碳基超分子杂化材料吸附铯的性能与作用机理研究

The separation of heat emitting nuclide Cs(I) is of great significance for the safe disposal of high level radioactive liquid waste (HLLW) and is one of the hot research focus and critical difficult problems in the area of nuclear fuel cycle. On the assumption of remaining the macro-mesoporous structure, the calix[4]arene-mono/bis-crown-6 will be directionally functionalized onto the pore surface of millimetre-sized macro-mesoporous carbon sphere (MMCS) with hierarchical pores, large specific surface area and pore volume to prepare novel carbon-based supramolecule hybrid materials with high adsorption capacity, strong selectivity and stability by self-assemble technology in view of solving the weak bonding between supramolecule and matrix, low loading amount, poor radiation resistant and chemical stability. The effect of self-assemble conditions on the adsorption properties and microstructures will be studied, and the relationship between structures and sorption properties will be explored. The existing state of cesium on the hybrid material will be studied at the molecular level by advanced spectroscopic analysis methods (XPS and EXAFS) and theoretical calculation in order to confirm the sorption mechanism of cesium on the hybrid material. Additionally, the application research of separating cesium from simulated HLLW will be investigated. The expected research outputs will provide theoretical and technical supports to separate cesium from HLLW effectively.

发热核素铯的高效分离对高放废液的安全处理与处置具有重要意义，是核燃料循环领域研究的热点和亟需攻克的难题之一。本项目以孔结构丰富、比表面积和孔容大的毫米级大孔-有序介孔碳球（毫米级碳球）为基体，采用自组装杂化技术，在保留大孔和介孔结构的前提下，将杯[4]芳烃-单/双-冠-6定向功能化至毫米级碳球的孔壁上，制备吸附容量大、选择性高和稳定性强的新型碳基超分子杂化材料，解决超分子与基体结合不牢固、负载量小、耐辐照和化学稳定性差等问题。重点研究杂化工艺参数对碳基超分子杂化材料微观结构和吸附性能的影响，探讨碳基超分子杂化材料吸附铯的构效关系；结合XPS和EXAFS等先进谱学手段和理论计算，从原子分子水平研究铯在材料表面的赋存状态，阐明碳基超分子杂化材料吸附铯的作用机理，并开展碳基超分子杂化材料吸附分离模拟高放废液中铯的应用研究。本项目预期研究成果将为高放废液中高效吸附分离铯提供理论和技术支持。

发热核素铯的高效分离对高放废液的安全处理与处置具有重要意义，是核燃料循环领域研究的热点和亟需攻克的难题之一。本项目以孔结构丰富、比表面积和孔容大的毫米级大孔-有序介孔碳球（毫米级碳球）为基体，采用自组装杂化技术，在保留大孔和介孔结构的前提下，将杯[4]芳烃-双冠-6定向功能化至毫米级碳球的孔壁上，制备吸附容量大、选择性高和稳定性强的新型碳基超分子杂化材料，解决超分子与基体结合不牢固、负载量小、耐辐照和化学稳定性差等问题。Calix[4]BisC6/MMCs-P、Calix[4]C6BenC6/MMCs-P和Calix[4]C6TBuC6/MMCs-P的吸附平衡时间分别为180、210和150 min，吸附铯的最大分配系数高达225.8、105.78和85.08 mL·g-1，除Cs+和Rb+以外，对其他金属离子几乎不吸附，对Cs+和Rb+(SF(Cs/Rb))的分离系数分别达到5.8、18.49和21.45。Calix[4]BisCrowns/MMCs-P 吸附Cs(I)的行为符合准二级动力学模型和Langmuir等温模型，Calix[4]BisCrowns/MMCs-P吸附Cs(I)是化学吸附、放热、自发的过程。本项目的研究成果为从 HLLW 复杂体系中高选择性吸附分离 Cs(I)提供理论和技术支持，为HLLW中Cs(I)的高效分离提供新材料、新技术和新方法，为高放废液的安全处理与处置添砖加瓦。