ELIMINATION OF VOLATILE ORGANIC COMPOUNDS BY NON-THERMAL PLASMA COUPLED WITH PHOTOCATALYSIS

Abstract

Degradation of toluene vapor, which was used as representative for volatile organic compounds (VOCs), by combination of non-thermal plasma and photocatalytic reaction, was investigated in this study. The degradation took place in a tubular flow reactor with an aluminum wire aligned at the center of the tube. The inner wall of the reactor was loaded with titanium dioxide photocatalyst. Non-thermal plasma was generated as corona discharge within the reactor. Wet air mixed with toluene vapor was supplied to the reactor, while the gas at the outlet of the reactor was analyzed by GC. The impact of the input electrical current on toluene removal efficiency was investigated. The degradation was found to improve with an increase in the electrical current. Synergistic effect can be obtained from the combination of photocatalytic reaction and non-thermal plasma. Moreover, both oxygen and water play a considerable role in both processes. Oxygen is regularly related in the photocatalytic reduction as the electron acceptor whereas water participates in the formation of more highly reactive radicals. However, large amount of water gives negative results due to the competitive adsorption on the photocatalyst surface and also poisons the photocatalyst. Additionally, it was found that the photocatalytic process also increased carbon dioxide yield.