Purification mechanism of corona discharge coupled with dimethyl sulfoxide microemulsion for simultaneous desulfurization and denitrification

[Display omitted] •Corona discharge coupled with dimethyl sulfoxide (DMSO) microemulsion achieved simultaneous desulfurization and denitrification.•DMSO microemulsion improved the defects of plasma desulfurization and denitrification generated by corona discharge.•Theoretical calculation combined with experimental phenomena revealed the oxidative absorption of DMSO microemulsion in the system.•The mechanism of simultaneous desulfurization and denitrification was proposed. In this study, a new absorbent dimethyl sulfoxide (DMSO) microemulsion is used, and corona discharge coupled with dimethyl sulfoxide microemulsion is proposed for simultaneous desulfurization and denitrification. This study solves the problem of low efficiency of simultaneous SO2 and NO purification and avoids the problem of easy poisoning of catalysts for simultaneous desulfurization and denitrification. In addition, it makes up for the defects of low efficiency and complex products of desulfurization and denitrification by plasma alone. In this study, the effects of different corona discharge voltages, DMSO microemulsion oil–water ratio and oxygen concentration on the simultaneous removal of SO2 and NO were investigated in detail. The study showed that increasing the voltage and oxygen concentration had a significant promotion effect on the degradation of NO, but the high oxygen concentration would release part of the captured SO2. Under the best experimental conditions, the SO2 removal efficiency could reach 93.4 % and the NO removal efficiency was 84.9 %. In addition, the adsorption energy calculations combined with different initial concentrations and different DMSO microemulsion temperatures illustrate that SO2 and NO react competitively with SO bonds in DMSO and OH bonds in isoamyl alcohol in DMSO microemulsions, with SO2 being preferentially adsorbed. Finally, this study explains in detail the mechanism of simultaneous SO2 and NO degradation, showing that the reactive species generated during corona discharge can excite microemulsions to produce more reactive radicals and active substances to further improve the removal of SO2 and NO.