Use of oxalate sacrificial compounds to improve the photocatalytic performance of titanium dioxide

Our study demonstrated that the performance of TiO2 photocatalysts in eliminating organic compounds in water can be improved by combining them with calcium oxalate. The adsorption maximum capacity of Orange II on various pure photocatalysts is dependent on the specific area. Concerning the mixed TiO2/calcium oxalate catalysts, we observed that adsorption is still higher than that of pure correspondent photocatalysts. The influence of the sacrificial agent differs according to the photocatalyst used. Thus performance of the P25-TiO2 photocatalyst is positively slightly affected by the presence of calcium oxalate, whereas with TiO2-PC500 a decline in photocatalytic activity can be noted. The use of calcium oxalate significantly improves the performance of titanium dioxide prepared by sol–gel. We observed similar results with the kinetics of mineralization. It seems that the effect of oxygen is the same whether pure TiO2 samples or 70%TiO2/30%calcium oxalate mixtures are used, regarding the rate of conversion of Orange II after 30 min of irradiation.