The decomposition of ethanethiol by a corona radical injection system, using water vapor and O3as radical source, was investigated. It is found that only 83.6% of ethanethiol can be decomposed in dry air flow with relative humidity of 13.4%. A proper quantity of water vapor injection can improve the decomposition efficiency, but which is not always increased. The maximum decomposition efficiency of 99.1% can be obtained in wet air flow with relative humidity of 74.7%. 97.6% of ethanethiol can be decomposed when the relative humidity of gas flow is 51.6%, but it is found that only 76.3% of element sulfur is converted to SO2, based on sulfur balance. However, the conversion efficiency of sulfur to SO2increases obviously with the increasing of O3injection. The decomposition efficiency of ethanethiol and conversion efficiency of sulfur to SO2can reach 99.8% and 95.3% respectively, when O3is injected into the reactor by high voltage electrode tubes with concentration of 1 g/m3 and flow rate of 300 L/h. The decomposition products are SO2, CO2and H2O, while no organic product is found, based on which the decomposition mechanism is discussed. The weakest chemical bond C-S in ethanethiol molecule is firstly decomposed to ·SH and ·C2H5radicals. ·SH can be oxidized to elemental sulfur and SO2, and ·C2H5is oxidized to CO2and H2O.

The removal of trichloroethylene (TCE) by corona discharge plasma was investigated. The influences of initial concentration, gas flow rate, injection of water vapor and ozone (O3) on removal efficiency were discussed. The results show that removal efficiency reduces with the initial concentration and gas flow rate increasing. A proper quantity of water vapor injection can improve the removal efficiency, but which is not always increased, due to the electronegative characteristic of water molecule. The maximum removal efficiency of 90.7% can be obtained in wet air flow with relative humidity of 70.6%. The removal efficiency increases obviously with O3 injection. The decomposition products are 2,2-Dichloroacetyl chloride (CHCl2COCl), carbonyl chloride (COCl2), hydrogen chloride (HCl) and carbon dioxide (CO2), based on which the decomposition mechanism is discussed. The oxygen chain reaction is the primary decomposition mechanism, and high energy electrons and active oxygen species play a leading role in the decomposition process. Therefore, removal efficiency of TCE can be improved greatly when water vapor and O3 is injected.