Photocatalytic Degradation of Low Level Toluene in the Gas Phase
低浓度甲苯的气相光催化降解研究

Photocatalytic degradation of low level toluene in the gas phase at low retention time (17s-83s) was studied. The effects of the inlet concentration, retention time, relative humidity, ultraviolet wavelength and carrier of the catalyst were investigated, as well as the change of the photocatalytic degradation capability with the load. It was showed that the degradation rate of toluene at low retention time decreased with increase of inlet concentration, and it decreased more significantly at shorter retention time. Within a range of retention time, the degradation of toluene followed with first order kinetics approximately, and the reaction rate constant increased with inlet concentration. The relative humidity affected the degradation rate a little when the inlet concentration was low. The photocatalytic degradation rate when irradiated with low-pressure mercury lamp (254 nm) was significantly higher than that irradiated with black light lamp having same power. The photocatalyst coated on the stainless steel mesh showed higher activity while it was on the mesh with higher number, however it was not as good as the photocatalyst coated on the aluminum plate.