Abstract:

With the development of lithium batteries, aerospace and other industries, there is an urgent need to develop lithium resources efficiently. Membrane technology with the advantages of low energy consumption and simple operation is widely used in Mg-Li separation. Metal-organic frameworks (MOFs) have such characteristics as rich topology, large specific surface area and stable porosity, and thus they can be used to develop ideal membrane materials for Mg-Li separation. This paper highlighted an overview of the main types and preparation strategies of MOFs-based membranes, focused on comparing Mg-Li selectivity of MOFs polycrystalline membranes, MOFs polyamide membranes and MOFs channel membranes, and analyzed the key mechanisms behind Mg-Li selectivity (involving size sieving effects, ion-group interactions, dehydration-rehydration mechanisms and Donnan theory). Moreover, MOFs-based membranes improvement for Mg-Li separation was prospected, including MOFs selection and modification, optimization of substrate preparation methods and substrate modification. Finally, it’s expected to further improve the selectivity of Mg-Li and the stability of MOFs-based membranes, and provide new ideas for application promotion.

Key words: metal-organic frameworks, membrane materials, Mg-Li separation, separation selectivity

摘要：

随着锂电池、航空航天等工业的迅速发展，锂资源的高效开发利用尤为关键。膜分离技术因能耗低、操作简便等优势，被广泛应用于镁锂分离领域。金属有机框架（MOFs）具有丰富的拓扑结构、较大的比表面积及稳定的孔隙率等特性，可用于开发适于镁锂分离的理想膜材料。本文着重概述了MOFs基膜的主要类型及制备策略，重点比较了MOFs多晶膜、MOFs聚酰胺膜及MOFs通道膜三类MOFs基膜的镁锂分离选择性，并分析了其关键机制（主要包括尺寸筛分效应、离子-基团相互作用、脱水-再水合机制与Donnan理论）。进一步展望了面向镁锂分离的MOFs基膜的改良方向，主要分为MOFs选择与改性、基膜制备方法优化以及基底改性，有望进一步提升镁锂分离选择性以及MOFs基膜稳定性，为其应用推广提供新的研发思路。

关键词: 金属有机框架, 膜材料, 镁锂分离, 分离选择性