Meng Qing-Wei, Li Jianguo, Xing Zhiwei, Xian Weipeng, Lai Zhuozhi, Dai Zhifeng, Wang Sai, Zhang Li, Yin Hong, Ma Shengqian, Sun Qi
Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
ACS Nano. 2025 Apr 1;19(12):12080-12089. doi: 10.1021/acsnano.4c18135. Epub 2025 Mar 18.
The strategic spatial positioning of ion affinity sites within biological ion channels and their cooperative binding with the targeted ions are pivotal for enhancing ion recognition and ensuring exceptional selectivity in high ionic competition scenarios. However, the application of these principles to artificial ion channels remains largely unexplored. Herein, we present a series of covalent organic framework (COF) membranes, engineered with oxygen functional groups aligned along the rims of oriented COF pore channels of varying sizes to achieve a precise spatial arrangement of ion affinity sites. A notable COF membrane, featuring subnanometer pores decorated alternately with carbonyl and amide groups, demonstrated outstanding selectivity, achieving a Li/Mg selectivity ratio of 513 under equal mole and electrodialysis conditions. Impressively, as the Mg/Li ratio in the source solution increased to 16.6, the selectivity ratio rose to 833, significantly exceeding the reductions typically seen in conventional selective electrodialysis and nanofiltration methods. Both simulation and experimental analyses indicate that this exceptional selectivity stems from the cooperative binding between the oxygen functional groups and Li ions within the confined nanochannels, facilitating the preferential transport of Li ions. These findings provide a promising approach for designing selective ion extraction systems that function effectively in highly competitive environments.
生物离子通道内离子亲和位点的战略空间定位及其与目标离子的协同结合，对于增强离子识别以及在高离子竞争场景中确保卓越的选择性至关重要。然而，这些原理在人工离子通道中的应用在很大程度上仍未得到探索。在此，我们展示了一系列共价有机框架（COF）膜，通过沿不同尺寸的定向COF孔道边缘排列氧官能团进行工程设计，以实现离子亲和位点的精确空间排列。一种显著的COF膜，具有交替装饰有羰基和酰胺基团的亚纳米孔，表现出出色的选择性，在等摩尔和电渗析条件下实现了513的Li/Mg选择性比。令人印象深刻的是，随着源溶液中Mg/Li比增加到16.6，选择性比升至833，显著超过了传统选择性电渗析和纳滤方法中通常出现的降低程度。模拟和实验分析均表明，这种卓越的选择性源于受限纳米通道内氧官能团与锂离子之间的协同结合，促进了锂离子的优先传输。这些发现为设计在高度竞争环境中有效运行的选择性离子提取系统提供了一种有前景的方法。
