State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, College of Chemical Engineering, Nanjing Tech University, 5 Xinmofan Road, 210009, Nanjing, P.R. China.
Nat Commun. 2019 Mar 19;10(1):1253. doi: 10.1038/s41467-019-09286-8.
Ion transport is crucial for biological systems and membrane-based technology. Atomic-thick two-dimensional materials, especially graphene oxide (GO), have emerged as ideal building blocks for developing synthetic membranes for ion transport. However, the exclusion of small ions in a pressured filtration process remains a challenge for GO membranes. Here we report manipulation of membrane surface charge to control ion transport through GO membranes. The highly charged GO membrane surface repels high-valent co-ions owing to its high interaction energy barrier while concomitantly restraining permeation of electrostatically attracted low-valent counter-ions based on balancing overall solution charge. The deliberately regulated surface-charged GO membranes demonstrate remarkable enhancement of ion rejection with intrinsically high water permeance that exceeds the performance limits of state-of-the-art nanofiltration membranes. This facile and scalable surface charge control approach opens opportunities in selective ion transport for the fields of water transport, biomimetic ion channels and biosensors, ion batteries and energy conversions.
离子传输对于生物系统和基于膜的技术至关重要。原子级薄的二维材料，特别是氧化石墨烯（GO），已成为开发用于离子传输的合成膜的理想构建块。然而，在加压过滤过程中排除小离子仍然是 GO 膜面临的挑战。在这里，我们报告了通过操纵膜表面电荷来控制 GO 膜中的离子传输。由于高相互作用能垒，带高电荷的 GO 膜表面排斥高价共离子，同时根据整体溶液电荷平衡来限制静电吸引的低价抗衡离子的渗透。经过精心调控表面电荷的 GO 膜表现出卓越的离子排斥性能，同时具有内在的高通量水渗透性，超过了最先进的纳滤膜的性能极限。这种简单且可扩展的表面电荷控制方法为水传输、仿生离子通道和生物传感器、离子电池和能量转换等领域的选择性离子传输开辟了机会。
