Study On Preparation And Properties Of Iron Doped-TiO₂ Photocatalyst

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. However powdered TiO₂ has some shortages such as low catalytic activity, difficulty in separation and recovery. Key problem in this research is modification of TiO₂ and immobilization technology.In this paper,the methods of preparing Fe-TiO₂ thin film coated on glass-slide were investigated. It is suggested that sol-gel method using Ti(OC4H9)4 is the best method for preparation of TiO₂. Wastewater of azo dye was photodegraded by the photocatalyst TiO₂ and the optimal technique condition was obtained. Experimental results were characterized and analyzed by some modern measurements,such as UV-Vis,XRD,Raman,TG-DSC,HRTEM et al.The optimal reaction condition was gotten after experiments and analysis: n=Ti(OC4H9)4:C2H5OH:HNO3:H2O=0.05:15:0.35:2 (mol ratio),hydrolysis at 40℃, W (Fe3+/ TiO₂)=2.5%(mol ratio) ,calcinations at 400℃for 2 hours.On this basis,using ultraviolet germicidal lamp with wavelength of 273nm or vis-light as light-source,the contaminants removal effect in azo-dye wastewater.Under UV irradiation, photocatalytic results of azo dye by TiO₂ compound photocatalyst showed that when initial concentration of azo-dye was A=0.104,solution pH was 4, decolorization rate after 2h could get to 94.7%. COD removal rate Could get to 85.2%.Nevertheless,under solar irradiation,removal rate of azo-dye by TiO₂ compound photocatalyst could get to 53%.The experiment results showed that photocatalytic activity was improved by sol-gel method by doping of Fe3+ and the photocatalytic efficiency were also raised obviously in sunlight. The addition of appropriate amount of Fe3+ is effective for improving the photo-catalytic activities of TiO₂ by inhibiting the formation of recombination centers of photo-generated electron-hole pairs on the surface of TiO₂ particles.The reuse of photocatalytic material was also researched in this thesis. The experiment results showed that the material can be reused many times. The photocatalyst could be recycled several times and removal rate could get to 66.9% after reused 5 times.