Non-thermal Plasma Processing for Dilute VOCs Decomposition Combined with the Catalyst

Abstract

Atmospheric pressure non-thermal plasma process combined with the new catalyst for volatile organic compounds, especially dilute tricholorethylene (TCE) in synthesized dry air is discussed. TCE decomposition efficiency is very good and more than 95% of TCE is easily decomposed at SED (specific energy density) of 18 Joule/litter which is practical value. However, more discharge energy is necessary to the full oxidization, which means that almost carbon included in TCE can be oxidized to carbon oxide (CO and CO₂) named as the carbon balance. For better carbon balance, SED of the electric discharge is more than 90 J/L which is pretty large. We would like to find more efficient catalyst for that purpose. The decomposition mechanisms by the non-thermal plasma should be clear and the new catalyct which decomposes the ozone and TCE simultaneously will be developed. Byproduct analysis suggested that nonthermal plasma direct process generates DCAC byproducts from TCE but the catalyst process do not generates any DCAC and the generation of only TCAA is detected indicating the atomic oxygen radical can oxidize TCE to TCAA only. The new catalyst is inserted in the plasma reactor where the diameter of the discharge electrode is thin and the catalyst can be filled in that space between the electrode and the tube wall. The electric field effect and radical life time effects are examined also.