复合催化剂SO42--H3PW12O40/TiO2(P123)的制备及其光催化降解二硝基甲苯

 采用溶胶-凝胶与溶剂热相结合的方法制备了系列介孔复合光催化剂SO₄^2--H₃PW₁₂O₄₀/TiO₂ （P123），并对其进行了表征和分析。N₂吸附表面分析及扫描电镜（SEM）图片显示，复合催化剂的粒径明显减小，比表面积高达211m²/g，是TiO₂的5 倍。紫外漫反射吸收光谱（UV-Vis）显示，与TiO₂相比，复合催化剂的吸收光谱发生了明显的红移，且吸收强度明显增强。运用L₁₆（4⁵）的正交实验设计探讨了H₃PW₁₂O₄₀负载量、模板剂P123 的添加量、溶液初始pH 值、催化剂加入量以及H₂SO₄浓度5 个因素对二硝基甲苯（DNT）降解性能的影响，并对正交实验结果进行了直观分析和方差分析。结果表明，该降解过程符合L-H 表观一级反应动力学，在催化剂用量为1.2g/L、H₃PW₁₂O₄₀负载量为20%、模板剂P123 的加入量为2g、溶液初始pH 为2、H₂SO₄的浓度为1mol/L 条件下，经氙灯光源辐照4h 后，DNT 的降解率达到98.7%，DNT 降解的半衰期为0.7162h，取得了良好的光催化效果。

Preparation of SO42--H3PW12O40/TiO2(P123) and It’s Photocatalytic Activity for Dinitrotoluene Decomposition

Mesoporous materials SO₄^2--H₃PW₁₂O₄₀ /TiO₂(P123)were synthesized by combining sol-gel technology and solvothermal treatment. Nitrogen adsorption-desorption analysis and Scanning Electron Microscopy (SEM) results suggest that the specific surface area of SO₄^2--H₃PW₁₂O₄₀ /TiO₂(2gP123)is 211m²/g, which is five times higher than that of pure TiO₂. The average particle size of composite catalyst decreases obviously. Results of ultraviolet-visible absorption spectra (UV-Vis) show that, compared with pure TiO₂, an obvious redshift of composite catalysts was observed and the absorption intensity of the band increased significantly. By means of the orthogonal design method of L₁₆(4⁵), the influence of various operating parameters on the dinitrotoluene (DNT) degradation were investigated, including H₃PW₁₂O₄₀ loadings, dosage of template agent P123, initial pH value of the solution, catalyst dosage and the concentration of H₂SO₄, then the intuitionistic analysis and variance analysis were performed. Kinetics results show that the photocatalytic degradation of DNT fits the apparent first-order reaction. The conversion of DNT reached 98.7% after xenon lamp irradiating for 4h under optimum operating conditions: 1.2g/L catalyst dosage, 20%H₃PW₁₂O₄₀ loading, 2g dosage of P123, pH value 2 and 1mol/L H₂SO₄. The half-life of DNT degradation is 0.7162h. The experimental results demonstrate that the photocatalytic effect is good.