Lu Yahua, Zhou Rongkun, Wang Naixin, Yang Yuye, Zheng Zilong, Zhang Miao, An Quan-Fu, Yuan Jiayin
Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemical Engineering, Beijing University of Technology, Beijing, 100124, People's Republic of China.
Department of Materials and Environmental Chemistry, Stockholm University, 10691, Stockholm, Sweden.
Nanomicro Lett. 2023 Jun 7;15(1):147. doi: 10.1007/s40820-023-01101-w.
Two-dimensional (2D) membrane-based ion separation technology has been increasingly explored to address the problem of lithium resource shortage, yet it remains a sound challenge to design 2D membranes of high selectivity and permeability for ion separation applications. Zeolitic imidazolate framework functionalized modified layered double hydroxide (ZIF-8@MLDH) composite membranes with high lithium-ion (Li) permeability and excellent operational stability were obtained in this work by in situ depositing functional ZIF-8 nanoparticles into the nanopores acting as framework defects in MLDH membranes. The defect-rich framework amplified the permeability of Li, and the site-selective growth of ZIF-8 in the framework defects bettered its selectivity. Specifically speaking, the ZIF-8@MLDH membranes featured a high permeation rate of Li up to 1.73 mol m h and a desirable selectivity of Li/Mg up to 31.9. Simulations supported that the simultaneously enhanced selectivity and permeability of Li are attributed to changes in the type of mass transfer channels and the difference in the dehydration capacity of hydrated metal cations when they pass through nanochannels of ZIF-8. This study will inspire the ongoing research of high-performance 2D membranes through the engineering of defects.
二维（2D）膜基离子分离技术已被越来越多地探索以解决锂资源短缺问题，但设计用于离子分离应用的具有高选择性和渗透性的二维膜仍然是一项严峻挑战。在这项工作中，通过将功能性ZIF-8纳米颗粒原位沉积到作为层状双氢氧化物（MLDH）膜框架缺陷的纳米孔中，获得了具有高锂离子（Li）渗透性和优异操作稳定性的沸石咪唑酯骨架功能化改性层状双氢氧化物（ZIF-8@MLDH）复合膜。富含缺陷的框架提高了Li的渗透性，并且ZIF-8在框架缺陷中的位点选择性生长提高了其选择性。具体而言，ZIF-8@MLDH膜具有高达1.73 mol m⁻² h⁻¹的高Li渗透速率和高达31.9的理想Li/Mg选择性。模拟结果表明，Li选择性和渗透性的同时提高归因于传质通道类型的变化以及水合金属阳离子通过ZIF-8纳米通道时脱水能力的差异。这项研究将通过缺陷工程激发正在进行的高性能二维膜研究。
