effect parameters of degradating reaction were studied systematically. The results showed that the reaction of photocatalytic degradation of O-DCB was fast and accorded well with the pseudo-first-order kinetics. The roles of some parameters, such as the pH, the initial concentrations of O-DCB, H₂O₂, and some anions in reaction solution, were examined in detail. It was found that weak acidic or neutral environment was favorable to the degradation reaction and some anions slowed down the photocatalytic degradation rate. Input amount of H₂O₂ possessed the best value under specified condition. The intermediates of O-DCB degradation were also tentatively identified 2,3-dichlorophenol, 3,4-dichlorophenol, formic acid, acetic acid, and oxalic acid mainly adopting GC/MS and ion chromatogram (IC) techniques. According to this, the pathway and mechanism of UV/H₂O₂ photocatalytic degradation of O-DCB were deduced and led.

Keywords:

• UV/H₂O₂ process
• AOPs
• Ortho-dichlorobenzene
• Kinetics
• Degradation pathway and mechanism.

ACKNOWLEDGMENT

We gratefully acknowledge financial support for this work from Guangdong Province Natural Science Foundation (Grant No. 20003046; 2003C102026).

Notes

*Taken from laboratory tap.

**Taken from Pearl River of Guangzhou, which contained 0.06 mM O-DCB.