Abstract Lithium extraction from brines with the high Mg2+/Li+ ratio is crucial for sustainable lithium resource and environmental protection. This study incorporated the classic tributylphosphate (TBP)/FeCl3 system into the polyvinyl chloride (PVC) based polymer inclusion membrane (PIM) to extract Li+ from the solution which is rich of Mg2+ (The initial Mg2+/Li+ molar ratio is 15). The morphology and composition of PIMs were characterized systematically, and the content of TBP/FeCl3 carrier in the PIM was optimized. Compared to liquid-liquid extraction, the extraction ratio of Li+ for PIM extraction increases by 20% and the separation factor of Li+ over Mg2+ increases by 5%. Besides, the loss ratio of Fe3+ after one loop of liquid-liquid extraction is 17.79%, which is close to that of PIM extraction after three loops (18.30%), demonstrating that the PIM showed a good stability. Furthermore, the separation factor of Li+ over Mg2+ for the PIM with 50 wt% TBP/FeCl3 is as high as 176 and the initial flux for Li+ is 8.12 × 10−4 mol m−2 h−1. This study displays a TBP/FeCl3 based PIM with high selectivity for Li+, providing a possible membrane technology for lithium extraction from brines.

中文翻译：

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使用聚合物包裹膜从高 Mg2+/Li+ 比的合成盐水中提取锂

摘要 从高 Mg2+/Li+ 比的卤水中提取锂对于锂资源的可持续发展和环境保护至关重要。本研究将经典的磷酸三丁酯 (TBP)/FeCl3 系统纳入聚氯乙烯 (PVC) 基聚合物包裹膜 (PIM)，以从富含 Mg2+ 的溶液中提取 Li+（初始 Mg2+/Li+ 摩尔比为 15）。系统地表征了 PIMs 的形貌和组成，并优化了 PIM 中 TBP/FeCl3 载体的含量。与液液萃取相比，PIM萃取Li+的萃取率提高了20%，Li+相对于Mg2+的分离系数提高了5%。此外，一循环液液萃取后Fe3+的损失率为17.79%，接近三循环后PIM萃取的损失率（18.30%），表明 PIM 表现出良好的稳定性。此外，对于含有 50 wt% TBP/FeCl3 的 PIM，Li+ 与 Mg2+ 的分离因子高达 176，Li+ 的初始通量为 8.12 × 10-4 mol m-2 h-1。该研究展示了一种基于 TBP/FeCl3 的 PIM，对 Li+ 具有高选择性，为从盐水中提取锂提供了一种可能的膜技术。