异原子共价掺杂石墨相氮化碳催化臭氧的界面作用机制研究

The hazardous micropollutants, have been ubiquitously detected with very low concentration in water systems. Most of these compounds could be persistent in the environment for a long time and easy to accumulate in the organisms, which could pose a potential threat to aquatic ecosystem and human health. The proposed study, taking two typical hazardous micropollutants in the reclaimed water as the target pollutants, based on the optimization of catalyst structure, through the heteroatom covalent bond-doping modification of g-C3N4 and the structure performance analysis, aims to establish covalent bond-doping g-C3N4/O3 catalytic system, explore the degradation performance of the hazardous micropollutants, and further to explicit the key processes for the removal and transformation of the hazardous micropollutants. Thereafter, based on a variety of in-situ characterization and the isotope tracer methods, this study will clarify the transformation behavior of O3 on the different catalyst surfaces and the degradation of micropollutants in the catalyst interface, then to reveal the difference on the surface reactive sites and the interfacial mechanisms of heteroatom covalent bond-doping g-C3N4 in heterogeneous catalytic ozonation. Finally, the structure−activity relationships between the electronic characteristics of the different catalysts and the catalytic performance of heteroatom covalent bond-doping g-C3N4 will be elaborated by the density functional theory calculation. This project would provide theoretical basis for selection, synthesis and application of high efficiency and stable catalytic materials in catalytic ozonation system. It would also provide with the important basis of the theory and references of the technology with the results obtained in the study for searching for the novel approach of economic, high performance and environmental benefits to the removal of the hazardous micropollutants in wastewater treatment.

水系统中有害微量污染物多具有较强的环境持久性、生物活性及生物累积性，对生态系统和人类健康构成了潜在风险。本项目以回用水中典型有害微量污染物为研究目标物，以催化剂构型优化为出发点，通过石墨相氮化碳（g-C3N4）本征结构中金属和非金属共价掺杂及结构性能的表征，探讨异原子共价掺杂g-C3N4/O3多相催化体系对有害微量污染物的降解性能及影响因素，明确有害微量污染物的去除途径及关键转化过程；通过多种原位表征和同位素示踪手段考察O3在不同催化剂表面的转化行为及污染物在催化剂界面的降解过程，揭示异原子共价掺杂g-C3N4的表面反应活性位点及界面作用机制，借助密度泛函理论模拟计算深入明晰异原子共价掺杂g-C3N4的电子结构与催化性能之间的构−效关系。本项目为新型高效稳定臭氧催化剂的筛选和制备提供理论基础，亦为多相催化臭氧技术应用于水处理中实现有害微量污染物的去除提供技术支持。

目前，经济、高效、化学性能稳定及环境友好型的臭氧催化剂是臭氧催化氧化技术研究及应用的关键。针对传统催化剂稳定性差及界面作用机制不明等问题，在该项目的资助下，系统性地开展了新型异原子共掺杂g-C3N4复合材料的制备及表征、催化臭氧降解污染物的性能及其界面作用机制的研究。首先通过两步煅烧法及一步水热合成法制备了零价锌负载g-C3N4和氧修饰g-C3N4复合材料，两种材料具有优异的催化臭氧活性，能够实现水中阿特拉津的快速降解及矿化，具有宽泛pH值适用性及循环稳定性。多种表征结果揭示，异原子掺杂能够改变g-C3N4的晶体结构和电子分布，增强电子转移过程，形成部分结构缺陷及更多的活性位点，显著促进体系中活性氧物种的转化与生成，从而实现污染物的快速降解和矿化。异原子掺杂g-C3N4为高效稳定臭氧化催化剂应用与经济和环境友好的废水处理提供了可行性，在饮用水、回用水以及工业废水处理中具有广阔的应用前景。

内容获取失败，请点击重试