LDO负载纳米二氧化钛复合物的制备及其光催化性能研究

以碳酸根型镁铝层状双氢氧化物(LDH)为载体,采用溶胶-凝胶法利用酞酸丁酯水解负载纳米TiO2于LDH片层获得TiO2/LDH前驱体,通过低温焙烧前驱体获得纳米二氧化钛/层状双金属氧化物复合物(TiO2/LDO).以亚甲基蓝溶液模拟染料污染物,在波长291 nm紫外光条件下测定吸光度,评价了光催化剂不同投加量,体系pH值以及光照时间条件下对亚甲基蓝降解率的影响,研究了TiO2/LDO的光催化性能.结果表明:通过溶胶-凝胶法可以获得高分散纳米级(<10 nm)TiO2负载型TiO2/LDH复合物,TiO2/LDH中TiO2负载率达8.01wt%(质量分数);TiO2/LDO的光催化性能较纯LDO高,TiO2负载于LDO层板对亚甲基蓝具有协同催化作用;在pH值为9的80 mL亚甲基蓝溶液(浓度为5 mg/L)中投入0.20 g TiO2/LDO,催化反应8 h后降解率高达81.7%,TiO2/LDO对亚甲基蓝溶液的光催化反应符合一级动力学方程.

Preparation and Photocatalytic Properties of Nano TiO2 Loaded on Layered Double Oxides

Basing on the carrier of MgAl-CO3-LDH and the hydrolysis of tetra-n-butyl titanate,TiO2/layered double hydroxide (TiO2/LDH )was prepared by loading nano TiO2 on LDH layers via sol-gel method. Photocatalyst of TiO2/LDO was obtained by calcination TiO2/LDH. Influences of dosage of TiO2/LDO,pH and illumination time on photocatalytic properties were studied by photocatalytic degradation of the simulated dye pollutants of methylene blue solution under UV light (λ =291 nm ) irradiation. The results indicate that dispersity of nano TiO2 (<10 nm)can be improved by sol-gel method. The weight loading amout of TiO2 on LDH was about 8. 01wt%(in weight)in TiO2/LDH. The photocatalytic property of TiO2/LDO is higher than that of LDO. The loading TiO2 and the LDO layers have a synergistic photocatalytic effect on degradation of methylene blue. When 0. 20 g TiO2/LDO was added in the 80 mL methylene blue solution(pH=9)at concentration of 5 mg/L for 8 h,the degradation rate of methylene blue reached 81. 7%. The photocatalytic reaction of TiO2/LDO on methylene blue coincides with the first order kinetics equation.