ELECTRON-BEAM ATMOSPHERIC-PRESSURE COLD-PLASMA DECOMPOSITION OF CARBON-TETRACHLORIDE AND TRICHLOROETHYLENE

The cold plasma decomposition of carbon tetrachloride (CCl4) and trichloroethylene (C2HCl3) at dilute concentrations in dry and wet air of atmospheric pressure was investigated. The cold plasma was generated in a tunable plasma reactor, where the electron concentration is controlled by an electron beam and the average electron energy is controlled by a superimposed sub-breakdown electric field. The energy expense for decomposition, i.e., the electron beam energy per molecule decomposed, as well as the intermediate and final decomposition products were determined. Moreover, likely reaction mechanisms for the decomposition of CCl4 and C2HCl3 are presented. These mechanisms are based on bimolecular dissociative electron attachment for both CCl4 and C2HCl3 and additionally a chlorine chain reaction for C2HCl3. The present work provides a reference for the development of an advanced oxidation process on the basis of a tunable plasma reactor. Such a process would be especially suitable for the treatment of air contaminated with chemical compounds that dissociatively attach electrons.