纳米TiO2光催化氧化降解甲基橙动力学研究

Study on the kinetic of TiO_2 photocatalytic degradation of Methyl Orange

以钛酸四丁酯为前驱体、聚乙二醇为模板剂,用溶胶-凝胶法合成了粒径分布均匀的纳米TiO2;用X射线衍射(XRD)、透射电镜(TEM)等对产物进行了表征.以高压汞灯为光源,研究了甲基橙在TiO2水悬浮液中的降解动力学.结果表明,所制备的纳米TiO2为锐钛型结构,粒径为15～20 nm,分布均匀.甲基橙的光催化降解动力学符合Langmiur-Hinshelwood动力学模型,反应速率常数k=0.43 mg/(L.min),表观吸附平衡常数K=0.037 L/mg,其半衰期随着甲基橙初始质量浓度ρ0的增加而延长.

Nanometer TiO2 with level particle size distribution was synthesized by sol-gel method using tetrabutyl orthotitanate as precursor, polyethylene glycol as a template structure-directing agent. The product was characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM）. The kinetic of degradation of Methyl Qrange in TiO2 aqueous suspension was studied using high pressure mercury vapour lamp as illuminating source. The results indicated that the prepared TiO2 was of anatase phase structure with a uniform particle size distribution of 15-20 nm. The kinetic of the degradation of methyl orange accords with the Langmiur-Hinshelwood model, in which the reaction rate constant k=0.43 mg/（L.min）, the apparent adsorption equilibrium constant K= 0.037 L/mg, and the half life increased with the initial concentrations increasing.