浙江大学张庆华研究小组研制了，用于高分辨率Li⁺/Mg²⁺分离的脱水增强离子识别的三嗪共价有机框架材料。2025年1月21日出版的《德国应用化学》发表了这项成果。

研究人员报道了一种对Li⁺/Mg²⁺具有高分辨率的三嗪共价有机框架（COF）膜，它可以快速传输Li⁺，同时几乎完全抑制Mg²⁺的渗透。COF膜对Mg²⁺的高截除率是通过施加离子脱水和构建能量阱实现的。COF通道适宜的亲水性环境促进了Li⁺与带负电官能团的解离，使得Li⁺在磺酸侧链的支持下进行跳迁，缩短了Li⁺的扩散路径。

在高盐度电渗析条件下，COF膜表现出良好的Li⁺/Mg²⁺分离性能（收集的溶液中未检测到Mg²⁺），实现了高效的锂回收和高产品纯度（Li₂CO₃: 99.3%）。该膜设计策略使电渗析锂提取过程中具有高能效和强大的锂提取功能，并可推广到其他与能源和分离相关的膜。

研究人员表示，从盐湖盐水中精确、快速地提取锂对于满足全球对锂资源的需求至关重要。然而，如何设计出对目标离子具有准确识别，和快速传输路径的离子传输膜仍然是一个重要挑战。

附：英文原文

Title: Dehydration-enhanced Ion Recognition of Triazine Covalent Organic Frameworks for High-resolution Li+/Mg2+ Separation

Author: Qinghua Zhang, Wentong Meng, Sifan Chen, Ming Wu, Feng Gao, Yang Hou, Xiaoli Zhan, Wei Hu, Lijun Liang

Issue&Volume: 2025-01-21

Abstract: The precise and rapid extraction of lithium from salt-lake brines is critical to meeting the global demand for lithium resources. However, it remains a major challenge to design ion-transport membranes with accurate recognition and fast transport path for the target ion. Here, we report a triazine covalent organic framework (COF) membrane with high resolution for Li+ and Mg2+ that enables fast Li+ transport while almost completely inhibiting Mg2+ permeation. The remarkably high rejection of Mg2+ by the COF membrane is achieved via imposed ion dehydration and the construction of the energy well. The proper hydrophilic environment of the COF channel promotes the dissociation of Li+ from the negatively charged functional groups, allowing Li+ for hopping transport supported by the sulfonate side-chains to shorten the diffusion path of Li+. Under high-salinity electrodialysis conditions, the COF membrane demonstrates robust Li+/Mg2+ separation performance (No Mg2+ were detected in the collected solution), achieving efficient lithium recovery and high product purity (Li2CO3: 99.3%). This membrane design strategy enables high energy efficiency and powerful lithium extraction in the electrodialysis lithium extraction process, and can be generalized to other energy and separation related membranes.

DOI: 10.1002/anie.202422423

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202422423