The Studies On Preparation And Photocatalytic Activity Of Nanosized TiO₂/Diatomite Composites

Since the1950s, the global atmosphere, water, soil and biology have been varying degrees of pollution, so the governance environment is imminent, because nanometer TiO2is low cost, green environmental protection, and the catalytic degradation of organic pollutants,so it is widely applied. However, TiO2powder have problems such as separation recycling difficulties, low quantum efficiency, so it is restricted in the wide application Diatomaceous earth, it is ancient single-celled diatoms sediments, it has a porous structure, non-toxic and can absorb harmful gas. Diatomaceous earth, moreover, its surface has a lot of silicon hydroxyl groups, so it can capture the light holes very well, and restrain that the photocatalytic electronics-hole pair is compound invalidly, but diatomite can only act as a physical adsorption, it does not degrade dye and toxic gases.Diatomite and TiO2’s coating, on the one hand, can achieve the TiO2immobilization, on the other hand, can adsorbe the organic matte to the surface of TiO2by the mineral adsorption grain size, and increase the catalyst and pollutants’contact, so it can achieve the purpose of improving the degradation rate, so the diatomaceous earth and TiO2composites have become the research focus for the scholars in recent years.At present, the preparation methods of nano-TiO2composite photocatalyst are sol-gel method, coprecipitation, mechanical activation method and so on, however, these preparation methods are expensive, the technology is complicated, and the production efficiency is low, so it is difficult to achieve the large-scale production. Cheap titanium tetrachloride and diatomite are used as material, normal temperature complexation is used as method, nano TiO2/diatomite photocatalyst is prepared. According to the research content, this thesis can be divided into two parts:1. The preparation of nano-TiO2/diatomite composite materials and light catalytic properties. Based on the TiCl4, organic carboxylic acid, NH3-H2O, D-sorbitol, etc as main raw materials, and adopt normal temperature complexation-roasting decomposition to prepare the TiO2/diatomite composites with high performance. It analysis the morphology, surface composition of original diatomite, nanometer TiO2and composite materials by testing method such as SEM, XRD and EDX, and found that the diatomite microporous reduce after the load of the surface, it is calculated that the load on the surface of TiO2grain size is nanoscale, granularity is about10nm and the crystal type is anatase. In the optical intensity of91700uw/cm2, uvintensity of499uw/cm2, composite materials which TiO2and diatomite quality ratio is1:3and are heated in300℃have the light degradation ability, they can decompose50mg/L acid red3R up to94.06%by two hours.2. The nano-TiO2/diatomite composite materials in the application of the coating. Experiments show that the contrast, alkali resistance of coating which mixed composite materials meet the national standard, and the coating has the function of light degradation of organic pollutants, this play a very positive role in solving the problem of air pollution after house is refurbished.