Decomposition of dichlorodifluoromethane by adding hydrogen in a cold plasma system

The destruction of chlorofluorocarbons (CFCs) has drawn great attention because of its well-known depletion of the ozone layer at the stratosphere. Application of RF plasma for the decomposition and conversion of dichlorodifluoromethane (CFC-12 or CCl₂F₂) is demonstrated. The decomposition efficiency (η(CFC-12)) and the fraction of total carbon input converted into CH₄ and C₂H₂ (F(CH₄+C₂H₂)) in H₂ and Ar mixtures have been investigated as a function of input power wattage, H₂/CFC-12 ratio, operational pressure, and CFC-12 feeding concentration by using response surface methodology and model sensitivity analysis. The results showed that the η(CFC-12) is over 94% and the F(CH₄+C₂H₂) is over 80% under the condition of 100 W of input power wattage, 7.0 of H₂/CFC-12 ratio, 15 Torr of operational pressure, and 7.6% of CFC-12 feeding concentration. In addition, the result of sensitivity analysis indicated that both the η(CFC- 12) and the F(CH₄+C₂H₂) are more sensitive to CFC-12 feeding concentration and input power wattage. Experimental results showed that CFC-12 could be converted into CH₄ and C₂H₂ up to 80% of conversion in a hydrogen-based RF plasma system.