新型阳离子型铀酰-有机杂化材料的设计制备及其离子交换应用研究

Ionic exchange method based on cationic actinide-organic hybrid materials is a new strategy to achieve the separation of anions (such as TcO4-) in spent nuclear fuels. As a representative type of actinide hybrid material, uranyl-organic hybrid materials have not been used to the separation of anions through ionic exchange. This proposal aims to design and synthesize novel cationic uanyl-organic hybrid materials for the separation of anions by ionic exchange. To acquire a new type of cationic uranyl-organic coordination polymer, a series of specially designed organic ligands involving pyridinium groups will be synthesized and used as reaction precursors to prepare the corresponding uranyl compounds, among which several uranyl compounds with cationic uranyl-organic backbones will be selected. And then, the targeting uranyl-organic hybrid materials with good self-stability, water stability and acid stability will be obtained through combination with structural modification of organic ligands via halogenation (-Cl, -Br, -I) and supramolecular encapsulation of macrocyclic hosts (such as cucurbiturils). On the basis of these newly-prepared hybrid materials, we will focus on the ionic exchange and separation behaviors of them for certain anions (ClO4-, CrO4-, Cr2O72-, SO42- and TcO4-). Meanwhile, we will explore the effects of materials, exchange conditions and other factors on the exchange capacity and selectivity. Finally, radiation stability of those materials exhibiting good exchange performance with TcO4- will be studied so as to evaluate the potentials applying them to the real system with high irradiation. It is expected that this project will enrich the library of actinide functional materials, and provide the initial basis for the application of uranyl-related materials in anion ionic exchange and separation.

基于阳离子型锕系杂化材料的离子交换法是实现乏燃料中TcO4-等阴离子分离的一种新思路。作为最典型的锕系杂化材料，铀酰-有机杂化材料在阴离子交换方面的应用还未见报道。本项目拟开展新型阳离子型铀酰-有机杂化材料的设计制备及其阴离子交换应用研究。首先通过设计合成的含吡啶嗡盐结构的有机羧酸配体制备新型阳离子型铀酰-有机杂化材料，并结合卤代修饰或大环包合的方法对其进行结构调控，筛选出稳定性好、性质优良的材料。在此基础上，评价所制备的铀酰-杂化材料通过离子交换分离TcO4-等典型阴离子的性能，重点考察材料种类、离子交换条件等因素对其交换容量和选择性的影响。最后，对可以与TcO4-进行高效离子交换的杂化材料进行γ辐照稳定性研究，评估其在强辐照条件下应用的可行性。本项目的完成将可以丰富铀酰功能材料种类，并为铀酰相关材料在阴离子交换分离方面的应用奠定基础。

基于阳离子型材料的离子交换法可以实现乏燃料中高锝酸根等阴离子高效分离，是放射性阴离子分离的重要手段，而采用锕系杂化材料如铀酰-有机杂化材料代表了一种全新的尝试。本项目的主要研究内容是开展新型阳离子型铀酰-有机杂化材料的设计制备及其阴离子交换性能评价，希望为铀基杂化材料在阴离子交换分离方面的应用奠定研究基础。通过本项目研究，我们设计合成了十余种新型铀酰-有机杂化材料，初步建立铀酰-有机杂化材料的结构规律，并结合多种结构修饰策略筛选出两类结构稳定、理化性质优良的铀酰-有机杂化材料；围绕优化筛选的材料，系统评估了阴离子去除性能，详细解析了相应的去除机理，并考察了影响材料分离性能的多种影响因素。从本项目的研究结果来看，通过超分子包合或提高分子骨架的共轭性可以显著提高材料的结构稳定性，而采用目标阴离子具有适应性识别能力的阳离子型材料可以实现高锝酸根高选择性的分离。本项目也取得了较好的学术成绩，所产生的有关研究成果已整理发表多篇SCI论文，包括Nature Communications, Chem. Eur. J., Inorg. Chem., Cryst. Growth & Des., Dalton Trans.等国际知名刊物，相关成果也得到了国际、国内同行的关注和好评，并多次引用。本项目所取得的相关成果作为重要成果之一入选国家自然科学基金委员会简报2020年第6期（总505期）“我国乏燃料后处理技术基础研究取得重要突破”，对放射性阴离子核素分离策略的制定具有重要参考价值。