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Title: Interaction-based ion selectivity exhibited by self-assembled, cross-linked zwitterionic copolymer membranes
Water filtration membranes with advanced ion selectivity are urgently needed for resource recovery and the production of clean drinking water. This work investigates the separation capabilities of cross-linked zwitterionic copolymer membranes, a self-assembled membrane system featuring subnanometer zwitterionic nanochannels. We demonstrate that selective zwitterion–anion interactions simultaneously control salt partitioning and diffusivity, with the permeabilities of NaClO 4 , NaI, NaBr, NaCl, NaF, and Na 2 SO 4 spanning roughly three orders of magnitude over a wide range of feed concentrations. We model salt flux using a one-dimensional transport model based on the Maxwell–Stefan equations and show that diffusion is the dominant mode of transport for 1:1 sodium salts. Differences in zwitterion–Cl − and zwitterion–F − interactions granted these membranes with the ultrahigh Cl − /F − permselectivity ( P Cl- /P F- = 24), enabling high fluoride retention and high chloride passage even from saline mixtures of NaCl and NaF.  more » « less
Award ID(s):
1553661 1843847
PAR ID:
10294064
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Proceedings of the National Academy of Sciences
Volume:
118
Issue:
37
ISSN:
0027-8424
Page Range / eLocation ID:
e2022198118
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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