Catalytic Dechlorination of Gas-phase Perchloroethylene under Mixed Redox Conditions.

The validity of a new method to destroy gas-phase perchloroethylene (PCE) is demonstrated at bench scale using a fixed-bed reactor that contains a Pt/Rh catalyst. Hydrogen and oxygen were simultaneously fed to the reactor together with PCE. The conversion efficiencies of PCE were sensitive to H(2)/O(2) ratio and reactor temperature. When the temperature was >/= 400 degrees C and H(2)/O(2) was >/= 2.15, PCE conversion efficiency was maintained at >/= 90%. No catalyst deactivation was observed for over two years, using only mild, convenient regeneration procedures. It is likely that PCE reduction steps precede oxidation reactions and that the importance of oxidation lies in its elimination of intermediates that would otherwise lead to catalyst poisoning. In practice, this catalytic dechlorination method holds potential for low-cost, large-scale field operation.