High-efficiency destruction of aromatic VOC mixtures in a MoS2 cocatalytic Fe3+/PMS reaction

Abstract

Advanced oxidation processes (AOPs) has been intensively applied for the treatment of single VOCs but rarely for that of mixture in a wet scrubber system. However, a multitude of VOCs are present simultaneously in industries. This work first studied the degradation of a typical toxic aromatic VOC (AVOC, chlorobenzene, styrene, toluene) mixture in a MoS2 cocatalytic Fe3+/PMS (peroxymonosulfate) reaction. Extensive HO, SO4- and O2- from the efficient activation of PMS and molecular O2 cooperated well in the simultaneous removal of multiple AVOCs. The degradation of AVOCs in the mixture was significantly affected by the existence of different pollutants. For example, the toluene removal efficiency was 91 % and 74 % in the presence of styrene and chlorobenzene, respectively. Compared with that in the single-pollutant system, chlorobenzene degradation in the presence of toluene was more complex due to the generation of dichlorobenzene and toluene via an e-aq-mediated reaction. The diverse molecular structure, adsorption behavior and ring-opening process of AVOCs on the MoS2 (001) surface accounted for their different degradation performances. Molecular O2 was involved in AVOC mixture degradation and significantly shortened their degradation pathways due to the generation of more reactive benzaldehyde and benzoquinone. The total hazard index (HI) of the purified waste gas was 5.06 × 10-1 and within the safe range for human health. This study is expected to drive great advances in the simultaneous degradation of VOCs mixture by AOPs.