Highly Ion-Permselective Porous Organic Cage Membranes with Hierarchical Channels

• DOI: 10.1021/jacs.2c00318
• Publication Date: 2022-05-19T07:06:34Z
• Authors: Tingting Xu; Bin Wu; Linxiao Hou; Yanran Zhu; Fangmeng Sheng; Zhang Zhao; Yun Dong; Jiandang Liu; Bangjiao Ye; Xingya Li; Liang Ge; Huanting Wang; Tongwen Xu
• Keywords: Cage

Membranes of high ion permselectivity are significant for the separation species at subnanometer scale. Here, we report porous organic cage (i.e., CC3) membranes with hierarchical channels including discrete internal cavities and cage-aligned external connected by subnanometer-sized windows. The windows CC3 sieve monovalent ions from divalent ones dual nanometer-sized provide pathways fast transport a flux 1.0 mol m-2 h-1 mono-/divalent selectivity (e.g., K+/Mg2+) up to 103, several orders magnitude higher than permselectivities reported membranes. Molecular dynamics simulations illustrate trajectory cavity via window, where migrate in diverse hydration states following energy barrier sequence K+ < Na+ Li+ ≪ Mg2+. This work sheds light on properties frameworks offers guidelines developing efficient separation.