基于仿生多巴胺化学构建氮杂氧膦配体功能化的磁性复合微球及其对镅的吸附性能研究

The efficient capture of americium from nuclear spent fuels is of great significance for the sustainable development of advanced nuclear fuel cycle. Recently, solid phase extraction has hold immense attention in the separation of americium. However, the reported sorbents always suffered from low adsorption capacity, unstable structure, long solid-liquid separation time and poor selectivity. Herein, in this study, the bioinspired polydopamine chemistry will be utilized for the first time to prepare Aza-phosphine oxide ligands functionalized magnetic composites, aiming for the rapid and efficient removal of americium from nuclear spent fuels. We will carefully evaluate the thermostability, acid resistance and radiation resistance of prepared magnetic composites, and investigate their adsorption behaviors toward americium in the aqueous solutions. It’s dedicated to establish a novel technology for the fabrication of organic ligands functionalized magnetic composites based on the polydopamine chemistry. The relationship between the controlled rule of dopamine self-polymerization, together with polydopamine structure and reaction activity will be discussed. Moreover, the coordination manner between different ligands and americium on the magnetic composites’ surface will be fully studied. Totally, this work will put forward new methods for preparing solid phase extraction materials of americium, and provide scientific supports for developing novel techniques for the separation and recovery of americium from nuclear spent fuels.

乏燃料中关键放射性核素镅的提取分离对于我国先进核燃料循环的可持续发展具有深远的战略意义。近年来，固相萃取技术已在镅的吸附分离方面展现出广阔的应用前景，但现有的吸附材料大多存在吸附容量低、结构不稳定、固液分离周期长、选择性差等缺陷。本项目拟将仿生多巴胺化学，首次应用于氮杂氧膦配体功能化的磁性复合微球的制备，以实现乏燃料中镅的快速、高效分离。项目将系统评估材料的热稳定性、耐酸性及抗辐照性，并研究其对水溶液中镅的吸附行为。项目将建立基于多巴胺化学构建有机配体功能化磁性复合材料的方法，探讨多巴胺自聚合过程的控制因素以及聚多巴胺结构同反应活性的关系，并深入研究固定于磁性微球表面的不同配体与镅的络合机制。本项目预期将为镅的固相萃取材料的制备提供新方法，同时为乏燃料中镅的分离回收技术的发展提供科学依据与技术支持。

放射性废液中锕系元素高效分离是乏燃料后处理的关键问题之一，对于资源回收复用及放射性废物处置具有重要意义。有机功能化固相吸附材料兼具有机配体的选择络合能力与基体材料的结构优势，具备从酸性且成分复杂的放射性废液中高效分离锕系元素的潜力。为此，本项目基于设计的氮杂氧膦配体，分别采用仿生多巴胺化学和辐照接枝的方法，构建了磁性仿生微球与烷基膦酸铪金属有机框架两种不同结构的复合吸附材料，并系统研究了其对水溶中U、Th、Np、Pu、Am吸附性能。研究结果表明，磁性仿生微球主要对弱酸性环境中锕系元素有较强吸附性能，且对Am、Pu的亲和力及选择性更佳，能在一定程度上实现放射性废液中Am、Pu的选择性分离与快速富集。烷基膦酸铪有机金属框架材料则对强酸性环境中锕系元素表现出优异的吸附性能，且在γ辐照处理后，吸附性能均有一定程度提升。此外，本项目还通过理论计算及光谱分析手段，深入探讨了两种材料与锕系元素配位络合机制。总体而言，相关研究工作建立了锕系元素固相吸附材料制备的新方法，为乏燃料中锕系元素的分离回收技术的发展提供科学依据与技术支持。