Study On Preparation Of Magnetic TiO₂/Fe₃O₄ Photocatalyst And Treatment Of Trichloroethylene In Water

Trichloroethylene is carcinogenic chloride and diffcult to degrade. Traditional processes of trichloroethylene have its limitation. Photocatalytic oxidation process has become a focus of the removal of toxic pollutants diffcult to degrade. It has the advantage of normal temperature and atmospheric pressure operation, less energy cost, high efficiency degradation of pollutants. In addition, the use of aqueous suspensions limits practicl applications because of problems of the separation and recycling of fine particles of TiO₂. In this paper, magnetic TiO₂/Fe₃O₄ photocatalyst was prepared by Sol-gel method and using magnetic Fe₃O₄ as carrier. The prepared catalysts were characterized by XRD, IR, SEM and BET methods. The catalytic activity of prepared catalyst was evaluated by using trichloroethylene as model pollutant in Photocatalytic oxidation process. The recycle percentage and service life of magnetic TiO₂/Fe₃O₄ photocatalyst were investigated. At last, the mechanism of photocatalytic degradation trichloroethylene has researched.The results showed that the removal rate of trichloroethylene was low in the presence of TiO₂ or UV light alone, and effect of trichloroethylene degradation was better when both UV light and TiO₂ were employed together. Optimum reaction condition of TiO₂ photocatalytic degradation trichloroethylene was that trichloroethylene removal could attaind to 95.17% after 1h with 0.05g/L concentration of TiO₂, pH=7.0, 8mg/L dissolved oxygen and 10mg/L initial trichloroethylene concentration. The kinetics of degradation of trichloroethylene in the condition of different catalyst amount and initial concentration were investigated. The result followed the first-order kinetic law.The prepared parameters were optimized and the results showed that the catalyst with Ti:Fe(mass ratio)=1:1 at calcination temperature 500℃for 3 hours has the highest catalytic activity. TiO₂ was coated on the carrier Fe₃O₄ and was anatase. The size of magnetic TiO₂/Fe₃O₄ photocatalyst was adout 43.6nm. Compared with TiO₂, the surface area, pore volume and pore size of magnetic TiO₂/Fe₃O₄ photocatalyst was small due to increasing the size of magnetic TiO₂/Fe₃O₄ photocatalyst.Photocatalytic activity of magnetic TiO₂/Fe₃O₄ photocatalyst was studied. Trichloroethylene removal could attaind to 88.76% after 1h with 0.1g/L concentration of TiO₂/Fe₃O₄, pH=7.0, 40ml/min air flowrate and 10mg/L initial trichloroethylene concentration. Magnetic photocatalyst could be separated and recovered, and recovery was high. It had a relatively high activity after temary cycle, and recovery after recycle utilization was also high.Finally, the mechanism of photocatalytic degrading trichloroethylene has been researched. Final products were CO₂ and HCl.