磁性纳米材料Fe3O4@BiOX(X=Br,Cl,I)的制备及光催化抗生素污染物的机理研究

The antibiotics residues in the environmental samples has become a serious problem in recent years, which threatens both the ecosystem security and human health. In this project, magnetic Fe3O4@BiOX (X=Br,Cl,I) core-shell nanomaterials with Fe3O4 as source cores will be prepared, and their photocatalytic performance on the degradation of four representative antibiotics in aqueous solution under visible light irradiation will be investigated. The magnetic, structural and surface properties of the prepared samples are controlled by varying synthesis conditions, so as to obtain the catalyst with best photocatalytic activities. To explore the catalytic mechanism, the changes of the surface properties and the surface active sites of the magnetic samples are measured during the experimental process, and the reaction intermediates and reactive species will also be identified. Based on the mechanism and intermediates analysis, the possible degradation paths of the model antibiotics will be proposed. Meanwhile, in the view of practical application, the recover and regeneration of the prepared Fe3O4@BiOX (X=Br,Cl,I) nanomaterials will be studied, and extended experiments are conducted to explore the antibacterial activity of the target pollutants. The obtained nanomaterials will be also adopted to degrade antibiotics in real water samples. This study aims at synthesizing highly efficient visible-light-responsive magnetic nanomaterials, which can be potentially applied in wastewater treatment processes.

近几年环境中残留抗生素的污染问题日益突出，已经对生态系统安全和人体健康构成了严重威胁。本项目拟采用多相催化技术，制备以纳米Fe3O4为核，纳米卤化氧铋为壳的磁性核壳催化材料Fe3O4@BiOX(X=Cl,Br,I)，在可见光下催化降解水中的抗生素类有机污染物。通过改变制备条件控制催化剂的磁性、结构和表面性质；表征光催化降解抗生素过程中，催化剂在不同反应阶段表面性质和表面活性位的变化，识别降解产物和活性物种，揭示催化剂性质和催化性能的关系，阐明催化降解抗生素的机理；研究催化剂的回收和再生、抗生素降解动力学和降解路径，考察降解产物的抑菌活性。在此基础上，将制备的催化剂应用于实际环境水体中抗生素的去除，研究其催化处理效果。本项目可望获得基于可见光激发的高效易回收的复合磁性纳米材料，用于处理污水中的抗生素，具有一定的理论价值和实际意义。

本项目针对水环境中抗生素和偶氮染料等有机物的纳米去除技术开展基础性研究，采用简单便捷的沉淀法，水热法等化学技术，制备卤化氧铋，钼酸铋和磷酸铋等铋系纳米催化材料，在可见光下催化降解抗生素和偶氮类染料等有机污染物。针对常用光催化材料存在形貌不易控、制备程序复杂、回收循环使用效率低，制约该技术在环境工程领域实际应用这几个主要问题，利用晶种生长技术构建Fe3O4@BiOX(Br,Cl,I)、Fe2O3@BiOBr和Fe3O4@C@Ag复合磁性纳米材料，该催化剂在水中具有良好的分散性、磁性回收效果和高催化活性。在可见光照射下，可以高效降解抗生素和偶氮杂环类有机污染物，识别了降解产物和活性物种，揭示催化剂性质和催化性能的关系，阐明催化降解抗生素等有机物的机理，发现合成的磁性催化剂在数次循环试验后，仍然保持很好的催化活性。