中科大徐铜文院士等：氧化石墨烯膜中刚性限域相互作用重构水合层实现高效阴离子分离

对亚纳米环境下阴离子传输行为的理解可以指导高性能阴离子分离膜的设计。

近日，中国科学技术大学徐铜文院士、左培培副研究员、合肥工业大学冉瑾教授和付岑峰副教授等人在Science China Materials发表论文，利用荷电交联剂桥接氧化石墨烯纳米片构建了荷电化限域的二维离子传输通道。

本文要点

1. 该通道对阴离子施加的刚性限域相互作用可以补偿离子进入通道时脱水所需的能垒，同时使得不同阴离子的水合层内的水分子发生了不同程度的重排行为。
2. 在阴离子水合层构型演化过程中，水合层内的水分子在发生旋转同时，其与离子中心的距离也发生改变。
3. 由于不同离子的构型演化差异较大，荷电化限域的膜实现了高效的一/二价阴离子的分离，对Cl⁻/SO₄²⁻的选择性达到了125，优于目前报道的其他阴离子分离膜。

理解离子水合层在脱水过程中的构型演化将是设计新一代高性能阴离子分离膜的关键。

Figure 1. Schematic illustration of original GO channels and rigidly confined GO channels. (a) Simply stacking the GO nanosheets as orderly laminated membranes. The nanosheets swell in aqueous solution, thus creating non-selective channels and simultaneously damaging the mechanical stability of membranes. (b) Covalently bridging the nanosheets with uncharged linkers to form the rigidly confined 2D channels. These channels rely solely on size effects to realize anion selectivity improved a little, but obviously sacrifice anion permeability. (c) Covalently bridging the nanosheets with charged linkers to form 2D channels combining physical rigidity and chemical affinity to anions. These channels impose a rigidly confined interaction between the channels and the anions. This can significantly increase both anion permeability and selectivity. Optimized configurations of the interlayer channel of (d) BZ@GO and (e) APV@GO membranes by density functional theory calculations. (f) Digital photo of the free-standing APV@GO membrane.

作者简介

Tongwen Xu (徐铜文) is a chair professor at the University of Science and Technology of China. He received his Bachelor’s degree in 1989 and his Master’s degree in 1992 from Hefei University of Technology, China. He received his PhD degree in chemical engineering in 1995 from Tianjin University, China and completed postdoctoral research in polymer science at Nankai University, China. He was a visiting scientist at the University of Tokyo, Tokyo Institute of Technology and Gwangju Institute of Science and Technology. His research interests cover polymers, membranes and related processes.

Jin Ran (冉瑾) is a professor at Hefei University of Technology. She graduated with a Bachelor’s degree from Hefei University of Technology in 2009 and obtained her PhD degree in 2015 under the supervision of Professor Tongwen Xu at the University of Science and Technology of China. Her research interests mainly focus on the development of membrane materials for applications in water electrolysis for hydrogen production, wastewater treatment, and lithium extraction from salt lakes.

文章信息

Rui Jia, Zheng Ji, Xingyun Li, Qinshan Zhu, Jiu Yang, Ruonan Tan, Zongliang Wan, Jingjing Gu, Ziqiang Hong, Cen-Feng Fu, Jin Ran, Suixin Zhang, Peipei Zuo, Tongwen Xu. Reconfiguring hydration shells by rigidly confined interaction within graphene oxide membranes for ultra-efficient anion separation. Sci. China Mater. (2025).

https://doi.org/10.1007/s40843-025-3538-6