| The properties, principles and applications of the nanomaterials were summarized. The progress of nano TiO2 photocatalyst and its contribution to water treatment were introduced. TiO2 nanoparticles and modified TiO2 nanoparticles were prepared, The structure of the prepared products were characterized by X-Ray diffraction (XRD), transmission electron microscopy (TEM) and infrared spectroscopy(IR). The factors among the sol-gel process were studied. A Series of photocatalytic oxidation reactions to p-nitrophenol were designed.TiO2 nanoparticles photocatalysts were prepared by Sol-Gel process. TG, TEM, and XRD methods characterized the properties such as composition and microstructure of the prepared TiO2 nanoparticles. Hydrochloric acid contributed to stabilize the sol during hydrolytic polycondensation. Deficiency of hydrochloric acid would lead to particle precipitation, while over dosage would result in particle reunite. Factors influencing TiO2 photocatalystic properties were discussed. TiO2 nanoparticles were prepared via sol-gel method, the morphology, grain size and crystalline phases of TiO2 powders were investigated with X-Ray diffraction (XRD) and transmission electron microscopy (TEM). Results indicated that the appearance of TiO2 nanoparticles was spherical and particle size was in the range from 10 to 30nm.Serieses of Fe3+/TiO2 and Ag/TiO2 nanoparticles were synthesized using the sol-gel method, The structure of the prepared products were characterized by TG, XRD and TEM. Appearance of TiO2 nanoparticles was spherical and particle size was in the range from 10 to 30nm. The modified TiO2 nanoparticles were prepared by a solvothermal method, with the modify agent including stearic acid, benzilic acid, benzoic acid, cysteine and histidine. The structure of the prepared product was characterized by infrared spectroscopy(IR). The experimental results show that the organic acid has changed the microstructure of TiO2 nanoparticles. The pore-size dispersion of modified TiO2 nanoparticles was enhanced as well. A CdS/TiO2 photocatalyst was successfully synthesized using the hydrothermal method, The structure of the prepared product was characterized by XRD and TEM methods. The experimental results show that the product was some kind of composite crystal formed with CdS and TiO2, which shows a 3-D network structure.A photocatalytic oxidation reaction to p-nitrophenol was designed. Factors control the photocatalytic oxidation reaction were studied in detail, including heating temperature for TiO2 nanoparticles, initial concentration of p-nitrophenol, initial solution pH and reaction time. Results indicated that: Elevating reaction temperature contributed to the transformation of TiO2 nanoparticles from anatase to rutile. The temperature range for transformation is from 450℃to 600℃. Best photocatalytic efficiency can be obtained when TiO2 nanoparticles was sintered at 550℃. Constant of reaction rate decreased and the initial reaction rate increased with the increase of initial concentration of p-nitrophenol. The possible reason for this might be that the former related to the adsorption ratio of p-nitrophenol on catalysts while the latter related to the amounts of adsorbed p-nitrophenol. pH value of the solution had obvious effects on the photodegradation reaction. Reactions were favored under acidic conditions and inhibited to some extent under alkaline conditions. The photocatalytic oxidation reaction of modified TiO2 photocatalysts show that the photocatalytic activity was enhanced within the modification process. |
