Solar photocatalytic degradation of dye wastewater in the presence of heat‐treated anatase TiO₂powder

The phase transformation from anatase to rutile of titanium dioxide (TiO2) was attempted by heat-treatment and a novel TiO2 catalyst with high photocatalytic activity under sunlight irradiation was obtained. The beat-treated anatase TiO2 powders at various transition stages were characterized by X-ray diffraction (XRD), fourier transform infrared (FTIR), and transmission electron microscopy (MM). The tests of photocatalytic activities of the beat-treated anatase TiO2 powders were conducted by the photocatalytic degradation of rhodamine B in aqueous solution under sunlight irradiation. The results reveal that the anatase TiO2 powder beat-treated at 700 degrees C for 60 min shows the highest photocatalytic activity, which can effectively degrade rhodamine B in aqueous solution under sunlight irradiation. The remarkable improvement of photocatalytic activity of the anatase TiO2 powders was mainly elucidated by the formation of special interphase between rutile and anatase phases, which can limit the recombination of photo-generated electrons and holes efficiently. Therefore, this method may be envisaged as a technology for treating dye wastewaters using solar energy. (C) 2008 American Institute of Chemical Engineers Environ Prog.