Deep degradation of chlorobenzene in a dielectric barrier discharge coupled UV/H2O system

Chlorinated volatile organic compounds (CVOCs) are hazardous to the environment and human health. Although the catalysis technology can effectively degrade CVOCs, there are problems of catalyst poisoning and harmful byproducts. In this study, the dielectric barrier discharge (DBD) coupled wet ultraviolet (UV) system (DBD + UV/H 2 O) without catalysts was proposed for the removal of a typical CVOC chlorobenzene (CB). The CB removal rate of the DBD + UV/H 2 O system was as high as 91.8 %, and the CB mineralization rate reached 76.1 %. Furthermore, the CB removal performance of the DBD + UV/H 2 O system was stable and the CB removal rate was approximately 91 % even after 15 h of reaction. In the UV/H 2 O reactor, O 3 generated by DBD was converted to ∙OH and ∙O 2 - , which played a key role in deep CB oxidation. Based on organic intermediates and density functional theory calculations (DFT), CB was degraded mainly through the hydrodechlorination pathway in the DBD reactor, while undegraded CB and organic intermediates were deeply oxidized by UV, ∙OH, and ∙O 2 - in the UV/H 2 O reactor. This study demonstrated that DBD + UV/H 2 O system can efficiently, and deeply remove CVOCs under catalyst-free conditions.