Study On Preparation And Characterization Of TiO₂-coated Palygorskite

Photocatalytic oxidation of watercontaminants is a new type of method for wastewater treatment. It is widely and deeply studied by many people for its high photodegradation eficeiency, none secondary pollution caused . 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.In this study, photocatalysts based on TiO₂/Palygorskite have been synthesized by using Palygorskite and Tetrabutyl Titanate. 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/Palygorskite were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and the photocatal activity of the photocatalysts was evaluated by the decolorization of Acid Red GR aqueous solution. It can be seen from XRD, TEM, etc. that titanium dioxide were in corporate, and the higher the calcining temperature, the more clearly crystalline structure of the samples presented. Different methods have been found to have different effects on the photocatalytic efficiency of the resultant catalysts for the decolorization of ARGR in water. It can be concluded that a 700℃ calcining temperature, a 40% /Palygorskite and a 2 h calcining time.Using the samples of TiO2-coated Palygorskite synthesized as photocatalysts, the effects of ARGR initial concentration, catalyst quantity, solution pH on decolorization ratio were further discussed. The kinetics of photocatalytic oxidation of ARGR was alsostudied. It can be concluded the removal rate reaches the highest under the conditions of the amount of TiO₂-coated palygorskite catalyst at 0.25g/L, pH at 1.