Catalytic Degradation Of Dimethyl Sulfoxide Using Liquid-Phase Pulsed Streamer Discharge

Catalytic degradation of organic compounds using liquid-phase pulsed streamer discharge was investigated, referring to how much reactive species generated by streamer discharge and the performances of homogeneous-phase and heterogeneous-phase catalytic streamer discharge for degradation of organic compounds using dimethyl sulfoxide (DMSO) as destination substrate.Through experimental study of DMSO degradation by homogenous phase (Fe²⁺, Cu²⁺, Mn²⁺, Fe3+) and heterogeneous phase (γ-Al₂O₃, Cu(II)/γ-Al₂O₃, Fe(III)/γ-Al₂O₃, Mn(II)/γ-Al₂O₃, Cu(II)Mn(II)/γ-Al₂O₃, Fe(III)Mn(II)/γ-Al₂O₃) catalytic streamer discharge, byproduct selectivity based on C and S elements in liquid-phase catalytic streamer discharge, and energy efficiency, it concluded that the primary byproducts of DMSO degradation are methanesulfinite, methanesulfonate, sulfate, formaldehyde. The ratio of DMSO degradation rates by homogeneous phase catalytic steamer discharge is Fe²⁺ : Cu²⁺ : Mn²⁺ : Fe3+ : no catalyst = 3.78 : 2.20 : 2.06 : 1.08 : 1 at the streamer discharge time of 30 min, while 76.6% degradation is achieved at 25 min under Fenton catalysis. During DMSO degradation, Fenton catalytic intermediates shows a good balance of S element, up to 86.6 98.8 % of removed DMSO moles. The ratio of intermediates selectivities is methanesulfinite : methanesulfonate : sulfate : formaldehyde = 5.0 : 15.9 : 1 at the streamer discharge time of 45 min. adding O2 lowers the DMSO degradation due to impediment of streamer discharge. Unitary- and binary- metal supportedγ-Al₂O₃ of Mn showe a different catalytic extent to DMSO degradation compared with that of Cu. The main byproducts from the selectivity view are methanesulfinite and methanesulfonate for Mn, whereas HCHO for Cu, indicating that Cu has a more complete catalytic oxidation to DMSO. Considering energy consuming, homogeneous catalytic degradation of DMSO by streamer discharge is more effective than heterogeneous catalysis and the maximum energy efficiency in this study is 0.0124 mol-DMSO/kWh of G37% from Fe²⁺ homogeneous catalysis.It was carried out that chemical reaction model was set up for comparing with experimental datas in order to explore the mechanism of DMSO degradation and the parametric sensitivity analysis model was set up for estimating the contributions of streamer discharge sub-system and Fenton sub-system to DMSO degradation was also carried out. Modeling the DMSO degradation by Fenton catalytic streamer discharge satisfied with the experimental data, in which the main intermediate radicals and reactive radicals were also determined as CH3S(O)2O2·, CH3S(O)2O·, HO2?, O2-?, and ?OH. Parametric analysis indicated that the streamer discharge sub-system make a larger contribution to DMSO degradation compared with the Fenton sub-system and adding Fe²⁺ has a optimal value owing to the fact that DMSO degradation is also sensitive to initial conditions of the degradation system.