| A lot of research works have focused on understanding the fundamental processes and on enhancing the photocatalytic efficiency of semiconductor catalysts since A. Fujishima and K. Honda reported the photoelectrochemical water-splitting by TiO2 electrodes in 1972. The technique of photocatalytic oxidation which utilizes a semiconductor as catalyst is a new kind of water treatment process with great potential application in water treatment for its good ability to utilize natural resource, solar energy, and its outstanding effect on degradation of organic substances.However, the use of conventional photocatalyst that is typically delegated by titanium dioxide results in disadvantages of low quanta efficiency and of separation after the reaction, which confined the industrial application. And different methods including surface of TiO2, support, deposition of heavy metals, the compounded semiconductors, the rare elements mixed into TiO2 were studied abroad and at home.The aim of this dissertation is to initiate the research of the synthesis conditions of photocatalysts based on titania pillared clays rectorite (TiO2/R) and the decolorization of Acid Red 3B (ARB) aqueous solution and seek after optimal condition and general degradation rules, by which we look forward to building up the base for further research.In this study, photocatalysts based on TiO2/R have been synthesized by using a commercial rectorite and a reaction mixture containing titanium tetrachloride. Different factors, including temperature of reaction, heat treatment, etc that influence the photocatalytic activity of samples were discussed in detail and the mechanism was explained primarily, also the optimal synthesis condition was concluded.The resultant TiO2/R were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM)and the photocatalytic activity of the photocatalysts was evaluated by the decolorization of ARB aqueous solution. It can be seen from XRD, TEM, etc. that titanium dioxide were incorporated, and the higher the calcining temperature, the more clearly crystalline structure of the samples presented, and rutile and anatase TiO2 have been present when the samples were cacined at the temperature 500 C. Different methods have been found to have different effects on the photocatalytic efficiency of the resultant catalysts for the decolorization of ARB in water. It can be concluded that a 500 C calcining temperature, a 60 C synthesis temperature, a HCl/Ti molar ratio in the range of 1.0-2.0, a proper Ti/rectorite (mmol/g) ratio in the range of 15-25, a slower speed of addition of the pillaring solution to the rectorite suspension, and a sparse clay suspension concentration would be the optimal conditions for the preparation of TiOa-CLR sample.Using the samples synthesized as photocatalysts, the effects of ARB initial concentration, catalyst quantity, light source, solution pH on decolorization ratio were further discussed. The kinetics of photocatalytic oxidation of ARB was also studied.For comparing, the preparation of TiO2-CLR samples and their photocatalytic activity were also studied under different conditions using Ti(OC4H9)4 as precursor and C2H5OH as solvent.
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