LAUSR

Abstract Lithium procurement has become a worldwide policy due to the rapid development of Lithium Ion Batteries. However, during its extraction from natural sources, Li+/Na+ separation remains challenging due to its similar characteristics. Herein, we investigate the Li+/Na+ separation by two selective and environmentally friendly processes, diffusion dialysis (DD) and cross ion dialysis (CID), using Lithium Composite Membrane (LCM). Firstly, we studied the effect of several experimental parameters by DD (pH, co-ion nature, feed solution composition, treatment duration) and by CID (compositions of feed and receiver) on Li+ diffusion through LCM.DD results have shown that Li+ recovery rate reaches 22.1% of its initial feed concentration after 27 days of treatment, which is very efficient compared to the evaporation process. CID obtained results reveal that optimal Li+ diffusion is achieved at 0.1 M HCl. Secondly, we examined the effect of [Na+]F/[Li+]F ratio in the feeding solution on membrane performances (recovered Li+ concentration, selectivity coefficient S(Li+/Na+) and recovery rate) by DD and CID. It was found that high recovered Li+ concentration was reached even at high ratio. At [Na+]F/[Li+]F = 40 and after 24 h of treatment, we successfully extract 16.63% of Li+ with only 0.003% of Na+ and S(Li+/Na+) = 5543 by DD and 36.78% of Li+ with only 0.11% of Na+ and S(Li+/Na+) = 931 by CID. Finally, the reusability of LCM during DD was evaluated using two regeneration protocols, one with pure water and the other with a 0.1 M LiCl solution. Results reveal that the second protocol shows better preservation of the membrane selectivity. Thus, LCM is suitable for lithium recovery from its low-concentration sources (brines and seawater).