The hybrid effect of non-thermal plasma and activated carbon-zinc oxide nanocomposite on the removal of volatile organic compounds in air

Regarding high emission rates of volatile organic compounds in the atmosphere by different industrial and transportation sources and their adverse effects on human health and the environment, the need to remove these chemicals from gas streams using new technologies with low energy consumption and high efficiency has been more evident. In this study, the catalytic effect of AC-ZnO was investigated on the removal of these compounds (toluene) and their product distribution in a hybrid catalytic plasma system.
AC-ZnO catalyst was prepared using sol-gel method. Non-thermal plasma was generated utilizing a high voltage power supply and a dielectric barrier discharge reactor. Plasma and catalyst techniques were then combined in a two-stage configuration. Reactor influent and effluent air sample analysis was carried out using GC-MS and on-line gas monitoring devices.
The results showed that there was a high synergistic effect between plasma and catalyst so that the total removal of toluene was obtained at specific input energy of 1000 J L-1, while the removal percent was around 88% at the same energy delivery with plasma-alone system. The selectivity towards CO2 was also increased over catalyst bed and some of the by-products such as NO, and NO2 were totally removed and the effluent amount of O3 was negligible.
It can be concluded that the plasma-catalyst hybrid technique is a new and promising method for the removal of volatile organic compounds causing the increase of removal efficiency, and the hazardous products and energy consumption reduction.