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Nanometer titanium dioxide (TiO2) can degradated completely toxic organic pollutants into harmless carbon dioxide and water. Due to its high photo-catalytic acitivity, high chemical stability and harmless, the photocatalyst TiO2 has been widely investigated and used. However, the use of this photocatalyst is currently limited for that light irradiation with rather short light wavelength is needed for the occurrence of the photo-catalytic rea-ction. Research on the doping and modification of TiO2, which aims at extending its optical response scope from the ultraviolet light (wavelength-range 300-400nm) to the visible sp-ectral range (wavelegth-range 400-800nm), will promote the photocatalysis technology in practical wastewater treatment.In this paper, N, Zn co-doped TiO2 (Abbreviation NZTO) nanometer photocatalysts, which have photo-catalysis in invisible spectral rang, were prepared with TiOSO4 and ZnSO4·7H2O as raw materials, NH3·H2O as precipitant by co-precipitation method. The in-fluence factors on average diameter of NZTO powders were inspects, such as pH, reaction temperature, precipitant concentration, reaction time and so on. It was characterized by TG-DTA, XRD and UV-VIS so on. The results showed that under the optimal condition, pH value of 7, NH3·H2O concentration of 7mol/l,30min reaction time, common temperature, the NZTO powders had 24.5nm average diameter. Its absorption range was extended to the visible rang and photocatalysis ratio was higher than un-doped TiO2 nano-meter powders.Azo dyes, methyl orange was used as the pollution reactant to evaluate the photo-catalytic activity of the NZTO catalyst samples by orthogonal experiments. The results showed that the optical conditions on degradation of methyl orange is the initial concen-tration of 5mg/L, pH values of 1, NZTO photo-catalyst dosage 1g/L, oxidant dosage(H2O2) 0.8ml/500mL. In addition, influence factors, such as pH, Zn coped weight, calcine temp-erature, were inspected on degradation ratio of the NZTO powders by orthogonal experi-ments. The results showed that the optimum condition is Zn 2wt%, pH values of 7, calcine temperature of 500℃. Verification experiment in the optimum conditions showed that the degradation ratio of methyl orange reached 98.2%, under sunshine for 6h, with ultrasound dispersing and whipping, and it’s still 74.2% four times reused.
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