Highly Cation Permselective Metal–Organic Framework Membranes with Leaf‐Like Morphology. Issue 12 (27th May 2019)

• Record Type: Journal Article
• Authors: Xu, Tingting; Shehzad, Muhammad A.; Yu, Dongbo; Li, Qiuhua; Wu, Bin; Ren, Xuemei; Ge, Liang; Xu, Tongwen
• Is Part Of: ChemSusChem. Volume 12:Issue 12(2019)
• Page Start: 2593
• Page End: 2597
• Publication Date: 2019-05-27
• Subjects: ion separation -- metal extraction -- membranes -- metal–organic frameworks -- porous materials; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201900706
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: Highly cation permselective metal–organic framework (MOF) membranes are desirable for the extraction of valuable metal cations. However, fabrication of defect‐free and stable permselective MOF membranes is technically challenging, owing to their arduous self‐assembly and poor water resistance, respectively. A simple and readily scalable method has been developed for the controlled in situ smart growth of UiO‐66‐NH2 into leaf‐like nanostructures with tunable density of the leaves and the surface layer thickness. The self‐assembly approach reproducibly fabricates seamless, ultrathin (<500 nm) UiO‐66‐NH2 membranes at the surface of anodic aluminum oxide. The membranes contain nanosized interstices among the MOF leaves, which enable maximum admission of ions within the membrane, and angstrom‐sized inherent pores in every single UiO‐66‐NH2 crystal, which efficiently regulate the cation permselectivity. Consequently, the highest ever reported cation separations (Na + /Mg 2+ >200 and Li + /Mg 2+ >60) and excellent membrane stability during five sequential electrodialysis cycles are achieved. These characteristics position the fabricated MOF membranes as potential candidates for efficient extraction of pure lithium and sodium ions from salt lakes and seawater, respectively. Abstract : Hail to the leaf : Leaf‐like UiO‐66‐NH2 membranes are fabricated, containing nanosized interstices among the "leaves", which enable maximum admission of ions within the membrane, and angstrom‐sized inherent pores in every single crystal, which efficiently regulate the cation permselectivity (Na + /Mg 2+ >200 and Li + /Mg 2+ >60). The excellent membrane stability ensures the MOF membranes are a potential candidate for cation separation.