Xu Shuting, Lin Haibo, Li Guiliang, Han Qiu, Wang Jianqiang, Liu Fu
Zhejiang International Joint Laboratory of Advanced Membrane Materials & Processes, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
Ningbo College of Materials Technology & Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
Adv Sci (Weinh). 2024 Dec;11(48):e2405539. doi: 10.1002/advs.202405539. Epub 2024 Oct 30.
Precise ions sieving at angstrom-scale is gaining tremendous attention thanks to its significant impact at the water-energy nexus. Herein, a novel polycation-modulated interfacial polymerization (IP) strategy is developed to prepare a heterogeneously charged covalent organic frameworks (COFs) membrane. Cationic poly(diallyldimethylammonium chloride) (PDDA) regulates the growth and assembly of anionic COFs nanosheets, which thus provides a negative, smooth top surface and positive, rough bottom surface, indicating the presence of heterogeneously charged angstrom-scale channels through the membrane. Experiments and simulations are conducted to understand the facilitated ions transport behavior relative to specific interactions raised by heterogeneously charged channels and angstrom-scale steric hinderance as well, rendering the membrane with robust mono-/divalent cations sieving capabilities. The selectivity (61.6) of Li to Mg in mixed saline under the continuous cross-flow filtration mode is superior to most of the reported nanofiltration membranes. This polycation-mediated interfacial polymerization strategy offers a compelling opportunity to develop versatile heterogeneously charged COF membranes for exquisite ion sieving.
由于其在水-能源关系方面的重大影响，埃级精确离子筛分正受到极大关注。在此，开发了一种新型的聚阳离子调节界面聚合（IP）策略来制备异质电荷共价有机框架（COF）膜。阳离子聚二烯丙基二甲基氯化铵（PDDA）调节阴离子COF纳米片的生长和组装，从而提供一个负电荷、光滑的顶面和正电荷、粗糙的底面，表明膜中存在异质电荷的埃级通道。进行了实验和模拟，以了解相对于异质电荷通道引起的特定相互作用以及埃级空间位阻而言的促进离子传输行为，使该膜具有强大的单/二价阳离子筛分能力。在连续错流过滤模式下，混合盐水中锂对镁的选择性（61.6）优于大多数已报道的纳滤膜。这种聚阳离子介导的界面聚合策略为开发用于精确离子筛分的通用异质电荷COF膜提供了一个极具吸引力的机会。
