Enhancement of the non-thermal plasma-catalytic system with different zeolites for toluene removal

Abstract

Based on the important effect of catalyst on the plasma-catalytic system, various types of zeolites (5A, HZSM-5, Hβ, HY and Ag/HY) were chosen as catalysts to remove toluene under non-thermal plasma conditions in this work. The results showed that all the zeolites, with or without toluene adsorption abilities, significantly enhanced the toluene removal efficiency in the plasma discharge zone. Moreover, the carbon balance and CO₂ selectivity showed the same tendency of Ag/HY > HY > Hβ (HZSM-5) > 5A, which was basically consistent with toluene adsorption ability, while being opposite to the ozone emission. Loading silver on the zeolite greatly decreased organic byproduct emission, and further improved the mineralization of toluene oxidation. At the same time, the intermediates including ring-opening products on the catalyst surface were identified, and the pathways of toluene decomposition were proposed.