Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Molecules. 2019 Jul 30;24(15):2762. doi: 10.3390/molecules24152762.
The adsorption of lithium ions(Li) and the separation of lithium isotopes have attracted interests due to their important role in energy storage and nuclear energy, respectively. However, it is still challenging to separate the Li and its isotopes with high efficiency and selectivity. A novel cellulose-based microsphere containing crown ethers groups (named as MCM--AB15C5) was successfully synthesized by pre-irradiation-induced emulsion grafting of glycidyl methacrylate (GMA) and followed by the chemical reaction between the epoxy group of grafted polymer and 4'-aminobenzo-15-crown-5 (AB15C5). By using MCM--AB15C5 as adsorbent, the effects of solvent, metal ions, and adsorption temperature on the adsorption uptake of Li and separation factor of Li/Li were investigated in detail. Solvent with low polarity, high adsorption temperature in acetonitrile could improve the uptake of Li and separation factor of lithium isotopes. The MCM--AB15C5 exhibited the strongest adsorption affinity to Li with a separation factor of 1.022 ± 0.002 for Li/Li in acetonitrile. The adsorption isotherms in acetonitrile is fitted well with the Langmuir model with an ultrahigh adsorption capacity up to 12.9 mg·g, indicating the unexpected complexation ratio of 1:2 between MCM--AB15C5 and Li. The thermodynamics study confirmed the adsorption process is the endothermic, spontaneous, and chemisorption adsorption. As-prepared novel cellulose-based adsorbents are promising materials for the efficient and selective separation of Li and its isotopes.
锂离子（Li）的吸附和锂同位素的分离因其在储能和核能方面的重要作用而受到关注。然而，高效和选择性地分离 Li 和其同位素仍然具有挑战性。通过预辐射引发的甲基丙烯酸缩水甘油酯（GMA）乳液接枝，然后接枝聚合物的环氧基团与 4'-氨基苯并-15-冠-5（AB15C5）发生化学反应，成功合成了一种含有冠醚基团的新型纤维素基微球（命名为 MCM--AB15C5）。使用 MCM--AB15C5 作为吸附剂，详细研究了溶剂、金属离子和吸附温度对 Li 吸附量和 Li/Li 分离因子的影响。在乙腈中，低极性溶剂和高吸附温度可以提高 Li 的吸附量和锂同位素的分离因子。MCM--AB15C5 对 Li 表现出最强的吸附亲和力，在乙腈中 Li/Li 的分离因子为 1.022±0.002。在乙腈中的吸附等温线与 Langmuir 模型拟合良好，吸附容量高达 12.9mg·g-1，表明 MCM--AB15C5 与 Li 之间具有出乎意料的 1:2 复杂比。热力学研究证实吸附过程是吸热、自发和化学吸附过程。所制备的新型纤维素基吸附剂有望成为高效和选择性分离 Li 和其同位素的材料。
