Study Of The Preparation And Application Of TiO₂/Diatomite Complex Photocatalyst

Diatomite is an excellent porous sorbent with low price. It has good adsorption of almost all the organic pollutants in the water. With the merits of good photocatalyzing activity, good stability and innocuity, TiO₂ has become a kind of semiconductor material with much attention in the field of photocatalysis. As there are a great deal of hydroxyl groups on the surface of diatomite, so the complex photocatalyst prepared by the diatomite and TiO₂ can capture the photogenerated holes, and restrain the useless combination of the electron-hole pairs. On the other hand, the complex photocatalyst can absorb the organic pollutants to the surface of TiO₂ by its adsorption, and increase the probability of the contact between catalyst and pollutants, then get the purpose of increasing the efficiency and the rate of photo-degradation.Using the original diatomite in Sichuan Miyi as the raw material, based on the thermodynamics analysis, this paper purifies the diatomite by the physical-chemical combining method. In the physical treatment, the effect of scrubbing concentration, scrubbing time, dosage of dispersant, sedimentation time, scrubbing times are all considered. While in the chemical treatment, the effect of acid washing time, acid concentration, acid washing temperature, baking time and temperature are considered and examined. For the first time, by using the hydrolyzationof titanium sulfate, the Ti02-diatomite complex photocatalyst is prepared via the simple and convenient impregnation method.After the systemic study for the preparation conditions of the complex photocatalfst, the result is the complex photoeatalyst with good effect can be prepared in the room temperature, and it has not only good adorption, but also high ultraviolet photocatalytic activity for the methylene blue solution. This complex photocatalyst has the characteristics of low price, easy operation and good effect, so it has good practice value and application prospect.Waste acid water produced by the hydrometallurgy of some plant is applied to treat the diatomite. The experiment shows that it has certain effect for purification of the diatomite, and the method can avoid the problems of large amount of acid, the second pollution, etc.