Journal of Physical Chemistry A, Vol.108, No.40, 8341-8345, 2004
A mechanism for the destruction of CFC-12 in a nonthermal, atmospheric pressure plasma
The destruction of CFC-12 (CF2Cl2) has been studied in an AC, nonthermal, atmospheric pressure plasma reactor packed with barium titanate beads. The extent of the destruction in air ranges between 8% and 40% depending on the conditions. The decomposition products in air as determined by infrared spectroscopy are CO, CO2, and COF2. It is deduced that the undetected chlorine and fluorine is present as F-2 and Cl-2. A chemical mechanism for the decomposition is proposed. Large concentrations of NO, NO2, and N2O are also formed. Destruction in a stream of pure N-2 is about twice as effective as in air under corresponding conditions. The addition of a small amount of water (similar to0.03%) or oxygen (similar to0.02%) to the nitrogen carrier gas increases the destruction efficiency but the presence of molecular hydrogen (less than or equal to2%) brings about no enhancement. It is suggested that in all cases, the primary decomposition step involves dissociative electron attachment to the CF2Cl2. This is confirmed by the observed differences in the destruction in pure nitrogen and in air.