Lattice-defective metal-organic framework membranes from filling mesoporous colloidal networks for monovalent ion separation

• Published in: Journal of membrane science 2025-02, Vol.715, p.123508, Article 123508
• Main Authors: Xiao, Yihao, Yu, Yanqing, Huang, Xinxi, Niu, Kun, Li, Wanbin
• Format: Article
• Language: English
• Subjects: Interior growth; Lattice defects; Membrane separation; Mesoporous colloids; Metal-organic frameworks
• ISSN: 0376-7388
• DOI: 10.1016/j.memsci.2024.123508

Ionic separations are critical to various chemical, environmental, and energy-related industries, but precise discrimination of monovalent ions with similar properties is extremely difficult. Nanoporous metal-organic framework (MOF) membranes attract intensive attention for ionic separations. However, precise adjusting transport nanochannels of frameworks and simplifying formation mechanisms of membranes remain extremely challenging. In this study, we report controllable construction of lattice-defective MOF membranes for sharp ion sieving, through filling mesoporous MOF colloidal layers by confined interior growth. By utilizing highly processable mesoporous colloidal networks to provide abundant nucleation sites, decelerate precursor diffusions, and serve as membrane-forming hosts, interior MOF growth can be confined in the mesopores of hosts, thereby eliminating any avoid spaces and constructing pinhole-free membranes in a scalable route. Moreover, through creating linker-missing lattice defects in frameworks, the microporous pathways can be accurately expanded at angstrom level, consequently, selectively improving the accessibilities for specific monovalent cations but maintaining the large resistances for others. Importantly, the prepared 150-nm MOF membranes exhibit good long-term stability and superb ion-sieving performance, especially for monovalent cations, with mixture selectivities as high as 7.5 for K+/Li+ and 51 for K+/Mg2+ during concentration-driven separations, which outperform most membranes. This study provides an alternative methodology to construct high-performance ion-sieving polycrystalline membranes. [Display omitted] •Lattice-defective UiO-66 membranes are constructed for monovalent ionic separation.•Mesoporous colloids improve nucleation, control diffusion, and serve as hosts.•UiO-66 membranes are formed by interior MOF growth filling mesoporous colloid hosts.•Lattice defects precisely tune pathways and reduce resistance for specific cations.•UiO-66 membranes show mixture selectivities up to 7.5for K+/Li+ and 51 for K+/Mg2+.