改性纳米TiO_2降解水中微量次甲基蓝的动力学研究

Kinetic Mechanism of Photo-catalytic Oxidation for Soluble Methylene Blue in Water by SO_4^(2-)Modified Nano-sized TiO_2

以四氯化钛、硫酸铵为主要原料,采用溶胶-凝胶法制备了SO42-/TiO2光催化剂,用XRD、FTIR进行了表征,并将其用于光催化降解水中微量次甲基蓝溶液。实验表明,SO42-离子的掺杂修饰,使纳米TiO2结构明显改善。次甲基蓝溶液初始质量浓度在6~15 mg/L的范围内,其光催化降解反应遵循表观一级反应动力学规律。反应的表观速率常数随着溶液初始浓度的增大而减小,半衰期随溶液初始浓度的增大而增加。

Nano-sized SO2-/TiO2 particles were prepared from TiC14and （NH4）2SO4 by the Sol-Gel method and characterized by XRD and FTIR. Photocatalytic degradation of methylene blue solution under ultraviolet radiation was carried out by using nanoparticle TiO2 doped with SO4^2- as the photocatalyst. It was found that doping of SO4^2- into TiO2 by the Sol-Gel method remarkably improved its structure. The reaction of photo-catalysis for methylene blue is in conformity with the first order kinetic law in appearance within the concentration range between 6 mg/L and 15 mg/L. The appearance rate constant of the reaction decreases and the half-life period of the reaction increases with increasing of initial concentration of methylene blue in water, respectively.