ELECTRIC-FIELD EFFECTS ON DECOMPOSITION OF DILUTE CONCENTRATIONS OF CHCL3 AND CCL4 IN ELECTRON-BEAM GENERATED AIR PLASMA

Effects of an electric field on plasma-chemical decomposition of dilute concentrations (of order 300 ppm) of CHCl3 and CCl4 in dry and wet (almost-equal-to 10% relative humidity) air streams were studied. The atmospheric pressure, non-equilibrium plasma was produced by an electron beam. The function of the electric field is to control the average electron energy. For CHCl3, application of an electric field tended to increase decomposition markedly, with larger increases in wet air relative to dry air. For CCl4, it tended to slightly increase decomposition in dry air while decreasing decomposition in wet air. The results are qualitatively consistent with the primary decomposition mechanism of dissociative electron attachment to CHCl3 and CCl4 in competition with non-dissociative electron attachment to 02.