Xu Xiangmin, Zhu Xiaowei, Chen Jinchao, Zhang Xingran, Wang Zhiwei, Li Fang
College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; Shanghai Institution Pollution Control & Ecology Security, Shanghai 200092, China.
Water Res. 2025 Apr 15;274:123100. doi: 10.1016/j.watres.2025.123100. Epub 2025 Jan 5.
Ion selective membranes with precise Mg/Li separation have attracted extensive interest in lithium extraction to circumvent the lithium supply shortage. However, realizing this target remains a significant challenge mainly due to a high concentration ratio of Mg/Li as well as the relatively close ionic hydration radius and chemical. Herein, inspired by the host-guest recognition between alkali-metal ions and crown ether (CE), a novel approach was proposed to regulate the membrane internal structure by introducing CE to strengthen the complexation between Li and CE. The CE modified membranes achieved the unique outcome of "Li rejection-Mg permeation" deriving from enhanced solubility (K) and retarded diffusivity (D) of Li compared to that of Mg. The Mg/Li separation factors for MgSO/LiSO and MgCl/LiCl of modified membranes (i.e., 20.1 and 17.7) are about 21.9 and 19.9 time higher than that of pristine membranes, respectively. The results from density function theory (DFT) indicated that the stronger host-guest interaction between CE and Li combined them closely, thereby increasing solubility and reducing diffusivity of Li. Our findings develop a new efficient membrane-based strategy enabling the production of high-purity lithium salts from simulated brine.
具有精确镁锂分离功能的离子选择性膜在锂提取方面引起了广泛关注，以应对锂供应短缺的问题。然而，实现这一目标仍然是一项重大挑战，主要原因是镁锂浓度比高，以及离子水合半径和化学性质相对接近。在此，受碱金属离子与冠醚（CE）之间主客体识别的启发，提出了一种通过引入CE来调节膜内部结构的新方法，以加强锂与CE之间的络合作用。与镁相比，CE修饰的膜实现了锂溶解度增强（K）和扩散率降低（D）所带来的独特结果“锂截留-镁渗透”。修饰膜对硫酸镁/硫酸锂和氯化镁/氯化锂的镁锂分离因子（分别为20.1和17.7）分别比原始膜高约21.9倍和19.9倍。密度泛函理论（DFT）结果表明，CE与锂之间更强的主客体相互作用使它们紧密结合，从而提高了锂的溶解度并降低了其扩散率。我们的研究结果开发了一种基于膜的新型高效策略，能够从模拟卤水中生产高纯度锂盐。
