磁场驱动下g-C3N4量子点/单层Bi2WO6异质结对景观水体硝态氮和氨氮光促协同转化机理研究

Excessive nitrate-nitrogen and ammonia-nitrogen in water has become a common and serious problem in the world. Photocatalysis is considered to be the most promising denitrification technology for water bodies, but the effect of photocatalytic denitrification is limited by photocatalytic activity, secondary pollutants (such as nitrite and nitrogen oxides, etc.), and dependence on sacrificial agents, etc. This project intends to improve the photocatalytic denitrification effect and the selective conversion efficiency of nitrogen through the internal optimization of photocatalytic materials, the external strengthening of the magnetic field, and the synergistic removal of nitrate-nitrogen and ammonia-nitrogen. Characterization technology, physical chemical detection technology and density functional theory simulation calculation will be applied to explore the controllable preparation rules for the optimization of g-C3N4 quantum dots/monolayered Bi2WO6 heterojunction photocatalytic materials, to confirm the intrinsic enhancement mechanism of photocatalytic decomposition efficiency of nitrate-nitrogen and ammonia-nitrogen driven by the magnetic field, and to clarify the microscopic mechanism of synergistic transformation and molecular evolution of nitrate-nitrogen and ammonia-nitrogen. It is of great significance to profoundly reveal the rules of selective transformation of nitrate-nitrogen and ammonia-nitrogen in water, and it will provide theoretical basis and technical reference for the development of photocatalytic technology for effective denitrification and decontamination of water bodies.

水体硝态氮和氨氮超标已成为全世界普遍存在的严重问题。光催化被认为是具有广阔应用前景的水体脱氮技术，但脱氮光催化剂的活性需要提高、反应副产物（亚硝酸盐、氮氧化物等）对环境存在二次污染等因素限制其进一步发展。本项目通过将g-C3N4量子点引入单层Bi2WO6纳米片结构中形成异质结实现材料的内部优化、利用并调控磁场对光催化反应进行外部加强、以及提出构建硝态氮和氨氮的协同互促体系，综合提高光催化脱氮效果及对氮气的选择性转化效率；利用表征技术和物理化学检测技术，结合密度泛函理论模拟计算，探究g-C3N4量子点/单层Bi2WO6异质结光催化材料优化的可控制备规律，分析磁场对提高硝态氮和氨氮光催化分解效率的内在增强机制，阐明硝态氮和氨氮协同互促及分子演变的微观机理。该项目研究对深刻揭示水体中硝态氮和氨氮光促选择性转化规律有重要意义，为发展光催化技术有效应用于水体脱氮净化提供理论依据和技术借鉴。

氮污染是全球水体中普遍存在的严重问题。光催化技术在水体脱氮处理中具有广阔的应用前景。本项目主要通过调控制备方法、反应条件等将氮化碳量子点与单层钨酸铋纳米片的耦合形成异质结，实现复合材料的可见光响应及强光催化活性，并利用外部磁场调控光催化脱氮的反应过程，以及构建硝态氮和氨氮的协同互促脱氮体系，从而实现水体氮污染的有效治理。项目中采用了X射线衍射、X射线光电子能谱、紫外可见光吸收光谱、电化学阻抗等现代检测技术，从材料的结合方式、磁场的影响规律和污染物的转化途径等方面综合揭示磁场对g-CNQDs/BWO光催化去除硝态氮和氨氮的增强机制，以及硝态氮和氨氮光催化反应协同互促的内在机理。本项目的研究表明磁场增强的g-CNQDs/BWO复合材料光催化体系在同步去除实际水环境中的硝态氮和氨氮方面具有巨大的潜力。