Strategies for lithium extraction from salt lakes by nanofiltration and selective-electrodialysis and analysis of differences between the two methods

This review delves into the comparative analysis of nanofiltration (NF) and selective electrodialysis (S-ED) in the separation of Li+ and Mg2+ ions during lithium extraction from salt lakes. The examination is comprehensive, focusing on strategies to enhance selectivity in both methods. The paper outlines the selectivity mechanisms and then synthesizes approaches to improve the intrinsic selectivity of membranes (internal factors) and optimize process conditions (external factors). Moreover, it conducts a comparative analysis, evaluating the strengths, weaknesses, and separation efficiencies of both techniques. Comparative analyses were carried out to conclude that NF shows the higher selectivity relative to S-ED, while S-ED having a higher Li+ recovery than NF. Additionally, NF technology is more mature, due to that a variety of materials for NF membrane in the preparation process can be choosed . In contrast, the materials used for mono-/multi-valent separation cation exchange membranes (CEMs) are relatively limited, and their fabrication process requires higher precision. In conclusion, the review performs a thorough analysis and considers preparation techniques, operational conditions, and other factors on this basis. It proposes a developmental approach tailored to achieve high-selectivity Li+ recovery.