In this study, the photoadsorption properties of Ag ions in a AgNO3 solution by a TiO2 nano-powder synthesized by a homogeneous precipitation process at low temperature were investigated. It was found that the photocatalytic reduction in the AgNO3 solution occurred by the TiO2 nano-powder even under sun light irradiation, although the reduction of Ag ions was slow with a small adsorption of 9.32 ppm. Notably the Ag adsorption was promoted in dark conditions probably owing to the chestnut-bur shape of the TiO2 nano-powder itself. With the application of UV the Ag ions were completely adsorbed within 120 minutes, showing a more significant photocatalytic reaction. The measured adsorption reaction rate and adsorption equilibrium rate constants were 0.0004 g/minute and 1494.20 (120 m2/g), respectively.

Keywords: TiO2, Ag, Photocatalytic reaction, Photoadsorption