The Study On Preparation, Characterisation And Properties Of TiO₂-Diatomite Nanocomposite

Since Honda and Fujishima in1972reported on a titanium dioxide electrode （TiO₂）photocatalytic water splitting phenomenon has been represented, with nanometer TiO₂as therepresentative of the photocatalytic semiconductor material, due to its good dielectricproperties, catalytic activity and good stability, cheap and non-toxic and subjected to chemical,material, environment, construction and other areas of concern and research. Nanometer TiO₂as a photocatalyst, in whose size is smaller than10nm, because of the quantum effects andhave significant light catalytic characteristic, this kind of activity is very suitable for theoxidative degradation of organic pollutants present in the building, functional coatings, selfcleaning materials, solar cells,cosmetic sunscreen products manufacturing, medicalsterilization and treatment of industrial waste water of life there is extensive use.Used for light catalyst carrier in addition to should have a general catalyst carrierrequested cheap, stable, large specific surface area, high material strength and is not easy tocorrode,still need to make the load on the carrier of photocatalyst as much as possible bylightactivation and the play of light catalytic effect. Diatomaceous earth has an excellent porestructure, size micron level, the linear hole and shell stitch are within nano level, is a naturalnanometer materials, diatomite special pore structure and morphology determine its effect andsurface with a porecharge effect, and has a good filtration, adsorption, ion exchange, and otherphysical and chemical properties of the carrier function, which is a good carrier classfunctionality TiO₂photocatalyst materials. As the polar and hydrophilic TiO₂surface withsparse oil, in organic media pool and easy to produce precipitation, direct impact on thecatalytic efficiency,TiO₂photocatalytic activity and adsorption properties of diatomitecombination, can enhance the diatomite purification ability and the life span but also enhancethe photocatalytic reaction rate, by nano-TiO₂load, which you can protect, release,long-lasting effect, made of nano-TiO₂/diatomite composite materials, can be widelyappliedto wastewater treatment, air purification, antibacterial and multifunctional materials（Temperature, humidity, noise） etc.This thesis is based on the content of the study is divided into the following sections:A. Select from the carrier, the synthesis of mechanisms and methods, mechanisms,doping modification, materials and applications to explore the status and progress ofsupported TiO₂nanoparticles provides a theoretical basis for the experiment. B. TiCl4and diatomaceous earth as raw material, liquid phase deposition methodprepared by the mixed crystal composite of nano-TiO₂and Diatomite, The effects of differentpH conditions as well as raw materials in the preparation process the amount of theperformance of the composite, to determine the optimal pH value and solid load. The resultsshow that, under conditions of pH9, TiO₂loading for the quality of33.3%（TiO₂anddiatomite composite ratio of1:2） photocatalytic degradation of formaldehyde with the bestcatalytic activity. And preparation of materials by SEM, TEM, XRD, IR, and a series ofcharacterization, to determine the structure of the material prepared. The load structure showthat the improved surface area and photocatalytic activity of TiO₂nano diatomite surface areaand porous structure, the composite catalyst significantly increased the degradation rate of dye.The composite materials used in the degradation of acid scarlet3R experiments to study thecatalyst preparation process and the factors affecting the photocatalytic process, explore itsphotocatalytic mechanism and reaction kinetics.C. TiCl4, Ti （OBu） and diatomaceous earth as raw material, liquid deposition and sol-gelmethod, respectively TiO₂Nano in the diatomite. Within the range of pH value of7-10, usingdifferent TiO₂doped and sintered at different temperatures of samples prepared using of SEM,and XRD to characterize the surface morphology and composition of the raw materials andcomposites, and explores the different preparation conditions Immobilization rate andphotocatalytic activity of TiO₂diatomite composite material, and samples for quantitativeanalysis and photodegradation of acid Red3R series of experiments. The test results show thatthe product prepared composites in purity, the photocatalytic performance, recoveryrate, yield,and economy better than the sol-gel prepared by liquid deposition method. Products obtainedin the mass ratio of TiO₂and diatomite3:4have best immobilized rates.