新型共价有机骨架材料吸附分离锕系离子的理论和实验研究

With the development of nuclear power, safe disposal of spent nuclear fuel especially high level liquid waste is essential for the sustainable development of nuclear energy. Highly efficient material for actinide separation is an important field of spent nuclear fuel reprocessing. Covalent organic frameworks (COFs) possessing the advantages of low density, large surface area, tunable pore size and structure, facilely-tailored functionality, have gained extensive attention all over the world. This project aims to design and synthesize highly efficient COF materials for adsorption of actinides by using multiscale theoretical methods and experimental techniques. To explore highly efficient ligands for separating actinides, the organic monomers and groups of COFs will be optimized firstly. And then, novel COF materials will be synthesized experimentally. Combining computational chemistry and experimental techniques, we will mainly focus on the adsorption and separation behavior of these materials for actinides, the factors affecting adsorption properties including the functional groups, pore size, synthesis methods and adsorption conditions, and the adsorption mechanism of the COF materials. Meanwhile, to evaluate the radiation stability of the COF materials, the structures of the pores and the functional groups will be also studied before and after irradiation. It is expected that this project will provide valuable clues for establishing the initial basis for COF materials application in high level liquid waste.

随着核电的发展，乏燃料的后处理尤其是高放废液的安全处理与处置已成为制约核能可持续发展的关键。新型高效锕系元素分离材料是目前乏燃料后处理的前沿和热点研究课题之一。由于共价有机骨架材料（COFs）具有密度低、表面积大、稳定性高、易于结构调整和修饰等优点，近年来备受关注。本项目拟采用多尺度模拟方法和实验手段设计和制备对锕系离子具有高效选择性吸附能力的COFs材料。首先对COFs材料的有机单体和侧臂基团进行优化设计，筛选对锕系离子具有高效络合能力的基团。在此基础上，制备新型COFs材料，并通过理论和实验结合的方法研究其对锕系离子的吸附和分离行为，考察COFs材料的功能基团种类、孔径尺寸、合成方法和吸附条件对吸附行为的影响，探讨吸附分离机理。同时，研究辐照前后COFs材料的孔道和功能基团结构的变化，建立评价COFs材料辐射稳定性的方法。本项目的完成将为COFs材料在高放废液处理方面的应用奠定基础。

目前高放废液的安全处理与处置是制约核能可持续发展的关键。本项目采用理论和实验结合的方法设计和制备对锕系离子具有高效选择性吸附能力的COFs材料。理论研究发现磷酸类COFs材料的有机单体和配位基团对锕系离子具有较强的相互作用，在此基础上，制备了磷酸基功能化的COFs材料，并研究其对锕系离子的吸附和分离行为，考察吸附条件对吸附行为的影响，重点研究材料的吸附热力学、动力学、离子选择性、辐照稳定性、循环利用等方面的性质，同时通过实验和理论研究探讨吸附分离机理。此类COFs材料在高酸度条件下表现出优良的吸附行为，并且具有吸附容量大、选择性高、循环利用好等优点。