Removal of Trichloroethylene by Corona Radical Injection

Abstract

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.