新型功能化金属-有机骨架材料的配体设计与可控制备及其对Co-60的分离行为与机理研究

As a very useful radioactive nuclide in industry, agriculture, medicine, science and other areas, Co-60 attracts growing concern in recent time, due to its long half-life and strong γ emission. Obviously, separation and enrichment of Co-60 from radioactive wastewater is beneficial to both recycle resource and eliminating the harm of radioactive waste on the ecological environment. However, the existing separation materials still suffered from low adsorption capacity, poor selectivity and stability, which are difficult to meet the efficient separation and enrichment requirements of Co-60 from aqueous solutions. Due to the superiority of metal-organic framework (MOFs) materials, such as strong functionality, high porosity, large specific surface area and adjustable pore size, this project aims to realize the controllable preparation of MOFs materials by molecular design of organic ligands and theoretical calculation for chelating ability of ligands with cobalt and the physical and chemical properties of potential materials. In addition, the adsorption behavior and mechanism of Co(II) on MOFs would be exhaustively investigated to realize the efficient and selective separation of Co-60 from aqueous solutions. The main research contents will include: 1) design of ligands and their coordination ability for cobalt; 2) controllable preparation of the novel MOFs; 3) adsorption behavior of Co(II) on the resulted MOFs materials; 4) adsorption mechanism of Co(II) on the MOFs materials. The purposes of this study are to build a new procedure based on theoretical calculation and experiments, which can lead to the controllable preparation of MOFs materials, obtained some functional MOFs materials with stable performance for radiation resistance and good separation performance for Co(II), and clearly understand the adsorption behavior and mechanism of cobalt on these novel MOFs. This project would not only provide new idea and method for the separation of Co-60 from radioactive wastewater, but also accumulate important experience for separation of other heavy metal ions in wastewater.

从放射性废水中分离Co-60既有利于资源回收，也可减少废物对生态环境的影响。但现有分离材料仍然存在吸附容量偏低、选择性差、稳定性不强等不足，难以满足对Co-60的高效分离要求。本项目拟通过有机配体的分子设计与螯合能力和材料理化性质计算，实现新型金属-有机骨架（MOFs）材料的可控制备，并探讨其对Co的吸附行为与机理，以实现溶液中Co-60的高效选择性分离。主要内容有：1）MOFs配体设计及与钴离子的螯合能力研究；2）功能化MOFs材料的制备；3）MOFs材料对溶液中Co的吸附行为研究；4）MOFs材料对Co的吸附机理研究。通过本课题，建立基于理论计算与实验相结合的MOFs制备新方法，获得耐辐照性能稳定、对Co分离性能优良的功能化MOFs新材料，了解其对Co的吸附行为与规律，揭示其吸附机理。该项目的执行不仅有望为含Co-60放射性废水的处理提供新思路，对其它重金属废水的处理研究也有借鉴意义。

从放射性废水中分离Co-60既有利于资源回收，也可减少放射性废物对生态环境的影响。但现有分离材料仍然存在吸附容量偏低、选择性差、稳定性不强等不足，难以满足对Co-60的高效分离要求。为此，本项目以MOFs材料为基体，通过理论计算与实验相结合的方式开展了新型功能化MOFs材料的配体设计与可控制备及其对Co(II)的分离行为和机理研究，取得了以下研究进展：1）建立了通过理论计算引导配体设计实现功能化MOFs材料可控制备的新方法；设计并制备了不同配体功能化的MOFs材料，发现功能化MOFs材料对Co(II)的分离能力受接枝配体种类、链长、MOFs基体种类等多种因素影响；制备的功能化MOFs材料在辐照强度20-80 kGy下是稳定的，有望用于真实放射性废水中Co-60的分离。2）通过将葡萄糖、磺酸基和吡啶等环境友好的小分子或功能基团引入磁性MOFs材料提高了MOFs材料对Co(II)的分离能力，特别是通过外加磁场快速实现溶液与吸附材料的分离对于操作人员远离放射环境，实现Co-60安全分离具有重要现实意义。3）开展了MOFs离子印迹聚合物的制备及对Co(II)的选择性分离研究，发现以2-吡啶甲醛和乙烯基吡啶为单体，锆基MOFs材料为基体，通过离子印迹技术制备MOFs基离子印迹聚合物能够实现Co(II)的高容量、高选择性分离。4）开展了MOFs膜对Co(II)的分离行为与机理研究，发现通过静电纺丝预先构筑孔隙率高、均一性好的MOFs纳米纤维膜，再通过合成后修饰技术将膜表面接枝对Co(II)具有配位能力的有机小分子，能从技术上解决单纯依靠MOFs孔道分离Co(II)时分离效率不高的问题，获得的材料具有较好的辐照稳定性，为进一步将MOFs材料用于工程实际中Co-60的分离提供了新思路。这些研究结果不仅对Co-60的高效、高容量、高选择性分离具有重要的指导意义，对溶液中其它放射性核素和重金属离子的分离去除也具有参考和借鉴价值。.到目前为止，基于本项目，已在国内外发表和交流论文16篇，其中正式发表SCI收录论文13篇，国内EI期刊论文1篇；多人次参加全国学术交流会，先后有3名博士生、3名硕士生参与本课题的研究；上述研究结果已和中国核动力研究设计院反应堆运行研究所相关人员进行多次交流，拟将本项目研制获得的新型功能化MOFs材料用于含Co-60放射性实际废水的处理实验研究。