CX-(TiO2(0.1)La(x))制备及可见光催化降解多环芳烃增溶废水

Preparation of CX-(TiO2(0.1)La(x)) composite and visible light photocatalytic degradation of polycyclic aromatic solubilized wastewater

摘要:

采用溶胶-凝胶法制备甲醛-间苯二酚-间苯三酚碳干凝胶(CX)，再掺杂金属元素镧改性TiO2，制备系列复合材料CX-TiO2-La(x)（x取值为0.05、0.5和8），并用于在可见光下处理模拟土壤淋洗（增溶）废水。通过XRD、TEM、SEM、FTIR等对材料的结构与性能进行表征。结果表明，该复合材料可实现对增溶污染物的吸附富集和高效催化降解，晶体组成主要为无定形碳、金红石型TiO2和La2Ti2O7。“富集-降解”协同作用下，当氯化镧添加量为0.5%时，CX-TiO2-La(0.5)对增溶的菲(PHE)的移除率最佳，达到83.6%（500 W的氙灯照射5 h）。复合材料为介孔材料，增溶PHE的吸附过程复合二级动力学模型和Langmuir模型拟合良好，且为自发化学吸附过程。推测材料内部形成了La2Ti2O7-CX-TiO2异质结结构，扩大了TiO2的光催化相应范围，使其在可见光下获得高光催化降解效率，历经8次循环使用后，CX-TiO2-La(0.5)仍对增溶PHE有较高的移除率。

Abstract:

In this study, CX-TiO2-La(x) series composites were prepared by sol-gel method and doped with metal element lanthanum to modify TiO2, which were used to treat simulated soil leaching (solubilization) wastewater under visible light, and the structure and properties of the materials were characterized. The results show that CX-TiO2-La(x) series composites can achieve enrichment and degradation of solubilized PHE. All CX-TiO2-La(x) series composites is mainly composed of amorphous carbon, rutile TiO2 and La2Ti2O7. When the addition of lanthanum chloride was 0.5%, the removal efficiency of CX-TiO2-La(0.5) for solubilized PHE was the best, reaching 83.6% (irradiated with 500 W xenon lamp for 5 h). CX-TiO2-La(x) series composites were all with characteristics of mesoporous, moreover, the composite second-order kinetic model of PHE adsorption process fits well with Langmuir model with a spontaneous chemical adsorption process. It was speculated that the heterojunction structure formed to expanded the corresponding photocatalytic range of TiO2, and achieved high photocatalytic degradation efficiency under visible light. After 8 cycles, CX-TiO2-La(0.5) still had a high removal efficiency of solubilized PHE.