基于同步辐射X射线谱学新型硅基超分子杂化功能材料吸附放射性核素Cs-137的机制

Cs-137 is one of the radionuclide heat generators in spent nuclear fuel with a half-life of 30 years, which is of great concern in environment and human health. It exists in the form of cation with good solubility in aqueous solution and is easy to migrate, diffuse, and intake by organisms, resulting in more radiation damage. Thus, it is valuable to develop efficient methods to treat the radioactivie cesium. In terms of host-gust recognition and self-assembly technology, the present work will intend to design novel macrocyclic supramolecular derivatives and corresponding supramolecular hybrid materials with silica carrier for removing cesium pollutants from water environments based on screening the best known capturing materials. Then, the adsorption behaviors of cesium and other coexisted anions by supramolecular hybrid materials will be investigated, including the influence of temperature, concentration, pH values, contact time and so on. It aims to establish the relationship of structure-properties and propose a reasonable solution for deeply removing radioactive cesium pollutants from water environments. In terms of the X-ray absorption fine structure (XAFS) spectra of Shanghai Synchrotron Radiation Facility, the adsorption mechanism of cesium by supramolecular hybrid materials will be demonstrated with the help of supplementary traditional spectroscopy and single crystal X-ray diffraction techniques, which is extremely beneficial for further designing better supramolecular hybrid materials for cesium capturing.

Cs-137是核能发电过程中产生的一种高释热放射性核素，其半衰期为30年，具有较持久的放射性危害，易于在生物圈迁移扩散和被生物体吸收富集，造成辐射损伤。为降低水体中放射性铯污染含量，消除对人体健康的安全风险，研究有效去除铯污染处理方法具有重要价值。本项目拟基于主客体识别和自组装技术，通过结构调控设计新颖的大环超分子主体；依据非共价键相互作用及匹配原则，系统研究硅基超分子功能杂化材料对铯的吸附分离能力，筛选出最佳超分子功能杂化材料；考察该杂化材料吸附铯及典型共存离子性能和吸附分离技术可行性，明确温度、浓度、酸度和接触时间等因素变化对铯吸附分离的影响，建立构效关系；提出从放射性废水中去除铯污染物的解决方案。基于上海同步辐射光源的X射线吸收精细结构谱(XAFS)，并结合传统光谱和单晶X射线单晶衍射等表征方法，从宏观和微观上揭示硅基超分子杂化材料吸附分离铯的机制。

铯-137是乏燃料后处理过程中产生的高释热核素，其半衰期为30年，具有较持久的放射性危害，易于在生物圈迁移扩散和被生物体吸收富集，造成辐射损伤,对生态环境和人体健康具有潜在的危害性，研究其有效分离方法，明确分离机制，具有重要科学价值。本项目制备与表征了十余种超分子衍生物，通过工艺技术优化，建立了合成超分子衍生物技术路线；合成了以硅基超分子识别材料为代表的不同类型超分子识别杂化功能材料，在XRD、29Si CP/MAS NMR等手段表征其组成与结构基础上，依据非共价键相互作用及匹配原则，考察了硝酸溶液中超分子识别材料对铯及十余种典型共存元素的吸附特性，明确了温度、硝酸浓度和接触时间等因素变化对铯吸附性能的影响，研究了超分子识别材料的稳定性，获得了吸附分离铯最佳实验条件及重要参数。结果表明，硅基超分子识别材料吸附铯能力强、选择性高，基于此提出了从硝酸溶液中有效去除铯概念流程。通过X射线吸收精细结构谱(XAFS)及XPS和EDS等传统表征手段，揭示了硅基超分子识别材料吸附铯微观机制，明确了超分子衍生物与铯配位信息。