DECOMPOSITION OF METHYLENE-CHLORIDE BY ELECTRON-BEAM AND PULSED CORONA PROCESSING

Experiments on the plasma-assisted decomposition of dilute concentrati ons of methylene chloride in atmospheric-pressure NZ and dry air strea ms by electron beam and pulsed corona processing are presented. This p aper presents the first experimental evidence showing that the decompo sition of methylene chloride in a non-thermal plasma at ambient gas te mperature proceeds via reaction with nitrogen atoms. The decomposition is more efficient with energy deposition in electron beam generated p lasmas because of the higher rate for electron-impact dissociation of Nz. In dry air mixtures, the decomposition of methylene chloride is de graded substantially because the nitrogen atoms are consumed in the pr oduction of nitrogen oxides. At higher gas temperatures (300 degrees C ), the decomposition of methylene chloride in dry air is shown to proc eed via reaction with oxygen atoms. The main products of methylene chl oride decomposition in dry air mixtures are CO, CO2, HCl, and probably Cl-2. (C) 1997 Elsevier Science B.V.