Decomposition of Toluene with a Combined Plasma Photolysis (CPP) Reactor: Influence of UV Irradiation and Byproduct Analysis

A combined plasma photolysis (CPP) reactor was used to study the effect of UV irradiation on the removal efficiency and byproducts of toluene decomposition. The influence of UV irradiation length on the removal rate and byproducts were compared. The results show that the toluene removal is obviously improved in the CPP reactor. The removal rate is enhanced with the increase of the UV irradiation length. The increase of removal efficiency is 7.94% and 19.1% under the UV irradiation with 5 cm and 15 cm length, respectively. UV also reduces the production of ozone significantly. It is interesting to find that the effect of UV on the carbon balance is not always increased as expected, but is related to the inlet toluene initial concentration. When the inlet toluene concentration is 300 ppm or 400 ppm, the carbon balance is enhanced by UV. When the inlet concentration is lower, in 60 ppm and 100 ppm, UV no longer plays a positive role. However, UV can change the trend of carbon balance at low initial concentrations and makes it positively related to specific input energy (SIE), which is contrary to the cases without UV.