共价有机框架材料的构筑及其在高放废液锕系离子吸附中的应用研究

Safe treatment and disposal of radioactive actinide waste generated by nuclear power plays a critical role in the nuclear industry. Partition and transmutation is believed as one of effective solutions to this problem. Treatment and disposal of highly radioactive waste is the key issue to nuclear reprocessing. Considering the strong acidic environment of high level radioactive waste, to resolve the protonation and instability of adsorbing materials, it is highly desired to develop novel functionalized materials for separation of actinide ions at highly acidic radioactive waste. On the basis of quantum chemical calculations and experiments, this project intends to design and synthesis of novel COFs for separation of actinide ions. Then, the adsorption performance of COFs towards actinide ions will also be investigated to establish the structure-activity relationship between COFs and adsorption properties, and propose program to separate actinide ions from highly acidic radioactive waste. Additionally, the interaction mechanism of COFs with actinide ions will be investigated by traditional spectra, synchrotron radiation-based technique and so on. We expect that this proposal can develop more efficient materials to separate all the actinide ions simultaneously from highly acidic radioactive waste, provide new materials and strategies for treatment and disposal of high acidic radioactive waste.

作为核能发电产生的锕系放射性废物，其安全处理处置是核电工业的重要组成部分，是核燃料循环技术关键环节之一，分离-嬗变被认为是解决这一难题的有效途径。高放废液的处理处置是乏燃料后处理的重要环节。考虑到高放废液的强酸性环境，为解决高酸度条件下功能材料质子化和不稳定的难题，非常有必要设计和制备新型的锕系吸附功能材料。本项目拟通过量子化学理论计算和实验相结合，设计并合成一系列功能化共价有机框架材料（COFs）；通过研究COFs材料对锕系离子的吸附行为，建立COFs材料与吸附性能之间的构效关系，并提出从强酸性高放废液中分离锕系离子的解决方案；结合谱学手段和同步辐射技术，从分子水平揭示COFs材料对锕系离子的作用机制，为高放废液的处理处置提供新材料和新思路。

高放废液的处理处置是乏燃料后处理的中心环节，也是保障核安全的有效途径。而高放废液中锕系元素的的固相分离需要面对强酸性和强辐照的环境，这为材料的设计提出了很高的要求。为解决以上关键科学难题，我们通过合理的设计合成了一系列磷酸酯功能化的共价有机框架材料，该类材料表现出较好的酸碱稳定性和耐辐照特性。我们采用粉末衍射、固体核磁、红外光谱、元素分析、氮气吸脱附、扫描电镜并结合计算化学的方法对材料的结构和堆积方式进行了表征和模拟。吸附实验表明磷酸酯功能化的COFs材料对铀和钚表现出很好的吸附效果，特别是在强酸条件下仍然保持很高的吸附容量。我们首次实现了固相吸附材料在强酸条件下对锕系离子的吸附分离，而且循环数次后仍然保持较高的去除率。我们解决了长期以来固相功能材料在强酸条件下无法吸附分离锕系元素的难题，实现了重要的突破，也为其他锕系元素的分离提供了新材料和新思路。