Photo-catalytic Degradation of Chestnut Tannin Extract on Nano-TiO2 Thin Film

摘要

Nano-TiO2 film photo-catalyst was prepared by sol-gel method using tetrabutyl titanate as the precursor. The surface morphology of the photo-catalyst film was observed by AFM; the XRD pattern of the photo-catalyst was obtained using a powder diffractometer, the photo-catalytic degradation of chestnut tannin extract (CTE) in water was investigated in the reactor with UV lamp as the light source. The study results indicated that the photo-catalytic degradation of CTE follows Langmuir-Hinshelwood kinetic equation, which means photo-catalytic degradation of CTE conforms to zero order H-L kinetic equation at high concentration and conforms to first order H-L kinetic equation at low concentration. External addition of H2O2 shows a high acceleration for the degradation of CTE, but it is limited because of the amount of light-induced electron. Effects of the photo-catalytic degradation of CTE were more favorable at initial pH far from isoelectric point of CTE; the degradation speed under alkaline condition was higher than that under acidity condition.