| In environtment protection field, it is one of key controlling objects to decontaminate phenol wastewater, which poses great harm to environment and becomes a serious problem in metallurgy industry. Photocatalytic oxidation of water contaminants is a new method for wastewater treatment. It is widely and deeply studied by researchers for its high photo degradation efficiency, none secondary pollution caused and the potential of utilitilization of solar energy. Therefore, preparation of effective laden photocatalysts and improvement of solar energy use were two impending problems in the domain of photocatlytic oxidation presently. TiO2 photocatalysts have attracted much attention due to its promising environmental application in air purification, water disinfections, hazardous waste remediation, and water purification. However, the use of conventional powder catalysts results in disadvantages in recycle and separation, also producing pollution after the reaction. Preparation of the catalyst coated as membrane then has been a focus of attention.In this paper, nanocrystalline TiO2 photocatalysts were prepared by Sol-Gel process. DTA-TG, SEM, and XRD methods characterized the composition, microstructure and properties of the prepared TiO2 powders. Factors influencing TiO2 photocatalystic properties were discussed. TiO2 nanometer membranes were prepared on glass and ceramic via sol-gel method, respectively. The morphology, grain size and crystalline phases of TiO2 membranes were investigated with scanning electron microscopy (SEM) and X-Ray diffraction (XRD). Results indicated that the appearance of nanocrystal particle TiO2 was spherical and particle size was in the range from 30 tolOOnm. Hydrochloric acid contributed to catalysis and to stabilize the sol during hydrolytic polycondensation of titanium butyrate. Deficiency of hydrochloric acid (M< 0.01) would lead to particle precipitation, while over dosage(M>0.3) would result in particle reunite.Kinetics of nano-titanium dioxide particle growth was investigated. Due to its small particle size of TiO2, it contributed to crystal phase transformation from anatase to rutile and reduced the activation energy. The obtained active energy was 129.26 kJ/mol and it was much lower than theory value.Factors controlling the photocatalytic oxidation reaction, including initial concentration of phenol, initial solution pH, oxide amounts added, reaction time,different light sources and heating temperature for nanocrystal TiO2 were studied in detail. Results indicated that: (1) constant of reaction rate decreased and the initial reaction rate increased with the increase of initial concentration of phenol. The possible reason for this might be that the former related to the adsorption ratio of phenol on catalysts while the latter related to the amounts of adsorbed phenol. (2) 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. And the effect of pH on photodegradation efficiency was consistent with the adsorption efficiency. Therefore, we might conclude that the adsorption of phenol on catalysts played an indirect active factor in enhancing the photodegradation reactions. (3) Adding oxide can enhance photodegradation reaction rate. (4) Elevating reaction temperature contributed to the transformation of crystal TiO2 from rutile to anatase. The temperature range for transformation is 450-500C. Best photocatalytic efficiency can be obtained when crystal TiO2 was sintered at 550C and the content of anatase reached 82.75% and particle size was in the range between 30 to100nm. Photodegradation efficiency for phenol is 80.1% on glass-supported TiO2 membrane under the following conditions: initial phenol concentration 80mg/l with proper amount of H2O2 at pH=2 and with high-pressure mercury lamp.In order to increase the pregnant amount of effective catalysts, a kind of porous ceramic was selected as carrier medium. Polymerizing-gelling method was adopted an...
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