Research On Preparation And Application Of Photocatalytic Material Of Metal Doping Nanometer TiO₂/Kaolinite

Among semiconductor photocatalytic materials in recent years, titanium dioxide has been widely used because of many advantages, such as better chemical stability, higher photocatalytic efficiency, cheapness and intoxicity. Titanium dioxide can be used as environmental material to treat polluted water, purify dirty air and kill bacteria etc. Natural nonmetallic mineral is a perfect supporter for titanium dioxide, which can support the film of nanometer titanium dioxide by some way. The photocatalytic efficiency of nanometer titanium dioxide on nonmetallic mineral is sustained and can be reused.In this research, titanium dioxide photocatalyst supported on kaolinite was successfully prepared by sol-gel method. Chemical and heating synthetic doping are adopted to modify the TiO₂/ kaolinite photocatalytic materials. Fe³⁺, Sn⁴⁺ and Zn²⁺ were used to dop the TiO-2/ kaolinite photocatalytic materials, at the same time Fe₂O₃, ZnO and V₂O₅ were used to heat synthetic doping the TiCV kaolinite photocatalytic materials.Modern testing methods to study nanometer titanium dioxide on the surface of kaolinite were also adopted in this study, which are XRD, IR, Raman, XPS and AFM, TEM. It could be seen that titanium dioxide had been loaded on the surface of kaolinite successfully and uniformly. The particle size of titanium dioxide is consisted of 1-10 nanometers. The crystal of titanium dioxide is perfect and ordered. The state of metallic ion and metallic oxid in the TiO₂/ kaolinite photocatalytic materials was also checked, which revealed the possible mechanism of Chemical and heating synthetic doping of the TiO₂/ kaolinite photocatalytic materials.In order to evaluate the photocatalytic activity of TiO₂/ kaolinite, the industry wastewater (AZO-dye) was degraded. The experiment results showed that the two methods improved material photocatalytic activity in some way and the photocatalytic effects were also raised obviously in sunlight..The optimal reaction condition decided by the experiments is that: hydrolysis for 3 hours at 50℃, drying at 70℃, calcinations at 600℃.In the uv-light, with the Fe³⁺ doped dosage of 1.0%, the rate of photocatalytic degradation was 97.6%. With the Sn⁴⁺ doped dosage of 1.5%, the rate of photocatalytic degradation was 97.2%.In the sunlight, the doping of Fe³⁺ made the photocatalytic efficiency enhanced 29.10% and Sn⁴⁺ was 34.04%. The doping of Fe³⁺, Sn⁴⁺ made the photocatalytic effects be enlarged obviously in sunlight.In the some way, photocatalytic activity was improved by heating synthetic doping of Fe₂O₃ and the photocatalytic efficiency were also raised obviously in sunlight.The rate of photocatalytic degradation was 98.8% by the Fe₂O₃ heating synthetic doped dosage of 0.5% in the uv-light and enhanced 38.9% than non-doped. Meanwhile, photocatalytic activity was also increased in a way by heating synthetic doping of ZnO. In this research, the effect of synthetic doping of V₂O₅ was also explored.The reuse of photocatalytic material was also researched in this thesis. The experiment results showed that the material can be reused many times and can be recoveried easily.