Dilute Trichloroethylene Decomposition by Non-Thermal Plasma -Catalyst and Humidity Effect, and OH Radical Behavior-
Y. Nakagawa1, Y. Tomimura1, R. Ono2, and T. Oda1
1Department of Electrical Engineering, The University of Tokyo, Japan
2Department of Advanced Energy, The University of Tokyo, Japan
Abstract- Dilute trichloroethylene (about 250 ppm TCE) in air was decomposed by the non-thermal plasma processing. Two factors were focused. One is the amount effect of the ozone decomposition catalyst. The authors reported already that the energy efficiency of dilute TCE decomposition was much improved if the catalyst is enough but the maximum efficiency was not yet realized. Moreover, the residual ozone concentration was still pretty high at high specific energy density of 100 J/L. Especially that concentration should be less than 0.1 ppm if the processed gas was exhausted in the living space. If the catalyst amount is enlarged for the same volume gas flow rate, higher decomposition efficiency is observed. Most TCE (more than 90%) is decomposed at SED of 10 J/L, when the 3 g catalyst was used in this case but carbon balance was not so high. Moreover, the leakage of the ozone was pretty high if SED is more than 20 J/L. As the second target, humidity effect for the decomposition efficiency was investigated again and some new results were obtained. The former experiment was done at dry condition (no artificial humidifying) but the decomposition efficiency was improved at the humidity of 20% (still pretty dry). That fact will be explained by the generation and behavior of OH radicals. OH radical is observed by laser-induced fluorescence method.
Keywords- Atmospheric plasma, pollution control, plasma catalytic effect, OH radical