Lyu Bohui, Jiang Jianwen, Jiang Zhongyi
Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, China.
Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, 117576, Singapore.
Small Methods. 2025 Apr;9(4):e2401537. doi: 10.1002/smtd.202401537. Epub 2024 Dec 31.
3D covalent-organic framework (3D COF) membranes have unique features such as smaller pore sizes and more interconnected networks compared with 2D COF counterparts. However, the complicated and unmanageable fabrication hinders their rapid development. Molecular simulation, which can efficiently explore the structure-performance relationship of membranes, holds great promise in accelerating the development of 3D COF membranes. In this study, a series of 3D-COF membranes (TFPM-Pa-X) is designed with different charge densities (fully charged, partially charged, and neutral) and interpenetration numbers (2-, 3-, 4-, and 5-fold), subsequently investigate their contributions to Li/Mg separation through molecular simulation. Membrane morphology and pore size are found to strongly depend on the charged density and interpenetration number. The pore size and Cl ion density play a crucial role in governing membrane separation performance. TFPM-Pa-X membrane with a smaller interpenetration number and a higher charge density promotes Li/Mg separation. The fully charged 2-fold interpenetrated membrane has superior performance in breaking the trade-off between the flux of Li (J ) and the selectivity of Li over Mg (S ). This study may facilitate the rational design of new 3D COF membranes for high-performance ion separation.
与二维共价有机框架（2D COF）膜相比，三维共价有机框架（3D COF）膜具有孔径更小、网络互连性更强等独特特性。然而，其复杂且难以控制的制备过程阻碍了它们的快速发展。分子模拟能够有效探索膜的结构-性能关系，在加速3D COF膜的发展方面具有巨大潜力。在本研究中，设计了一系列具有不同电荷密度（全电荷、部分电荷和中性）和互穿数（2、3、4和5重）的3D-COF膜（TFPM-Pa-X），随后通过分子模拟研究它们对锂/镁分离的贡献。发现膜的形态和孔径强烈依赖于电荷密度和互穿数。孔径和氯离子密度在决定膜的分离性能方面起着关键作用。互穿数较小且电荷密度较高的TFPM-Pa-X膜促进锂/镁分离。全电荷的2重互穿膜在打破锂通量（J）与锂对镁的选择性（S）之间的权衡方面具有优异性能。本研究可能有助于合理设计用于高性能离子分离的新型3D COF膜。
