| The deterioration of environment,especially the atmosphere pollution, resulting from the increasing and developing of industrialization, has become one of the city's environment protection problems which is in need of earnestly solving.With its renewal ability and storability of energy and friendliness of environment, nano-semiconductor TiO2 is the very novel green purificant.Now its relevant study becomes the focus of the field of photocatalysis, especially in exhaust gas treatment. In this paper, dispersion of nano-particles in water was mainly investigated, and photocatalysis air-purifying coatings containing nanometer TiO2 photocatalyst were prepared, their performances were tested.Such factors as category and content of dispersant, pH, disperse manner and disperse time, has effect on the stability of nano-TiO2 aqueous dispersion. The stability of dispersion has been in token of spectrophotometer and laser particle-sizer. It is proved that when condition is dispersant A =1%, pH =10, particle content = 5%(wt%), mixing around under high speed for two hours, excellent stable nano-TiO2 aqueous dispersion can be acquired. In addition, the stability of nano-Ti02 solvent dispersion is discussed.In this paper, nanocomposite photocatalytic coatings have been prepared by use of photocatalytic property of nano-TiO2. By water contact angle meter, photocatalytic ability of several kinds or crystal form of TiO2 has been compared. In addition, OH and OH~ have been proved to be in existence on coating surface by FTIR.The effect of illumination time, nano-TiO2 content in the coating, initial concentration of formaldehyde etc.on the photodegradation efficiency on HCHO were disscussed. The effect of nano-TiO2 amount on viscosity, hardness and other applied performance of the coatings we prepared were discussed. Solvent-based photocatalysis air-purifying coatings containing nanometer TiO2 photocatalyst using fluororesin and silicone resin were prepared. When the particle content of nano-TiO2 is 46wt%(namely pigment binder ratio is 3:7), degradation rate of the coating onHCHO after 4 hours is average 55.2%. Particles size of nano-TiO2 in the coatings is mainly around 100nm testing by SEM photo, and the basic performance of this kind of solvent-based photocatalysis air-purifying coating containing nanometer TiO2 photocatalyst accorded with or excel correlative national standard. |
