Preparation Of ZnSe/TiO₂and CdSe/ZnSe/TiO₂and Study On Their Photocalytic For Dye Wastewater

Dye wastewater is the main source of industrial wastewater. Because of high biological toxicity, poorbiodegradability and difficulty to degradation, dye wastewater is considered as refractory wastewater athome and abroad. The researches on treatment of these wastewaters are highlights at present.Photocatalytic oxidation based on TiO2is a new technique for water treatment. Due to non-toxicity,cheap, chemical stability and moderate reaction conditions, photocatalytic oxidation develops rapidly andbecomes hot spot recently. However, owing to the wide band gap, TiO2can only absorb the ultraviolet partof sun light. The solar energy conversion efficiency and the quantum efficiency are low, which cause lowphotocatalytic efficiency. By modifying with narrow band gap semiconductor, the spectral response rangecan be widened thus improve the quantum efficiency and photocatalytic efficiency, which is important forthe further development of photocatalysis.In the present work, two photocatalysts ZnSe/TiO2and CdSe/ZnSe/TiO2were synthesized byultrasonic method with a direct immersion ultrasonic probe based on TiO2. The photocatalyticperformances of both photocatalysts were investigated by photodegrading dye wastewater. The maincontent of this paper consists of the points below.(1) The dye wastewater treatment technology, the relevant basic knowledge of TiO2photocatalyst, andthe basic knowledge of ultrasonic chemical synthesis method were outlined.(2) Synthesize the ZnSe/TiO2and CdSe/ZnSe/TiO2composite photocatalyst by direct immersionultrasonic probe of ultrasonic chemistry method, and study its performance by using X-ray diffraction(XRD), scanning electron microscope (SEM), transmission electron mictton (TEM), uv-vis absorption and Fourier transform infrared spectroscopy characterization methods. The results show that the ZnSe/TiO2andCdSe/ZnSe/TiO2composite light catalyst not only has a absorption in the uv region, and also have goodabsorption to visible light.(3) We use rhodamine B and crystal violet as simulate industrial wastewater to conduct thephotocatalytic degradation experiment, the results show that the ZnSe/TiO2and CdSe/ZnSe/TiO2composite light catalyst showed good photocatalytic performance and usability cycles.