BiOCl/TiO2/蒙脱石复合材料对模拟刚果红废水的光催化降解研究

为了解决TiO₂易团聚、带隙宽的问题，提高其对刚果红（CR）的光催化降解率，采用水解法和溶胶-凝胶法制备出BiOCl/TiO₂/蒙脱石复合材料（BCTM），以刚果红染料为目标降解物，进行了光催化试验，研究了溶胶pH、蒙脱石悬浮液质量浓度、焙烧温度、焙烧时间和Bi/Ti摩尔比对复合材料光催化活性的影响，并利用X射线衍射仪（XRD）和紫外可见漫反射仪（UV-Vis DRS）对其进行了表征。结果表明，在溶胶pH为4、蒙脱石悬浮液质量浓度为1%、焙烧温度为600℃、焙烧时间为2 h、Bi/Ti摩尔比为20%的条件下，制备的BiOCl/TiO₂/蒙脱石复合材料具有较高的光催化活性，刚果红的去除率达到了94.04%。复合材料TiO₂以锐钛矿晶相形式存在。添加蒙脱石和BiOCl都会抑制TiO₂晶体的生长。BiOCl/TiO₂之间形成异质结使得禁带宽度从2.89 eV降低至2.61 eV，增强了复合材料对光的吸收能力。 

Photocatalytic Degradation of Simulated Congo Red Wastewater by BiOCl/TiO2/Montmorillonite Composites

In order to solve the problem of easy agglomeration of TiO₂ and wide band gap, and improve the photocatalytic degradation rate of Congo Red (CR). BiOCl/TiO₂/montmorillonite composites were prepared by hydrolysis and sol-gel methods. Photocatalytic experiments were carried out with Congo Red dye as the target degradation product. The effects of sol pH, mass concentration of montmorillonite suspension, roasting temperature, roasting time and Bi/Ti molar ratio on the photocatalytic activity of the composites were studied, and the composites were characterized by X-ray diffractometer (XRD) and Ultraviolet-visible diffuse reflection spectrum (UV-Vis DRS). The results showed that the BiOCl/TiO₂/montmorillonite composite had high photocatalytic activity when the the pH of the sol was 4, the mass concentration of the montmorillonite suspension was 1%, the roasting temperature was 600℃, the roasting time was 2 h, and the molar ratio of Bi/Ti was 20%. The removal rate of Congo Red reached 94.04%. The composite TiO₂ exists in the form of anatase crystal phase. The addition of both montmorillonite and BiOCl inhibited the growth of TiO₂ crystals. The formation of heterojunction between BiOCl/TiO₂ reduced the band gap from 2.89 eV to 2.61 eV, which enhanced the light absorption capacity of composites.