双金属MOFs电纺纤维膜构筑及其活化过硫酸盐氧化磺胺类抗生素的机理

Persulfate (PS) chemical oxidation processes using sulfate radicals (SO4-·) as oxidants to degrade environmental emerging contaminants such as sulfonamides has become a research focus in recent years. Based on low accessibility of Fe2+ Coordinatively Unsaturated Sites (CUS) and the ligand dissociation and skeleton collapse caused by CUS electron transfer, current iron-based Metal-Organic Frameworks (MOFs) possess low catalytic capacity, low stability, and short operation life. On this basis, novel, easy-separated and recovered bimetal-organic frameworks and its electrospun fibrous with 3d-4f configuration and Fe2+CUS will be constructed using electrospinning technology. The influence of Ln metallic ions, the bonding modes between MOFs and fibers, as well as other regulatory factors on CUS accessibility, coordination mode, crystal defects, topology and catalytic performance of the catalysts will be elucidated. The controlling factors and its regulatory mechanism which restrict the structure and properties of the catalysts will be clarified. The evolving mechanism of CUS and the degradation mechanism of SAs by free radicals will be revealed. The research results will provide the design guidance of highly efficiency MOFs-based catalysts, the theoretical guidance and technical support for controlling the generation and release of sulfate radical in MOFs activated PS systems, as well as realizing the effective degradation of SAs and other non-degradation contaminants.

过硫酸盐（PS）化学氧化法采用硫酸根自由基（SO4-·）氧化降解污染物，近年来成为处理环境新兴污染物磺胺类抗生素（SAs）的研究热点。针对现有铁基金属有机骨架（MOFs）活化PS因Fe2+配位不饱和中心（CUS）可及度低、CUS电子传递过程致配位解离导致催化活性差、骨架稳定性低、重复使用效率受限的问题，本项目拟结合静电纺丝技术设计构筑易于分离回收的3d-4f型Fe2+CUS双金属MOFs及其电纺纤维膜，阐明Ln离子、MOFs与纤维成键模式等调控因素对催化剂CUS可及度、配位模式、晶格缺陷、拓扑结构和催化性能的影响，明确制约催化剂构效性能的控制因子及其调控机制，以及揭示活化反应过程CUS衍变机制及自由基氧化SAs的反应机理。研究成果将为合成高效催化PS的MOFs催化剂提供设计指导，同时为采用MOFs调控SO4-·释放、实现水中SAs的有效降解提供理论依据和技术支持。

以金属有机骨架（MOFs）为催化剂的过硫酸盐活化体系面临MOFs构效性能低、粉体MOFs纳米微晶难分离的问题，导致催化剂活性位点的可及度受限。增强氧活性物种（ROS的产生），提高催化寿命和催化效率是推动该技术在水污染控制领域应用的重要方向之一。研究以设计构筑能高效活化过硫酸盐且性能稳定的MOFs膜为目标，结合原位结晶与静电纺丝技术合成出易于分离回收的锌基MOF复合纤维膜Zn-ZIF-65/PAN，提出利用层层自组装法对膜材料进行再生。研究确定了体系涉及的ROS物种，阐明了ROS氧化污染物的反应机理。在此基础上通过调控MOF预沉积生长因子，调变原位结晶过程晶体生长方式，制备出3d-3d型Zn-Co-ZIF/PAN双金属膜材料，ZIF微晶与PAN成键模式得到优化，催化活性位点的多样性和可及度提高，体系的氧化效能和膜材料的使用寿命得到提升与改善。研究结果可为高活化过硫酸盐性能的MOFs膜材料催化剂的合成提供理论指导，同时为基于MOFs的高级氧化体系处理水环境污染物提供技术支持。