The effect of CO2 on the plasma remediation of NxOy

Plasma remediation is being investigated for the removal of oxides of nitrogen (NxOy) from atmospheric pressure gas streams. In previous works we have investigated the plasma remediation of NxOy from N-2/O-2/H2O mixtures using repetitively pulsed dielectric barrier discharges. As combustion effluents contain large percentages of CO2, in this paper we discuss the consequences of CO2 in the gas mixture on the efficiency of remediation and on the end products. We find that there is a small increase in the efficiency of total NxOy remediation (molecules/eV) with increasing CO2 fraction, however the efficiency of NO remediation alone generally decreases with increasing CO2. This differential is more pronounced at low energy deposition per pulse. More remediation occurs through the reduction channel with increasing CO2 while less NO2 and HNOx are produced through the oxidation channel. CO is produced by electron impact of CO2 though negligible amounts of cyanides are generated. (C) 1996 American Institute of Physics.