Synergism between non-thermal plasma and photocatalysis: Implicationsin the post discharge of ozone at a pilot scale in a catalytic fixed-bed reactor

This study focuses on Butyraldehyde (C4H8O) degradation using catalytic ozonation oriented to the optimization of non-thermal plasma/photocatalytic coupled processes. After the first oxidation by non-thermal plasma coupled photocatalytic processes, a second oxidative step leading to the decomposition of the residual Butyraldehyde by Ozone is catalyzed by Mordenite, ZSM-5 and γ-alumina. The Butyraldehyde degradation in the presence of Ozone under operational parameters such as plasma energy, Butyraldehyde inlet concentration, relative humidity and the height of the catalytic bed are reported in detail. The optimum operating conditions found were: Qair = 1 m3 h-1, [C4H8O] = 100 mg m-3, SIEplasma = 18 JL-1, for Butyraldehyde degradation mediated by ZSM-5. The formation of intermediate by-products was monitored during the degradation of Butyraldehyde in the presence of Ozone and ZSM-5 catalyst to suggest a degradation pathway. The coupling of catalytic ozonation by non-thermal plasma/photocatalysis lead to the total decomposition of Ozone when catalyzed by ZSM-5and presents a positive effect on the mineralization capacity. The pollutants degradation intermediates were identified by GC-MS and the oxidative states on the catalytic bed were characterized by XPS.