| In this experriment, supported TiO2 photocatalyst was prepared onto activated carbon fiber, and the photocatalytic degradation experiment was carried out on the self-made photoreactor at high concentration level. Many influencing factors were investigated in detail. A new approach and principle of SO2 and NOx simultaneous removal from flue gas was presented by TiO2 potocatalyst based on visible light technology.The chemical and micro-structure analysis on the products of the desulfurization and denitrification reactions were analysed, the mechanism of simultaneous desulfurization and denitrification by photocatalytic oxidation was deduced. On the basis of the experimental reaction condition, the desulfurization model and the denitrification model were proposed.Mixing nano-crystalline TiO2 photocatalyst was prepared by twice hydrolysis method, and nano-anatase TiO2 catalyst was prepared by sol-gel method. Supported TiO2 /ACF photocatalyst was prepared by dip-coating method.The performance of TiO2 photocatalyst was characterized by SEM, TEM and XRD. The nanometer TiO2 existed and the particle size of mixing nano-crystalline and nano-anatase TiO2 photocatalyst were 10nm and 22.8nm, respectively.The photocatalytic activity of mixing nano-crystalline TiO2 photocatalyst was evaluated by degradation of methyl orange.The results provided prerequisite for the next application of simultaneous desulfurization and denitrification of flue gas.SO2 and NOx could be adsorbed by TiO2 photocatalyst without visible light, and the photolysis and oxidation of couldnot occured by TiO2 photocatalyst. Visible light irradiation plays a vital role in photocatalytic desulfurization and denitrification.Presence of O2, humidity of flue gas, temperature and initial concentration of SO2 and NOx were most essential factors to photocatalytic oxidiation of SO2 and NOx. The photocatalytic oxidation was primary in the removal process of SO2 and NOx. Under the optimum experimental conditions,the removal efficiency of 88.4% for SO2 and of 40% for NOx with nano-anatase TiO2 photocatalyst were obtained respectively. And the higher removal efficiency of 97% for SO2 and of 51.2% for NOx with mixing nano-crystalline TiO2 photocatalyst were obtained respectively.The results showed that under the visible light irradiation, the activity of mixing nano-crystalline TiO2 photocatalyst was higher than that of nano-anatase TiO2 photocatalyst.In certain concentration range, the removal of SO2 and NOx had a promotion for each other. During the concentration of SO2 among 800~2000 mg/m3, the removal of NOx was promoted gradually with the concentration of SO2 increased. The highest removal efficiency of NOx was obtained at 2000 mg/m3 of SO2. During the concentration of NOx among 600~1000 mg/m3, the removal efficiency of SO2 was increased gradually with the concentration of NOx increased.X-ray spectroscopy (EDS), a product of the chemical analysis, ion chromatography (IC) and X-ray diffraction (XRD) showed that the photocatalytic simultaneous desulfurization and denitrification products were sulfate and nitrate, the removal photocatalytic reaction mechanism of SO2 and NOx was the photocatalytic oxidation reaction,Based on SPSS multiple linear regression models and BP nerve network model, the predict model of the simultaneous desulfurization and denitrification photocatalytic efficiency was been done.The simulated results were approximately in accordance with the practical case and reached a high accuracy.
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