蛋白石页岩表面处理对负载TiO_2结构与性能的影响

Influence of Opal Shale surface Treatment on the Structure and Properties of TiO_2 Loaded on Opal Shale

以蛋白石页岩为载体,钛酸四丁酯为钛源,采用溶胶凝胶法制备了TiO_2/蛋白石页岩光催化复合材料。采用TG-DTA、XRD、FT-IR等测试手段对其进行了表征分析,以甲基橙为目标降解物对其光催化活性进了研究。结果表明:经过酸处理的蛋白石页岩有利于提高其负载的TiO_2的热稳定性,其中经过H_2SO_4处理的蛋白石页岩对其负载的TiO_2晶型转变的抑制作用更明显;负载的TiO_2与蛋白石页岩没有发生化学键合,只是以物理包裹的形式相结合;不同处理方式的蛋白石页岩在负载TiO_2后,其晶粒尺寸有明显的差别。本试验中,经过H_3PO_4处理的样品的光催化性能最好,在紫外光照射下,加入量为0.01 g时,光催化150 min后对浓度为20 mg/L的甲基橙溶液的去除率达90%;在可见光照射下,光催化8 h后对浓度为20 mg/L的甲基橙溶液的去除率可达84.6%,溶液pH值增大,光催化活性增高,无机阴离子的加入有利于光催化反应速率的提高,但是过多的阴离子反而会对光催化反应速率产生抑制作用。

The TiO_2 opal shale photocatalytic composites were prepared by sol-gel method with opal shale as the carrier and tetrabutyl titanate as the titanium source. The samples have been characterized by TG-DTA,XRD and FT-IR. The photocatalytic activity of the samples was studied using degradation of methyl orange. The results showed that after acid treatment the opal shale was conducive to improve the thermal stability of the loaded TiO_2, and among the acids the inhibitory effect of H_2SO_4 treated opal shale on the crystal change of the loaded TiO_2 was more obvious, and the loaded TiO_2 was not chemically bonded with opal shale, but bonded only by physical coating. After loading TiO_2 on opal shale treated by different processing methods, there was obvious difference in the crystal grain size. In this experiment, the photocatalytic performance of the sample treated by H_3PO_4 was the best. Under UV irradiation, with the photocatalyst dosage of 0.01 g, photocatalysis time of 180 min, the removal rate of methyl orange solution with the concentration of 20 mg/L was 90%. Under visible light irradiation, with the photocatalysis time of 8 h, the removal rate of methyl orange solution with the concentration of 20 mg/L was 84.6%. With increasing pH of the solution the photocatalytic activity increased, and the addition of inorganic anions was beneficial to the improvement of the photocatalytic reaction rate, but too many anions could produce a negative effect.