Controllable ion transport and precise ion sieving are crucial for sustainable water treatment and resource recovery. 2D materials, including graphene oxide (GO) with tunable nanochannels, are emerging as ideal material platforms to develop ion sieving membranes. However, accurate ion sieving remains challenging due to the swollen and enlarged interlayer spacing of GO membranes in aqueous solution, resulting in the non-selective of small ions. Here, we reformed the GO nanosheets by physical reduction method and modified them with negatively charged molecule chains. The nanochannel sizes and electronegativity of the stacked 2D membranes were precisely controlled simultaneously. As a result, 2D nanochannel membrane with fast permeability, high efficiency and accurate Cl−/SO42− separation was constructed. The characterization and performance analysis further proved that the interlayer spacing and electrification of 2D nanochannels are strongly related to ion sieving. By precisely adjusting the synergy between the two, Cl−/SO42− selectivity up to 91.83 with Cl− permeation rate of 1.03 mol m−2h−1 was achieved, which is superior to state-of-the-art ion sieving membranes. Our study provides new insights into understanding ion separation mechanisms within nanochannels and enables the development for the precise construction of nanochannels to manipulate the selective transport of ions.

中文翻译：

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纳米限域静电相互作用，用于氧化石墨烯膜中的高效阴离子筛分


可控的离子传输和精确的离子筛分对于可持续的水处理和资源回收至关重要。二维材料，包括具有可调谐纳米通道的氧化石墨烯 （GO），正在成为开发离子筛分膜的理想材料平台。然而，由于 GO 膜在水溶液中的层间距膨胀和扩大，导致小离子无选择性，因此准确的离子筛分仍然具有挑战性。在这里，我们通过物理还原法对 GO 纳米片进行了整改，并用带负电荷的分子链对其进行修饰。堆叠 2D 膜的纳米通道大小和电负性同时得到精确控制。结果，构建了具有快速渗透性、高效率和准确 Cl-/SO42-分离的 2D 纳米通道膜。表征和性能分析进一步证明，二维纳米通道的层间距和带电与离子筛分密切相关。通过精确调节两者之间的协同作用，在 1.03 mol m-2h-1 的 Cl-渗透率下，实现了高达 91.83 的 Cl-/SO42-选择性，优于最先进的离子筛膜。我们的研究为理解纳米通道内的离子分离机制提供了新的见解，并为精确构建纳米通道以操纵离子的选择性传输提供了新的见解。