The Study On The Preparation Of TiO₂/Mineral And Photocatalytic Degradation Of Methyl Orange

Nanometer TiO2 has the following properties: safety, innocuity, low-cost and no secondary pollution, and it also has the functions of antibiosis and antisepsis. It is one of the photocatalyst of new pattern and the inorganic antisepsis with the most efficiency. Now, the preparation of nanometer TiO2 is mainly via liquid phase methods. Aiming at the problems of reducing cost, increasing the separation efficiency of the solid and liquid, and improving the disperse rate and the photocatalytic effect of nano-TiO2 when synthesizing in liquid phase, this dissertation, taking the natural minerals as carrier and the industrial metatitanic acid and the industrial black titanic liquid as the raw material, has studied the selection of the nature mineral, the methods and the conditions of the preparation of TiO2/mineral with nano-structure and the photocatalysis of the product.By being compared the adsorbent rate to TiO2, the minerals (diatomite, sepiolite, vermiculite, grammite, kaoline, bentonite) has selected elementarily in the paper. And the effects of ballmilling, floatation and weight-selection, acid treatment and heat treatment on the specific surface and adsorbability of the natural minerals have been studied further, especially on diatomite and sepiolite.About the preparation of the material, this dissertation stared with the preparation of TiOSO4, and, taking the diatomite as the carrier, has studied the four preparationmethods: neutralizing hydrolysis, homogeneous precipitation, forced hydrolysis under boiling reflux conditions and titanium peroxide sol method. In this dissertation, the synthesized conditions, such as the initial concentration of Ti4+, the initial acidity, the reactive temperature and the reactive time, have been studied with their effects on the photochemical activity of the product and the four preparation methods have been compared and optimized. In the last of this chapter, the study of the extension preparation on the scale of kilogram in laboratory has been carried out.In order to study the photochemical activity of the product further, this dissertation, taking methyl orange as a deputy of organism, has studied the relation between the concentration of the organism and the reactive time during the process of light degradation, and, on the basis of the relation, the kinetic process of the photocatalytic degradation was achieved by the treatment on the curve of the organism concentration to the reactive time: zero order reaction of the high organism concentration, first order reaction of the middle organism concentration, second order reaction of the low organism concentration. In addition, the paper has studied and compared the reactive conditions' effects on the efficiency of the photocatalytic degradation, such as the pH value and the reactive temperature.