Photocatalytic degradation of toluene on SiO2/TiO2 photocatalyst in a fluidized bed reactor

摘要

Silica supported titania photocatalyst, SiO2/TiO2, is prepared by the sol-gel doping method using titanium tetra isopropoxide as the precursor and nitride acid as the acid catalyst. The structure and physical properties of SiO2/TiO2 particles are characterized by SEM/EDS, XRD, and BET specific surface area measurement. When a small amount of TiO2 coated onto the silica gel surfaces, the BET specific surface area of the SiO2/TiO2 particles increases. However, when the ratio of SiO2/TiO2 precursor decreases, TiO2 fills the pores of silica gel and the BET specific surface area of SiO2/TiO2 particle decreases. The as-prepared SiO2/TiO2 particles are used as the fluidizing media in a fluidized bed photoreactor and toluene is degraded therein. The results show that the contaminated stream containing toluene with the concentration as high as 1000 ppm can be continuously degraded in the fluidized bed photoreactor. The continuous toluene removal efficiency is around 30%-40% at steady state.