Degradation of benzene, toluene, and xylene with high gaseous hourly space velocity by double dielectric barrier discharge combined with Mn ₃O ₄/activated carbon fibers

Abstract

A novel strategy for the degradation of high gaseous hourly space velocity benzene, toluene, and xylene (BTX) by double dielectric barrier discharge (DDBD) coupled with Mn ₃O ₄/ activated carbon fiber (ACF) catalysts was proposed in this work. A series of Mn ₃O ₄/ACF catalysts were synthesized using the hydrothermal method and characterized. The results showed that all the prepared catalysts could improve the degradation of BTX in the DDBD system and inhibit the production of ozone. Among the catalysts with different Mn loading, the 5.6%Mn ₃O ₄/ACF, with the highest Mn(+3) content (43.2%) and the highest absorbed oxygen content (38.5%), presented the best catalytic performance. In the 5.6% Mn ₃O ₄/ACF + DDBD system, the degradation efficiency of benzene, toluene and xylene could reach 49.9%, 79.7% and 97.1%, respectively, with a specific input energy of 400 J l ⁻¹. The carbon balance and CO ₂ selectivity, meanwhile, were 83.3% and 51.1%, respectively. It seemed that Mn(+3) and absorbed oxygen content could be a reference for the catalytic performance of Mn ₃O ₄/ACF catalysts. The higher the Mn (III) and absorbed oxygen, the better the catalytic performance of the Mn ₃O ₄/ACF catalysts. The organic by-products were identified by chromatography-mass spectrometry, and a possible reaction mechanism of BTX in the DDBD reactor and catalyst surface was proposed based on the composition of organic by-products.