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Indexed by:期刊论文

Date of Publication:2016-01-01

Journal:CATALYSIS SCIENCE & TECHNOLOGY

Included Journals:SCIE、EI

Volume:6

Issue:11

Page Number:3788-3796

ISSN No.:2044-4753

Abstract:Cycled storage-discharge (CSD) plasma catalytic removal of benzene (C6H6) using air as the discharge gas over AgMn/HZSM-5 (AgMn/HZ) catalyst is reported in this study. The properties of AgMn/HZ catalyst were compared with HZ, Mn/HZ, and Ag/HZ catalysts in investigations of C6H6 storage capacity and plasma catalytic oxidation of stored C6H6. Among HZ, Mn/HZ and Ag/HZ catalysts, the AgMn/HZ catalyst possessed the highest breakthrough capacity of C6H6, which is almost twice than that of the unsupported HZ zeolite. For the AgMn/HZ catalyst, stored C6H6 is oxidized completely to CO2 due to the promoting effect of Ag and MnOx. On the other hand, this accelerates the oxidation rate of stored C6H6 during plasma oxidation of stored C6H6. The effects of discharge parameters on plasma oxidation of stored C6H6 over the AgMn/HZ catalyst are discussed. During the CSD process, under conditions of similar to 20000 mL h(-1) g(-1) space velocity, 6 W of input power, 0.4 vol% of absolute humidity and 24 min of discharge, the stored C6H6 conversion increased rapidly with cycle number during the first three cycles and nearly all stored C6H6 could be oxidized into CO2 thereafter. In addition, CO2 selectivity was maintained at around 100% and only a small amount of N2O (40-50 ppm) was detected during all five cycles. Temperature-programmed desorption of adsorbed C6H6 on the used AgMn/HZ catalyst indicates that the minor Ag sites, which are highly active, cannot be renewed by the air plasma, but the major Ag sites, which are normally active, are renewable. This explains the variation of stored C6H6 conversion with cycle number.