Lithium Extraction by Emerging Metal-Organic Framework-Based Membranes

Lithium is mainly extracted from brine and ores; however, current lithium mining methods require large amounts of chemicals, discharge many wastes, and can have serious environmental repercussions. Metal-organic framework (MOF)-based membranes have shown great potential in lithium extraction due to their uniform pore sizes, high porosities, and rich host-guest chemistry compared to other materials. In this review, the processes and disadvantages of current lithium extraction technologies are introduced. The structure features and corresponding design strategy of MOFs suitable for Li+ ion separations are presented. Following, recent advances of polycrystalline MOF membranes, mixed matrix membranes, and MOF channel membranes for lithium-ion separation are discussed in detail. Finally, opportunities for future developments and challenges in this emerging research field are presented.