Of Tio <sub> 2 </ Sub> Nanocomposite Powder Preparation And Uv Shielding And Photocatalytic Performance Study

This study mainly prepared nano-composite powders based on TiO₂, and the obtained samples were characterized by XRD,TG-DTA,TEM and so on. The UV-shielding capability and photocatalysis oxidation technology of composite powders was studied. The main work was summrazied in the following:1) The surface of rutile nano-TiO₂ was coated by ZnO through chemical deposition to prepare TiO₂/ZnO nano-composite powders. The obtained samples were characterized by XRD,TG-DTA,FT-IR,TEM,color difference analysis,UV-Vis Diffusion Reflectance Spectroscopy. The effects of reaction conditions such as precipitator, reaction temperature, calcining temperature and calcining time on the microstructure of nano-composite powders were investigated. The suitable conditions for the preparation were given : when the (NH₄)₂CO₃ agent used as precipitation, m(ZnO):m(TiO₂)=1:1,the reaction temperature was 80℃, the calcining temperature was 400℃, the calcining time was 2h. The nano-composite powders have a good UV-shielding capability.2) The surface of TiO₂/ZnO nano-composite powders was modified with silane (LM-N308) as crosslinking reagent in distilled water. The products were studied by means of FT-IR, TG-DTA and HRTEM. The effect of pH value, hydrolysis temperature, the covering ratio of silane coupling agent, and reaction time on organic surface modification with TiO₂/ ZnO were investigated . Both FT-IR and HRTEM results confirmed that LM-N308 was found on the surface of nanosized TiO₂/ZnO particles and an organic coating layer was formed. The weting and dispersivity experiment showed that the surface property of nanosized TiO₂/ZnO modified with LM-N308 was changed from hydrophilicity to lipophilicity. Ultraviolet-visible reflecting diffuser spectrometry confirmed that the surface organic modification could weaken ultraviolet shielding function of TiO₂/ZnO nano-composite powders.3) The nano-attapulgite(ATP) was coated with nano-TiO₂ by chemical coprecipitation using attapulgite and TiCl₄ as precursor, then using different heat treatment to prepare nano TiO₂/ATP. Using methylorange as organic waste water, phototalytic degration rate of methylorange by TiO₂/ATP was investigated. The samples was characterized by XRD, TEM techniques. Results showed that the sample prepared by low-temperature coprecipitation method have a good phototalytic degration ability. The suitable conditions for preparation were ascertained as: m(TiO₂):m(ATP) =100%; adding ATP temperature, 60℃; adding material method, special dripping, and there are two phases in the sample, which contains anatase mainly and a small amount of rutile. The phototalytic degration rate of sample treated by hydrothermal method is worse than that by low-temperature coprecipitation method, TEM showed the cause is particles aggregating. The sample treated by calcination have the least phototalytic degration ability because the particles aggregate is most serious.