Photocatalytic Oxidation of Gaseous Benzene under VUV Irradiation over TiO2/Zeolites Catalysts

Volatile organic compounds (VOCs) present a great risk to the atmospheric environmental as well as the public health and safety. In this study, a series of TiO2/zeolites catalysts were synthesized by sol-gel method. They showed much better photocatalytic activity for benzene degradation under UV irradiation compared with commercial TiO2 (P25), which suffered from typical catalyst deactivation. Vacuum ultraviolet (VUV) irradiation was used to further enhance photocatalytic oxidation of benzene. The VUVPCO process obtained much higher benzene removal efficiency (nearly 100%) than conventional UV-PCO (less than 10%). Besides photocatalytic oxidation, photolysis and ozone-assisted catalytic oxidation was also involved in the VUV-PCO process and they contributed much to benzene degradation. Most of the removed benzene was oxidized into CO2. Among the prepared photocatalysts, TiO2/ZSM-5 with Si/Al ratio of 200 obtained the best catalytic activity due to its appropriate porous structure and framework, which led to superior capacity for benzene absorption and ozone decomposition. (C) 2016 Elsevier B.V. All rights reserved.