基于分子识别的冠醚功能化材料选择性吸附锂离子机制

It is important to research lithium recovery from spent lithium ion batteries for alleviating lithium resource crisis and achieving lithium resource recycling. At present, the lithium cannot be recycled from spent lithium ion batteries by pyrometallurgical processs. It is also difficult to effectively extract lithium by hydrometallurgical process because of the low concentration of Li+ and the effects of impurity elements. Based on the principle of molecular recognition, 15-crown-5 crown ether with different electron-donating groups grafted nano Fe3O4@SiO2（FS-g-15C5-R）will be prepared to adsorb the lithium ions selectively, and a new method for lithium recovery in the hydrometallurgical process of spent lithium ion batteries will be established in this project. The recognition mechanism of 15C5-R on lithium ions and the synergistic coordination effect of side-arm groups will be revealed by research on the coordination mechanism of 15C5-R with Li+、Co2+ and Ni2+. The adsorption behavior of FS-g-15C5-R to Li+ in solution will be carried out to clarify the thermodynamics and kinetics of the adsorption process. The results of above researches will reveal the selective adsorption mechanism of Li+ and provide a theoretical basis for the lithium recovery from the spent lithium-ion batteries leaching solution after removing cobalt. The successful implementation of this project will be of great practical significance and scientific value for promotion of the lithium recycling and enriching the basic theory of host-guest chemistry.

开展从废旧锂离子电池中回收锂的研究对缓解我国锂资源危机，实现锂资源循环具有重要意义。目前火法工艺难以回收废旧锂离子电池中的锂，而湿法工艺中由于Li+浓度低，且存在杂质元素影响，也难以有效提取。本项目基于分子识别原理，拟设计合成一种对锂离子具有选择性吸附作用的新型吸附剂：15-冠-5冠醚衍生物功能化纳米Fe3O4@SiO2（FS-g-15C5-R），建立从废旧锂离子电池湿法处理过程回收锂的新方法。通过对15C5-R与Li+、Co2+、Ni2+的配位机理研究，揭示其对锂离子的识别机理及侧臂基团的协同配位效应。开展FS-g-15C5-R对溶液中Li+的吸附行为研究，阐明吸附过程热力学及动力学。综上结果，揭示吸附剂对溶液中Li+的选择性吸附机制，为从废旧锂离子电池浸出液除钴后液中选择性高效回收锂提供理论基础。本项目的成功实施对于推动锂资源回收，丰富主客体化学的基础理论具有重要的现实意义及科学价值。

开展从废旧锂离子电池中回收锂的研究对缓解我国锂资源危机，实现锂资源循环具有重要意义。目前火法工艺难以回收废旧锂离子电池中的锂，而湿法工艺中由于Li+浓度低，且存在杂质元素影响，也难以有效提取。本项目基于分子识别原理，首先选择了两种对溶液中Li+具有选择性识别能力的冠醚化合物B15C5和DB14C4。随后以邻苯二酚和二乙二醇双-(2-氯乙基)醚为原料在正丁醇溶剂中合成了B15C5，以邻苯二酚和1,3-二溴丙烷为原料在异戊醇溶剂中合成了DB14C4，对产物进行了FTIR、1H NMR及质谱分析，确认了产物结构，并开展了液液萃取实验研究。详细考察了pH值、温度及萃取时间对Li+萃取效果的影响。结果发现B15C5具有更佳的Li+选择能力，其中Li+/Co2+和Li+/Ni2+的分离系数分别达到226.40和48.08，而对Mn2+则未表现出萃取能力。采用量子化学计算，从结合能、静电势、几何结构、热力学等角度进行分析，阐明了B15C5对Li+的选择性识别机理。本项目的研究为从废旧锂离子电池浸出液中选择性高效回收锂提供了理论基础，对于推动锂资源回收，丰富主客体化学的基础理论具有重要的现实意义及科学价值。