【摘要】 近年来,随着核能在我国的崛起和发展,开发简单、高效、应用性强的吸附材料用于锕系阳离子的吸附分离变得愈加迫切.金属有机框架材料(metal-organic frameworks, MOFs)由于其合成简单、结构可控、功能易调、孔隙率高、比表面积大等特点被认为在锕系阳离子吸附分离领域具有广阔的应用前景.本文从材料设计角度出发,综述了MOFs用于锕系阳离子吸附分离的最新研究进展,着重讨论了表面修饰、缺陷、功能复合、金属节点等对MOFs吸附性能的影响,以厘清MOFs材料在锕系阳离子吸附应用中的构效关系.最后,提出了目前MOFs用于锕系阳离子吸附分离存在的问题,并对未来的相关研究方向进行了展望.更多还原

【Abstract】 With the rise and development of nuclear energy in China in recent years, how to dispose spent fuel has become an urgent problem, so it has become increasingly urgent to develop simple, efficient and applicable sorption materials for actinide cation separation. Metal-organic frameworks(MOFs) are considered to have broad application prospects in the field of actinide cation separation due to their unique properties such as easy synthesis, controllable structure, easy function adjustment, high porosity and large specific surface area. Due to the limitation of the structure of the original metal organic framework materials, the selectivity, stability and adsorption properties are limited. In recent years, researchers have improved the activity and stability of the original MOFs by different modifications, so that they are more suitable for adsorption and separation of actinide cations. In this paper, the latest research progress of MOFs for actinide cation separation is reviewed from the point of view of material design. We divide the material modification method into four parts:(1) Surface modification. Functional MOF materials were constructed by introducing functional groups, such as amino group, carboxyl group, phosphonate group and amidoxime group, in order to improve the dispersion of MOF materials in water system based on the hydrophilic/hydrophobic properties of the functional groups themselves. Moreover,the chelation of functional groups to uranyl ions provides more active coordination sites for MOF skeleton and further improves the adsorption performance of MOF.(2) Defect treatment. The use of defect engineering not only improves the adsorption performance of MOFs but also maintains the original stability of the material. By introducing different regulators in the synthesis process, ligand defects are constructed in the MOFs, and the absence of linkers exposes the Zr-O active site to adsorb uranyl ions. In addition, by adjusting the amount of regulator added, the MOF materials with different defective amounts can be obtained.(3) Functional composite. Compounding MOFs with other materials, on the one hand,improves the characteristics of powder materials that are not easy to be processed later; on the other hand, combines with the advantages of the two materials to obtain more outstanding physical and chemical properties and broader application prospects.(4) Metal nodes. Based on the designability of MOF materials, the same ligand was selected to prepare MOF materials with the same topological structure by replacing different metal nodes. Because of the difference in the radius of metal ions, different MOF nodes have different adsorption mechanisms for actinide cations, resulting in differences in adsorption properties. Overall, the key factors affecting the adsorption capacity of MOFs were explored through detailed analysis of the topological structure, adsorption performance and adsorption mechanism of the materials. At the end of this paper, the existing problems in the application of MOFs in the separation of actinide cations were proposed. Specially, three aspects were included. Firstly, due to the structural properties of MOF materials themselves, they cannot maintain the stability of the material in some specific environment; Secondly, there are many competing ions in the real system, and the MOF materials reported so far are not able to realize the specific recognition of actinide cations. Finally, at present, the adsorption mechanism of actinide cations by MOF is mostly determined by some auxiliary means. More direct and advanced methods are needed to characterize the “real” adsorption mechanism.更多还原