Non-thermal plasma processing for environmental protection: decomposition of dilute VOCs in air

Non-thermal plasma processing is one of the most hopeful air-cleaning technologies to remove toxic gas contaminants in air. The historical background of the non-thermal plasma related with the electrostatics is described and the fundamental experimental system including the reactor designs and their power supplies is introduced. Some experimental results suggested the high potential of the plasma processing to decompose those toxic materials. Recent progress of the plasma technologies is reviewed. The decomposition of the dilute volatile organic compounds (VOCs) is main target of the process in this paper. The oxidation ability of the plasma is very strong (stronger than the ozone) and key points for practical usage of the process are, reliability of the process, energy efficiency of the plasma (economy) and post-processed gas treatments after the plasma processing. To improve the energy efficiency of the plasma process, combination with the catalysts is also discussed. A laser-induced fluorescence (LIF) technology is also shown as a new diagnosis of the plasma reaction.