Effects of TiO2 coating on zeolite particles for NO and SO2 removal by dielectric barrier discharge process

The dielectric barrier discharge-catalyst (DBD-C) hybrid process and the dielectric barrier discharge-catalyst-photocatalyst (DBD-C-P) hybrid process were analyzed for NO and SO2 removal. In the DBD-C hybrid process, zeolite particles were used as dielectric materials and catalysts for dielectric barrier discharge; in the DBD-C-P hybrid process, zeolite particles were coated with TiO2 photocatalyst to investigate the combined effects of plasma-catalyst-photocatalyst on NO and SO2 removal. Zeolite particles were coated with TiO2 photocatalyst by means of a rotating cylindrical PCVD reactor. TiO2 photocatalyst was coated partially on the zeolite surface while preserving the porous structure of zeolite. NO and SO2 removal was studied for various process variables such as applied peak voltage, initial NO and SO2 concentrations, pulse frequency, and residence time. The effects of TiO2 photocatalyst coating on NO and SO2 removal efficiencies by the DBD-C-P hybrid process are significant for low and medium applied voltage (<14 kV). The NO and SO2 removal efficiencies in the DBD-C-P hybrid process are 1.02-3.4 times and 1.03-4 times higher, respectively, than those in the DBD-C hybrid process for the process variables used in this study. We found that the zeolite particles coated with TiO2 photocatalyst by means of a rotating cylindrical PCVD reactor could be effectively used to remove NO and SO2 in the DBD-C-P hybrid process. (C) 2013 Elsevier B.V. All rights reserved.