Although nanofiltration (NF) membrane as a new frontier technique had made significant progress in the field of lithium extraction from salt lakes, they still suffered from the conventional permeability–selectivity trade-off effect. In this study, γ-cyclodextrins(CDs) containing amphipathic cavities and polyethyleneimine (PEI) acted as the aqueous phase monomer, which was carried out interfacial polymerization with the trimesoyl chloride (TMC) as the organic phase monomer to fabricate thin film composite (TFC) NF membranes with the extra-thin active layer. The hydrophilic surface and hydrophobic cavity of γ-CDs enhanced the hydrophilicity of the membrane surface and the water flux of the nanofiltration membrane. Moreover, the cavity size of γ-CDs also effectively screened magnesium and lithium ions to a certain extent. Under the best preparation conditions, the permeation flux of the PEI/γ-CDs-TMC nanofiltration membrane was 4.86 L⋅m⁻²⋅h⁻¹⋅bar⁻¹, S_{Li, Mg} was 10.8. It was noteworthy that we used the molecular dynamics simulation method to confirm that the participation of γ-CDs led to the diffusion rate of the water phase monomers during the interfacial polymerization reaction slowed down. Thus, the thickness of the active layer of the nanofiltration membrane formed was also significantly reduced from 110.16 nm to 52.84 nm. This PEI/γ-CDs-TMC membrane provided a new strategy for preparing nanofiltration membranes with excellent overall magnesium-lithium separation performance.

尽管纳滤（NF）膜作为一种新的前沿技术在盐湖提锂领域取得了重大进展，但仍存在传统的渗透率-选择性权衡效应。本研究以含有两亲空腔的γ-环糊精(CDs)和聚乙烯亚胺(PEI)为水相单体，以均苯三甲酰氯(TMC)为有机相单体进行界面聚合制备薄膜复合材料(TFC)。 ) 具有超薄活性层的 NF 膜。γ-CDs的亲水表面和疏水腔增强了膜表面的亲水性和纳滤膜的水通量。此外，γ-CDs的空腔尺寸也在一定程度上有效地屏蔽了镁离子和锂离子。^-2 ⋅h ^-1 ⋅bar ^-1 , S _{Li, Mg}为 10.8。值得注意的是，我们使用分子动力学模拟方法证实，γ-CDs的参与导致界面聚合反应过程中水相单体的扩散速率减慢。因此，所形成的纳滤膜的活性层厚度也由110.16 nm显着降低至52.84 nm。这种PEI/γ-CDs-TMC膜为制备具有优异整体镁锂分离性能的纳滤膜提供了新的策略。