This study aims to fabricate monovalent cations selective membranes through Layer-by-Layer (LbL) assembly with ion-imprinting introduced. Nickel ions (Ni²⁺) were introduced into the polycation of polyethyleneimine (PEI) as template and then modified the ultrafiltration membrane through LbL assembly followed by glutaraldehyde (GA) crosslinking and reduction. After eluting the template, ion-imprinting channels with specific size were formed in the modified layer. These channels enhanced the water flux with the selectivity for Na⁺/Mg²⁺ improved 2.25 times simultaneously compared to the non-imprinted membrane. Besides, the membrane preparation conditions were optimized and the optimum selectivity of 4.16 was achieved. We analyzed the mechanism of improving separation performance via ion-imprinting technology and believed that this environmental-friendly method provides a new road to fabricate monovalent selective membrane for seawater softening and lithium extraction from magnesium-rich brine.

本研究旨在通过引入离子印迹的逐层 (LbL) 组装制备单价阳离子选择性膜。将镍离子（Ni ²⁺）作为模板引入聚乙烯亚胺（PEI）的聚阳离子中，然后通过LbL组装修饰超滤膜，然后戊二醛（GA）交联和还原。洗脱模板后，在改性层中形成特定尺寸的离子印迹通道。^{这些通道通过对 Na +} /Mg ²⁺的选择性提高了水通量与非印迹膜相比，同时提高了 2.25 倍。此外，对膜制备条件进行了优化，达到了4.16的最佳选择性。我们分析了离子印迹技术提高分离性能的机理，认为这种环境友好的方法为制备用于海水软化和富镁卤水提锂的单价选择性膜提供了一条新途径。