A combined multistage corona discharge and catalytic system for gaseous benzene removal

Non-thermal plasma is an effective and economic alternative method for removing volatile organic compounds (VOCs) since it can be operated in ambient conditions, resulting in low energy consumption, compared with the conventional methods. The main purpose of this work was to apply a combined plasma and catalytic system for VOC removal. A four-stage plasma and catalytic reactor system was set up to investigate the oxidation of gaseous benzene. The experimental results showed that an increase in either applied voltage or stage number of plasma reactors enhanced both benzene conversion and CO2 selectivity, which was in contrast with the effects of frequency and feed flow rate. Commercial TiO2 (Degussa P25), sol-gel TiO2, and 1% Pt/sol--gel TiO2 were used as catalysts in the present study. The presence of all studied catalysts hardly affected the benzene conversion, but markedly increased the CO2 selectivity. The synergistic effect of catalysts in the plasma reactor system reasonably resulted from the activation of TiO2 by the energy generated from the plasma, leading to the enhancement of the CO oxidation. (c) 2006 Elsevier B.V. All rights reserved.