Metal-organic framework based membranes for selective separation of target ions.

Metal-organic frameworks (MOFs) are an increasingly popular class of porous materials due to their tailorable structure comprised of ordered porous cavities, high specific surface areas, and versatile functional organic ligands. Implementation of these porous materials into membrane separation technologies can create an energy-efficient alternative for ion-selective separation. However, their low stability in aqueous environments and other challenges has limited their industrial breakthrough. In the past five years, many developments have improved MOF-based membranes for the selective separation of target ions. Novel insight into MOF-based membranes' structure-property relationships improves dispersibility, stability, size-sieving, electrostatic repulsion, and ionic conductivity for ideal membrane performance. The latest design principles for MOF-based membrane use advanced confinement conversion, in situ self-assembly, layer-by-layer assembly, and interfacial polymerization methods for enhanced separation performance. Analysis of separation mechanisms in MOF-based membranes now extends applications to desalination, lithium extraction, removal of heavy metal ions, and separation of ions from organic solvents. Overall, further development of MOF-based membranes presents numerous opportunities and challenges in target ion separation. This review provides guidelines for the preparation methods and properties of MOF-based membranes for target ions separations. [Display omitted] • This review focused on the latest advancements in MOF-based membranes for selective separation of target ions. • The fundamental properties and novel design strategies for MOFs in ion separation were analyzed and concluded. • The theoretical simulations and separation mechanisms of ion transport in MOFs, were analyzed and concluded. • Applications in selective ion separation and future opportunities for MOF-based membranes were provided. [ABSTRACT FROM AUTHOR]