Photocatalytic reduction of nitrate ion in drinking water by using metal-loaded MgTiO3-TiO2 composite semiconductor catalyst

Photocatalytic reduction of nitrate ions was examined by using Cu/MgTiO3-TiO2 catalyst in the presence of sodium oxalate as hole scavenger. Many factors such as catalyst calcination temperature, Cu:Mg atom molar ratio, different hole scavengers and different concentrations of sodium oxalate were tested to search for the optimal reaction conditions. X-ray diffraction (XRD) and Transmission Electron Micrograph (TEM) were performed to characterize the composite semiconductors catalyst. Our results indicated that Cu/MgTiO3-TiO2 catalyst calcined at 873 K showed the highest photocatalytic activity and nitrate conversion reached 39.2% after 2 h irradiation. The enhanced effect for photocatalytic nitrate reduction activity was most likely to result from the formation of composite semiconductor MgTiO3-TiO2 and the transformation of TiO2 crystalline phase. (C) 2004 Elsevier B.V. All rights reserved.