Study On The Preparation, Characterization And Activity Of TiO₂ Photocatalyst

With the advancement and development of modern industry, increasing environmental problems are brought out. There are many methods for disposing contaminations, among which the multiphase photocatalysis for the degradation of contaminations of nano TiO2 is superior. This method has high activity, no selectivity, complete oxidation, sunlight and oxygen's application (in water phase). It can be applied for hard degradation. American, Japan and Canada use the technology of TiO2 photocatalysis for environmental protection. But now, the research level of this technology is limited in the laboratories in China. This thesis includes three parts of work:the preparation of TiO2 nano crystals, the immobilization of TiO2 films and the research of the photo catalytic activity. The TiO2 nanoparticles are prepared in water/ OP-7 / heptane micro emulsions, which are characterized by TG-DTA,DSC,XRD,FTIR,TEM and BET. Compared with water/Span-80/cyclohexane micro emulsions and Sol-gel methods, its product process ,washing, solvents reclaim and yield are advantageous. Results showed little solvents residue and a crystalline transform temperature of 437.3 ℃. The TiO2 nanoparticles have uniform size distribution with the average particle size in the range of 9.7～15.8 nm, and relative large specific area. The yield of this method is 80%.The TiO2 films are immobilized on the actived carbon and holographic glasses by liquid phase deposition at low temperature, which are characterized by microscope, SEM and SPM. Compared with common liquid phase deposition and Sol-Gel method, there are no flaws and holes on the films, whose surface are plane. The SPM showed the films have the structure of islands and the average size of second particles are 10 nm. The TiO2 nanoparticles have uniform size distribution. This method reduces the reunite. The phenol is used as the model of photocatalytic reaction. The photocatalytic activity of different methods and sizes are investigated in the phenol solution. The mechanism of phenol degradation are studied. Results showed the photocatalytic activity has inverse proportion with the particle size. The photocatalytic activity is higher by micro emulsion method. The degradation of phenol reaches to 80% in 3 hours with the particle size of 6.5nm. The TiO2 photocatalysts can be regenerated after reaction.