1. Microporous membrane with ionized sub-nanochannels enabling highly selective monovalent and divalent anion separation
- Author
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Mei-Ling Liu, Yu Chen, Chuan Hu, Chun-Xu Zhang, Zheng-Jun Fu, Zhijun Xu, Young Moo Lee, and Shi-Peng Sun
- Subjects
Science - Abstract
Abstract Membranes tailored for selective ion transport represent a promising avenue toward enhancing sustainability across various fields including water treatment, resource recovery, and energy conversion and storage. While nanochannels formed by polymers of intrinsic microporosity (PIM) offer a compelling solution with their uniform and durable nanometer-sized pores, their effectiveness is hindered by limited interactions between ions and nanochannel. Herein, we introduce the randomly twisted V-shaped structure of Tröger’s Base unit and quaternary ammonium groups to construct ionized sub-nanochannel with a window size of 5.89–6.54 Å between anion hydration and Stokes diameter, which enhanced the dehydrated monovalent ion transport. Combining the size sieving and electrostatic interaction effects, sub-nanochannel membranes achieved exceptional ion selectivity of 106 for Cl-/CO3 2- and 82 for Cl-/SO4 2-, significantly surpassing the state-of-the-art membranes. This work provides an efficient template for creating functionalized sub-nanometer channels in PIM membranes, and paves the way for the development of precise ion separation applications.
- Published
- 2024
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