Preparation of photocatalytic nano-ZnO/TiO2 film and application for determination of chemical oxygen demand

摘要

A composite nano-ZnO/TiO2 film as photocatalyst was fabricated with vacuum vaporized and sol-gel methods.The nano-ZnO/TiO2 film improved the separate efficiency of the charge and extended the range of spectrum,which showed a higher efficiency of photocatalytic than the pure nano-TiO2 and nano-ZnO film.The photocatalytic mechanism of nano-ZnO/TiO2 film was discussed,too.A new method for determination of low chemical oxidation demand(COD)value in ground water based on nano-ZnO/TiO2 film using the photocatalytic oxidation technology was founded.This method was originated from the direct determination of the Mn(VII)concentration change resulting from photocatalytic oxidation of organic compounds on the nano-ZnO/TiO2 film,and the COD values were calculated from the absorbance of Mn(VII).Under the optimal operation conditions,the detection limit of 0.1 mg l~(-1),COD values with the linear range of 0.3-10.0mg l~(-1)were achieved.The results were in good agreement with those from the conventional COD methods.