| The utilization of solar energy, a clear energy, control and treatment of environmental pollution are important problem that should be faced and resolved in 21th century. So the research and development on cheap photocatalysts with high performance, which can utilize solar energy directly and environmental friendly, have enormous social and economic benefit.Nano N/TiO2 powders with visible-light activity were prepared by Sol-Gel method under mild condition, with nitrogen source from urea, salvolatile and ammonia, respectively, which are all low toxic or nontoxic, abundant materials with simple structure. A systematic study of the preparation with different nitrogen source and different doping mode, characterization and photocatalytic activity under different kinds of light were presented. The influence of photoreaction kinetic constants kr and adsorption equilibrium constants Ka on the apparent reaction kinetic constants kap was analysed with the integral mode of the Langmuir-Hinshelwood kinetics in the photodegradation process of dye methyl orange and achromaticity 2-mercaptobenzothiazole. The end products, pH alteration of photodegradation process and the influence of pH on system were investigated. The application of N/TiO2, loading on the surface of hollow sphere ofγ-Al2O3, to the fluid-bed reactor was investigated preliminarily.The crystal structure, particle size, surface area, and optical absorption properties of N/TiO2 with different nitrogen source had been investigated by means of XRD, TEM, BET, UV-Vis DRS, TG-DSC and XPS. The results were showed as follows:①The crystal structure of N/TiO2 calcined at 350-500℃were all anatase, which was maturity with increase of calcination temperature, and changed into rutile at 600℃. The crystal size increased with doping, and augment with increase of N/Ti proportioning.②Nitrogen doped into TiO2 lattice to form N-Ti-O, which was proved byβ-N1s at 396eV by XPS. There was independent narrowband N2p lied upper side of O2p, which induced no red-shift with N/TiO2. The optical adsorption intensity of yellow N/TiO2 enhanced with increase of N/Ti proportioning, and weakened with increase of calcination temperature and calcination time. The darker the color was, the stronger the optical adsorption was in visible light region.③Due to decomposition of urea and salvolatile, volatilization of ammonia, and the oxidation of nitrogen into NOx, N/TiO2 formed multiporous structure. The specific area of N/TiO2 prepared with nitrogen source from urea, salvolatile, and ammonia were 139.31, 132.76, 116.32m2/g, respectively, which were about two times as that of TiO2, and supplied advantage condition for adsorption of organic substance on N/TiO2.④The doping of nitrogen induced the formation of oxygen-vacancy and then induced Ti3+, the percent of Ti3+ and surface hydroxyl group increased with increase of N/Ti proportioning.Photocatalytic degradation of methyl orange and 2-mercaptobenzothiazole in N/TiO2 suspension with different nitrogen source irradiated by tungsten halide lamp and high-pressure mercury lamp was comparatively investigated. The results showed as follows:①N/TiO2 exhibited higher visible-light activity than TiO2 in the degradation of methyl orange and 2-mercaptobenzothiazole under the irradiation of tungsten halide lamp filtered part of UV light. Due to effect of Ti3+ and surface hydroxyl group, there was an optimal doping of N/Ti proportioning exhibiting highest visible-light activity with 20mol%, 20mol% and 4mol% for urea, salvolatile and ammonia, respectively. The visible-light activity of N/TiO2 weakened with increase of calcination temperature and calcination time, and N/TiO2 calcined higher than 600℃showed no visible-light activity.②Due to the presence of independent narrowband N2p, N/TiO2 would exhibit much higher activity for degradation of organic substance under the irradiation of high-pressure mercury lamp than the irradiation of tungsten halide lamp, and it showed worse UV-light activity than TiO2.③Compared to N/TiO2, N/TiO2 with non-uniform doping showed higher UV-light activity and poor visible-light activity.According to the adsorption equilibrium constants Ka, the systematic study of kinetics should be adopted with integral mode of the Langmuir-Hinshelwood kinetics in the photodegradation process of methyl orange and 2-mercaptobenzothiazole. As a result, adsorption amount of organic substance on N/TiO2 enlarged by nitrogen doping, and adsorption amount of 2-mercaptobenzothiazole was more than that of methyl orange. The effect of photoreaction was higher than that of adsorption in the system of methyl orange, and the reverse results in the system of 2-mercapbenzothiazole. The difference was related to molecular structure and function group of organic substance. Compared to TiO2, kap of N/TiO2 improved obviously, corresponding to about 13.79 times in the system of methyl orange, and 8.10 times in system of 2-mercaptobenzothiazole.The application of N/TiO2 loading on the surface of hollow sphere ofγ-Al2O3 to the fluid-bed reactor was investigated preliminarily under irradiation of tungsten halide lamp, which exhibited some activity. Such factors as dip-coating mode, existence of oxygen or without oxygen, presence of H2O2 were all investigated. The results showed that multi-dip-coating mode, existence of oxygen and H2O2 would improve the photoactivity.The photocatalytic degradation process and products were investigated by means of UV-Vis adsorption spectra, TOC, CODcr, ion chromatography. Due to the formation of small molecule organic acid during the degradation process, the value of pH decreased appreciably.In addition, the condition of basic or acid would generate infaust effect in the system of 2-mercapbenzothiazole.
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