膜
石墨烯
渗透
分子动力学
化学物理
氢键
化学工程
材料科学
氧化物
渗透
离子
化学
分子
计算化学
纳米技术
有机化学
生物化学
工程类
作者
Hai-Guang Zhang,Xie Quan,Lei Du,Gaoliang Wei,Shuo Chen,Hongtao Yu,Yingchao Dong
标识
DOI:10.1073/pnas.2219098120
摘要
Graphene oxide (GO) membranes with nanoconfined interlayer channels theoretically enable anomalous nanofluid transport for ultrahigh filtration performance. However, it is still a significant challenge for current GO laminar membranes to achieve ultrafast water permeation and high ion rejection simultaneously, because of the contradictory effect that exists between the water–membrane hydrogen-bond interaction and the ion–membrane electrostatic interaction. Here, we report a vertically aligned reduced GO (VARGO) membrane and propose an electropolarization strategy for regulating the interfacial hydrogen-bond and electrostatic interactions to concurrently enhance water permeation and ion rejection. The membrane with an electro-assistance of 2.5 V exhibited an ultrahigh water permeance of 684.9 L m −2 h −1 bar −1 , which is 1–2 orders of magnitude higher than those of reported GO-based laminar membranes. Meanwhile, the rejection rate of the membrane for NaCl was as high as 88.7%, outperforming most reported graphene-based membranes (typically 10 to 50%). Molecular dynamics simulations and density-function theory calculations revealed that the electropolarized VARGO nanochannels induced the well-ordered arrangement of nanoconfined water molecules, increasing the water transport efficiency, and thereby resulting in improved water permeation. Moreover, the electropolarization effect enhanced the surface electron density of the VARGO nanochannels and reinforced the interfacial attractive interactions between the cations in water and the oxygen groups and π-electrons on the VARGO surface, strengthening the ion-partitioning and Donnan effect for the electrostatic exclusion of ions. This finding offers an electroregulation strategy for membranes to achieve both high water permeability and high ion rejection performance.
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