铋基异质结高效界面构建及其同步去除水中重金属和芳香类有机物的机理研究

The long-accumulated and exposure of heavy metal ions and aromatic organic pollutants in aquatic environments has aggravated the risk of water quality deterioration greatly and threatened the human health seriously. Thus, the research on advanced treatment of heavy metals and aromatic organic pollutants has a vital significance. The high efficient bismuth based heterojunction composite photocatalysts will be synthesized by soft chemical method and the photocatalytic degradation mechanism of heavy metals and aromatic organic pollutants in water will be discussed. The bonding interface configuration of different bismuth-based oxide components will be regulated. The mechanism for enhanced photocatalytic performance by the micro-interface structure of heterojunction will be studied. We will also study the effect of aromatic organic compound on the photocatalytic reduction of heavy metal ions from molecular structure perspectives. Based on the.pollutant intermediates by photocatalytic degradation, the mutual degradation pathways of heavy metals and aromatic organic compounds in water and the photocatalytic degradation mechanism will be studied. The results of this work are expected to provide a theoretical basis for the efficient photocatalytic degradation of composite pollutants in water.

水环境中无机重金属和芳香类有机污染物的长期暴露和累积加剧了水质恶化风险，严重威胁人类健康，因此研究安全高效的重金属和有机芳香类复合污染物的处理方法具有重要意义。本项目将采用软化学法合成高活性的铋基异质结光催化剂，开展其对水中重金属与芳香类复合污染物的同步光催化降解机理研究。项目通过调控不同铋基复合氧化物组分间的结合界面构型，探讨异质结微界面结构增强光催化剂性能的作用机制，并从分子结构层面来研究不同芳香类有机物对光催化还原重金属离子的影响，以复合污染物光催化降解过程的中间产物为基础，揭示水中重金属与芳香类有机物的交互降解途径，阐明其光催化降解机理，为可见光下高效光催化处理水中复合污染物的可行性提供理论依据。

本项目通过对钛酸铋半导体的二维片状、多面体微结构等形貌可控制备，以熔盐法原位合成了Bi4Ti3O12/Bi2Ti2O7钛酸铋异相结，超声辅助法构造了Bi4Ti3O12/g-C3N4 2D微纳米片复合光催化剂，水热法合成了Bi12TiO20/RGO多面体微结构复合光催化剂，通过不同的界面微结构调控及能带结构调控，实现了光生电子-空穴对的有效分离，并初步研究了铋基异质结光催化剂对水中单一重金属离子或有机污染物的降解，以及重金属离子和有机污染物混合污染物的协同降解机制，研究了反应过程中有机酸、无机酸根离子、无机盐离子共存条件下对光催化反应的影响，催化反应过程中活性基团及反应过程有机物分子的结构变化等，为可见光下铋基异质结构催化剂对水中复合污染物的降解机制有了初步认识。此外，还通过热缩聚法和液相超声剥离法制备了纳米片状氯掺杂石墨相氮化碳g-C3N4、非金属元素(硫、氯、磷)掺杂g-C3N4，及其对重金属离子及有机污染物的光催化降解效率、降解动力学及反应过程中的参与反应的活性氧化自由基等研究。该项目的实施为新型光催化剂的性能增强及其对复合污染物光催化降解过程与机制的探索提供了重要的基础数据和信息支持。