BiOCl/蒙脱土复合光催化剂的制备及其光催化活性

为优化BiOCl光催化剂的结构,改善其对有机污染物的吸附性能,进而提高光催化反应活性,采用超声辅助化学沉淀法制备了BiOCl/蒙脱土(MMT)复合光催化剂,并考察了MMT质量分数(w(MMT))对复合光催化剂结构及光催化反应活性的影响。 X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、傅里叶红外光谱(FTIR)和紫外-可见漫反射光谱(DRS)等的表征结果表明,所得催化剂呈微球状结构,禁带宽度为3.24 eV。 随着w(MMT)的增加,催化剂的微球状结构逐渐被破坏,但带隙能未发生明显变化。 以8-羟基喹啉为目标物考察了复合催化剂的吸附及光催化反应活性。 结果表明,随着w(MMT)增加,催化剂对8-羟基喹啉的吸附和光催化氧化活性逐渐增加,这可归因于与MMT的复合增大了比表面积并降低了光生载流子复合效率。 当w(MMT)为15%时,催化剂的吸附及光催化性能达到最佳,光照50 min后,8-羟基喹啉的降解率达到85.6%,矿化率达到51.0%。 光生空穴和超氧自由基负离子为主要的氧化活性物种。 复合催化剂还可高效降解邻苯二酚和对氨基苯甲酸。 同时,复合光催化剂表现出较强的化学稳定性,表明其具有较强的实际应用价值,可用于处理含有机酚类污染物的工业废水。

Preparation and Photocatalytic Activity of BiOCl/Montmorillonite Composite Photocatalyst

In order to optimize the structure of BiOCl photocatalyst, improve its adsorption performance to organic pollutants, and enhance photocatalytic activity, BiOCl/montmorillonite(MMT) composite photocatalyst was prepared by ultrasonic assisted chemical precipitation method. The influence of composite mass fraction of montmorillonite(w(MMT)) on its photoactivity was investigated. The characterization results of XRD, SEM, FTIR and DRS show that the obtained composite catalyst has a microsphere structure with a band gap of 3.24 eV. With the increase of w(MMT), the microsphere structure of the composite catalyst is gradually destroyed, but the band gap energy does not change significantly. The adsorption and photocatalytic activity of the composite catalyst were investigated with 8-hydroxyquinoline as the target. The results show that with increase of w(MMT), the adsorption and photocatalytic oxidation activity of 8-hydroxyquinoline is gradually increased, which can be attributed to the increased specific surface area and reduced photo-generated carriers' recombination efficiency due to the composite of montmorillonite. When w(MMT) is 15%, the adsorption and photocatalytic performance of the catalyst are optimal. After 50 min of illumination, the degradation rate of 8-hydroxyquinoline reaches 85.6%, and the mineralization rate reaches 51.0%. Photogenerated holes and superoxide radical anions are the main oxidation active species. The composite catalyst also efficiently degrades catechol and p-aminobenzoic acid. At the same time, the composite photocatalyst exhibits strong chemical stability, indicating that it has strong practical application value and can be used for treating industrial wastewater containing organic phenolic pollutants.