Enhanced cation sieving selectivity is significant for polyamide (PA) nanofiltration membrane in terms of extracting lithium from Salt Lake brines, which enable to reduce production cost and operating energy consumption. Herein, an aliphatic PA nanofilm with ordered nanostripe was fabricated using a novel distorted and non-coplanar monomer, cyclopentane tetracarboxylic acid chloride (CPTC). Because of the fine-tuning of the dendrimer porous layer, the resultant aliphatic PA membrane revealed decreased thickness in separation layer, and an enhanced synergistic effect of size exclusion and Donnan equilibrium on mono-/divalent cation. Separation experiments indicated that a higher MgCl₂ rejection (up to 98.36%) and a lower LiCl rejection (33.3%) were obtained, thus achieving a good cation selectivity (48.25 for Na⁺/Mg²⁺, 36.5 for Li⁺/Mg²⁺). This result was better compared with the full-aromatic and most of the literature reported positive charged PA membranes. Moreover, water flux of the CPTC–tris(2-aminoethyl) amine (TAEA) membrane with nanostripe structure (N-CPTC–TAEA) increased 3.98–4.74 times (for example, 135.9 ± 4.62 for 2000 ppm LiCl) that of the CPTC–TAEA membrane. Meanwhile, the N-CPTC–TAEA also exhibited a better antifouling property than that of the full-aromatic membrane. This study demonstrates that the N-CPTC–TAEA tends to be an alternative membrane material for cation separation.

增强的阳离子筛分选择性对于聚酰胺（PA）纳滤膜在从盐湖卤水中提取锂具有重要意义，可以降低生产成本和运行能耗。在此，使用新型扭曲和非共面单体环戊烷四羧酸氯化物 (CPTC) 制备了具有有序纳米条的脂肪族 PA 纳米膜。由于树枝状大分子多孔层的微调，所得脂肪族 PA 膜的分离层厚度降低，尺寸排阻和 Donnan 平衡对一价/二价阳离子的协同作用增强。分离实验表明，较高的 MgCl ₂截留率（高达 98.36%）和较低的 LiCl 截留率（33.3%），从而实现了良好的阳离子选择性（Na ⁺ /Mg ²⁺为 48.25 ，Li ⁺ /Mg ²⁺为 36.5 ）。与全芳族和大多数文献报道的带正电荷的 PA 膜相比，该结果更好。此外，具有纳米条结构的 CPTC-三（2-氨基乙基）胺（TAEA）膜（N-CPTC-TAEA）的水通量比 CPTC 增加了 3.98-4.74 倍（例如，2000 ppm LiCl 为 135.9 ± 4.62） -TAEA 膜。同时，N-CPTC-TAEA也表现出比全芳族膜更好的防污性能。这项研究表明，N-CPTC-TAEA 往往是阳离子分离的替代膜材料。