Post Plasma-Catalysis of Low Concentration VOC Over Alumina-Supported Silver Catalysts in a Surface/Packed-Bed Hybrid Discharge Reactor

Abstract

In this study, the degradation of benzene by the means of an optimized surface/packed-bed hybrid discharge (SPBHD) plasma combined with γ-Al2O3-supported MO x (M = Ag, Mn, Cu, or Fe) catalysts in post plasma-catalysis (PPC) system. The effects of Ag loading amount and gas hourly space velocity (GHSV) for plasma-catalysis degradation of benzene have been systematically investigated. The experimental result showed that the benzene degradation was improved and the mineralization process was greatly enhanced towards total oxidation after the combination of plasma with all MO x /γ-Al2O3 catalysts. The AgO x /γ-Al2O3 catalyst exhibited the best catalytic activity in benzene degradation than the other catalysts in PPC system. The highest benzene degradation efficiency of 96% and CO x selectivity of 99% can be obtained for AgO x /γ-Al2O3 catalyst with optimum Ag loading amount and GHSV of 15% and 22,856 h−1, respectively. Time course of benzene degradation during PPC process indicated that the plasma-induced catalytic activity of AgO x /γ-Al2O3 catalyst was temporary rather than lasting over a period after the plasma off. FT-IR analysis results revealed that the intermediate products (such as CO, HCOOH) and unwanted by-products (O3 and NO x ) generated in plasma process could be significantly inhibited by PPC process with AgO x /γ-Al2O3 catalyst.