A novel strategy for degradation of high gaseous hourly space velocity (GHSV) benzene, toluene, xylene (BTX) by double dielectric barrier discharge (DDBD) coupled with Mn3O4/ activated carbon fibers (ACF) catalysts was proposed in this work. A series of Mn3O4/ACF catalysts were synthesized by hydrothermal method and characterized. The results showed that all the prepared catalysts could improve the degradation of BTX in DDBD system and inhibit the production of ozone. Among the catalysts with different Mn loading, the 5.6%Mn3O4/ACF, with the highest Mn(+3) content (43.2%) and the highest absorbed oxygen content (38.5%), presented the best catalytic performance. In 5.6%Mn3O4/ACF+DDBD system, the degradation efficiency of benzene, toluene and xylene could reach 49.9%, 79.7% and 97.1% respectively with SIE of 400 J L-1. The carbon balance and CO2 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 Mn3O4/ACF catalysts. The higher the Mn (Ⅲ) and absorbed oxygen, the better the catalytic performance of the Mn3O4/ACF catalysts. The organic by-products were identified by chromatography-mass spectrometry (GC-MS), and a possible reaction mechanism of BTX in DDBD reactor and catalyst surface was proposed based on the composition of organic by-products.

The removal of toluene by sepiolite supported with Fe 2 O 3 by plasma catalysis was studied. Fe 2 O 3 /SEP catalysts were prepared by impregnation and characterized by Brunauer-Emmett-Teller, inductively coupled plasma, x-ray diffractometer, scanning electron microscopy, x-ray photoelectron spectroscopy, and H 2 -TPR. Degradation efficiency of toluene under Fe 2 O 3 loading, energy yield, carbon balance, CO 2 selectivity, and residual O 3 concentration were studied. The results show that sepiolite clay as a carrier can reduce the reduction temperature of Fe 2 O 3 . Fe 2 O 3 /SEP catalyst has good moisture resistance and catalytic capacity. 5Fe/SEP has the best catalytic effect due to its high lattice oxygen content and large specific surface area. After continuous discharge at constant energy density for 48 h, the catalytic ability of 5Fe/SEP does not decrease. The results indicated that sepiolite supported Fe 2 O 3 catalyst is an efficient catalyst for toluene degradation by plasma-catalyst measure.

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