Mo Ri-Jian, Chen Shuang, Huang Li-Qiu, Ding Xin-Lei, Rafique Saima, Xia Xing-Hua, Li Zhong-Qiu
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 210023, Nanjing, China.
Nat Commun. 2024 Mar 8;15(1):2145. doi: 10.1038/s41467-024-46378-6.
Membrane consisting of ordered sub-nanochannels has been pursued in ion separation technology to achieve applications including desalination, environment management, and energy conversion. However, high-precision ion separation has not yet been achieved owing to the lack of deep understanding of ion transport mechanism in confined environments. Biological ion channels can conduct ions with ultrahigh permeability and selectivity, which is inseparable from the important role of channel size and "ion-channel" interaction. Here, inspired by the biological systems, we report the high-precision separation of monovalent and divalent cations in functionalized metal-organic framework (MOF) membranes (UiO-66-(X), X = NH, SH, OH and OCH). We find that the functional group (X) and size of the MOF sub-nanochannel synergistically regulate the ion binding affinity and dehydration process, which is the key in enlarging the transport activation energy difference between target and interference ions to improve the separation performance. The K/Mg selectivity of the UiO-66-(OCH) membrane reaches as high as 1567.8. This work provides a gateway to the understanding of ion transport mechanism and development of high-precision ion separation membranes.
在离子分离技术中，由有序亚纳米通道组成的膜被用于实现包括海水淡化、环境管理和能量转换在内的应用。然而，由于对受限环境中离子传输机制缺乏深入了解，尚未实现高精度的离子分离。生物离子通道能够以超高的渗透率和选择性传导离子，这与通道尺寸和“离子-通道”相互作用的重要作用密不可分。在此，受生物系统启发，我们报道了在功能化金属有机框架（MOF）膜（UiO-66-(X)，X = NH、SH、OH和OCH）中实现单价和二价阳离子的高精度分离。我们发现，MOF亚纳米通道的官能团（X）和尺寸协同调节离子结合亲和力和脱水过程，这是扩大目标离子和干扰离子之间的传输活化能差以提高分离性能的关键。UiO-66-(OCH)膜的K/Mg选择性高达1567.8。这项工作为理解离子传输机制和开发高精度离子分离膜提供了一条途径。
