基于铀识别的多孔配位聚合物及其复合膜的制备和吸附机理研究

As a new generation of porous materials, the coordination polymers (MOFs) have enormous potential applications. The structures of MOFs can be regulated and its surface can be easily modified. So we can prepare a new-style functional uranium adsorption materials by taking advantage of the characterizations of MOFs. The MOFs' excellent recognition of uranium ions is the key supporting technique in this field. We propose a new concept, namely, synergistic recognition, the cooperation of the size of cavity, the open active groups of functional ligands and the host-guest hydrogen bond as the recognition sites, will achieve a high selectivity of the hydrated uranium ions. Based on the above synergistic recognition concept, this study intends to synthesize a series of functional organic ligands with different substitutes and then to construct various MOFs through self-assembly of metal ions and these organic ligands. The size regulation of pores and the open functional coordination groups being introduced on the surface of pores also serve as excellent recognition sites and cooperate together to improve the adsorption selectivity and the amount of adsorption of uranium ions. The project will explore the different recognition capacities of different pore-size or substituents in order to screen out the appropriate structures, and investigate the recognition mechanism. Further, the efficient composite membrane will be prepared to combine the MOF candidates with some metal meshes or polymer resins. Moreover, its performance of uranium ions adsorption and its mechanism of action also will be investigated. This project will put forward an scientific argument based on the surface synergistic recognition effects between the guest uranium ions and host porous frameworks, which will enrich the new research areas of the porous coordination polymers and open a new approach of uranium separation.

新兴的多孔配位聚合物（MOF）蕴藏着巨大的潜在应用价值。利用MOF结构可调控、表面易修饰的特点，可制备新型铀吸附功能材料。其铀的特异性识别将是该领域应用的核心支撑技术。我们提出协同识别新概念，即对于水合铀离子，MOF的空腔尺寸、配体功能基团和主客体间氢键等各识别位点的协同贡献，实现识别的高选择性。拟合成具有不同取代基的配体,以之与金属簇自组装构筑MOF。调控孔径大小，并在孔道表面引入能与铀离子形成配位作用的开放官能团，作为铀离子的特异识别位点，以提高铀吸附选择性。系统探索不同的孔道尺寸/取代基对铀离子识别能力，研究其识别机理。在此基础上，进一步将之与金属网或者高分子树脂结合起来,制备高效铀吸附的新型MOF复合膜材料，考察其铀吸附性能并研究其作用机制。本研究将为多孔体系主客体间的表面效应对铀离子的特异识别，得出可行性的科学论据。丰富多孔配位聚合物新的研究领域，开辟铀识别分离的新思路和新方法。

功能化多孔金属有机框架化合物（MOF）因其有趣的拓扑结构、可调节的孔道的特性、优异的性能以及潜在应用前景，而备受关注。本项目从金属有机框架化合物结构可调控、表面易修饰的特点出发，通过合理选择功能化的多羧酸配体与过渡金属离子构筑了新颖结构的金属有机框架化合物，研究其相关性质，以之作为新型铀酰离子吸附材料。设计合成一系列羰基功能团的多羧酸配体。并通过溶液法、传统的溶剂热合成法以及微波辅助合成技术，制备了13个过渡金属功能配合物，通过单晶衍射表征了化合物的结构，研究了部分化合物的荧光和磁性能。努力探讨材料的结构与性能的构效关系: 探讨了不同共轭体系的共配体实现了配位聚合物的光致变色性能调控；通过刚性小分子共配体的引入，在一定程度上实现了线形三核金属羧酸功能配合物的结构调控:从无孔结构层状配位聚合物到刚性共配体柱撑的二维微孔结构。研究了不同功能基团表面修饰金属有机框架化合物孔道，对其铀吸附行为的影响: 相对于巯基而言，羰基功能的金属有机框架化合物，表现出了更加优异的铀吸附性能。表明在孔道表面引入合适的并能与铀离子形成配位作用的表面功能基团，作为铀离子的特异识别位点，可以提高其铀吸附性能。同时摸索了金属有机框架化合物/高分子膜复合材料的制备条件。相关研究成果为功能化金属有机框架材料和复合膜材料制备，及其在铀吸附的应用领域具有良好的前景和重要的科学意义。