Degradation of Benzene Using Dielectric Barrier Discharge Plasma Combined with Transition Metal Oxide Catalyst in Air

Abstract

In this paper, a uniform and stable dielectric barrier discharge plasma is presented for degradation of benzene combined with a transition metal oxide catalyst. The discharge images, waveforms of discharge current, and the optical emission spectra are measured to investigate the plasma characteristics. The effects of catalyst types, applied voltage, driving frequency, and initial VOCs concentration on the degradation efficiency of benzene are studied. It is found that the addition of the packed dielectric materials can effectively improve the uniformity of discharge and enhance the intensity of discharge, thus promoting the benzene degradation efficiency. At 22 kV, the degradation efficiencies of dielectric barrier discharge plasma packed with CuO, ZnO and Fe3O4 are 93.6%, 93.2% and 76.2%, respectively. When packing with ZnO, the degradation efficiency of the dielectric barrier discharge plasma is improved from 86.8% to 94.9%, as the applied voltage increases from 16 kV to 24 kV. The catalysts were characterized by XPS, XRD and SEM. The synergistic mechanism and the property of the catalyst are responsible for benzene degradation in the plasma–catalysis system. In addition, the main physiochemical processes and possible degradation mechanism of benzene are discussed.