Abstract:Printing and dyeing waste water is one of the key concerns of sewage treatment. The methylene blue is the typical organic pollutant in dyeing waste water. The methylene blue solution will be degraded by TiO2 particles doped Zn2+ as the photo-catalyst. The XRD pattern analysis shows that the doped ion Zn2+ has changed the ratio of anatase to rutile. Parameters during the preparation of the catalyst affect the photocatalytic degradation rate of methylene blue greatly. The pure TiO2 calcined performs the best at 450℃. The TiO2 doped Zn2+ calcined performs the best at 500℃. That catalyst dosage should be neither too high nor too low, which is not conducive to the improvement of photocatalytic activity. The degradation ratio of methylene blue is the highest when the concentration of catalyst is 1 g/L. The photocatalytic activity of catalyst is relatively high when the concentration of Zn2+ is 0.5%. As the doping amount of Zn2+ further increases, the photocatalytic activity is decreased. It becomes more difficult for ultraviolet light to reach the catalyst surface when the concentration of organic compounds is high. The utilization efficiency of light, is reduced, so the catalyst activity is getting lower. The degradation is relatively fast when the methylene blue initial concentration is 5 mg/L.