Designing and synthesizing membranes with fast and selective cation transport remains extremely challenging. Herein, ZGO membranes are conceived via a two-dimensional zeolitic imidazolate framework (ZIF-L) grown on graphene oxide (GO), with ZIF-L as an interlayer that increases both vertical interlayer spacing and lateral tortuous path spacing of GO, thus improving the stability, selectivity, and ion permeation of the ZGO lamellar membrane. Structural analyses reveal that GO surfaces with abundant oxygen functional groups favored the formation of ZIF-L with 316 crystal planes and offered a high ion-accessible surface area. More importantly, the ZGO membrane delivers an excellent K permeability of 86.9 mmol m h and K/Mg selectivity up to 266, outperforming state-of-the-art GO-based membranes. Furthermore, molecular simulations confirm that the hydrogen bonding between hydrated cations and polar functional groups of ZGO membranes substantially restricted the dynamical transport of bivalent cation, and thus led to excellent cation selectivity. These results open a pathway to developing membranes for fast and highly selective ion separations in the future.

中文翻译：

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在氧化石墨烯夹层中生长 ZIF-L 种子以合成高效的阳离子筛膜

设计和合成具有快速和选择性阳离子传输的膜仍然极具挑战性。在此，ZGO膜是通过在氧化石墨烯（GO）上生长的二维沸石咪唑酯骨架（ZIF-L）构想的，ZIF-L作为中间层，增加了GO的垂直层间间距和横向曲折路径间距，从而改善ZGO层状膜的稳定性、选择性和离子渗透性。结构分析表明，具有丰富氧官能团的 GO 表面有利于形成具有 316 个晶面的 ZIF-L，并提供高离子可及表面积。更重要的是，ZGO 膜具有 86.9 mmol m h 的优异 K 渗透率和高达 266 的 K/Mg 选择性，优于最先进的 GO 基膜。此外，分子模拟证实，ZGO膜的水合阳离子和极性官能团之间的氢键显着限制了二价阳离子的动态传输，从而具有优异的阳离子选择性。这些结果为未来开发用于快速和高选择性离子分离的膜开辟了道路。