Selective lithium recovery from salt lake brine using emerging nanofiltration membranes is expected to solve the insufficient supply of lithium resources. In this work, 1,4,7,10-tetraazacyclododecane (Cyclen) was employed as a novel structural regulator through interfacial polymerization of polyethyleneimine (PEI) and trimesoyl chloride (TMC) to develop polyamide NF membrane with efficient Li⁺/Mg²⁺ separation performance. After the introduction of Cyclen to aqueous phase, the PEI/Cyclen-TMC selective layer was confirmed to possess a higher crosslinking degree and larger d-spacing than PEI-TMC layer, endowing a dedicated channel for Li⁺ transport. The water permeance of PEI/Cyclen-TMC composite membrane reached 14.0 L·m⁻²·h⁻¹·bar⁻¹, about 3.8 times higher than PEI-TMC composite membrane, and meanwhile the separation factor (S_Li,Mg) could be stabilized as 8.7 to realize a considerable reduction of Mg²⁺/Li⁺ mass ratio from 20 to 2.3. Additionally, PEI/Cyclen-TMC composite membrane was utilized to operate a three-stage nanofiltration treatment procedure of a simulated salt lake brine (Mg²⁺/Li⁺ mass ratio: 40). The results indicated that Li⁺ could be efficiently retracted to obtain a solution with 19.5 mg·L⁻¹ Li⁺ and Mg²⁺/Li⁺ mass ratio of 0.3. After the subsequent precipitation and filtration, the obtained Li₂CO₃ purity could reach 93 %, indicating the potential application of nanofiltration for lithium recovery.

利用新兴的纳滤膜从盐湖卤水中选择性回收锂有望解决锂资源供应不足的问题。在这项工作中，1,4,7,10-四氮杂环十二烷 (Cyclen) 通过聚乙烯亚胺 (PEI) 和均苯三甲酰氯 (TMC) 的界面聚合被用作新型结构调节剂，以开发具有高效 Li + /Mg 2+ 的^聚酰胺纳^滤膜分离性能。在将 Cyclen 引入水相后，PEI/Cyclen-TMC 选择性层被证实具有比 PEI-TMC 层更高的交联度和更大的 d 间距，为 Li + 传输提供了专用^通道。PEI/Cyclen-TMC复合膜的透水量达到14.0 L·m ^-2 ·h⁻¹ ·bar ⁻¹，比PEI-TMC复合膜高约3.8倍，同时分离因子（S _Li,Mg）可以稳定在8.7，实现Mg ²⁺ /Li ⁺质量比从20大幅降低到 2.3。^{此外，利用PEI/Cyclen-TMC复合膜对模拟盐湖卤水（Mg 2+} /Li ⁺质量比：40）进行三级纳滤处理。结果表明，Li ^{+可以有效地缩回以获得具有19.5 mg·L −1} Li ⁺和Mg ²⁺ /Li ⁺的溶液质量比为0.3。经过后续的沉淀和过滤后，得到的Li ₂ CO ₃纯度可达93%，表明纳滤在锂回收方面具有潜在的应用前景。