Freestanding two-dimensional nanofluidic membranes modulated by zwitterionic polyelectrolyte for mono-/di-valent ions selectivity transport

Liheng Dai, Sichen Pang, Shiyi Li, Zhiyuan Yi, Kai Qu, Yixing Wang, Yulin Wu, Siyao Li, Linfeng Lei, Kang Huang, Xuhong Guo, Zhi Xu

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Effective separation of mono-/di-valent metal ions based on membrane technology is highly desirable in the energy storage and environmental protection field, but requires membranes capable of selective recognition of ions with similar nano-scale size. In this work, we designed and synthesized the sulfonate polyethylenimine (PEI-SO3H), as a zwitterionic polyelectrolyte, and integrated it into two-dimensional (2D) graphene oxide (GO) confined channels. Stable and sub-nanometer ion-selective transport channels enable fast transport of monovalent metal ions with high mono-/di-valent ion selectivity for K+/Mg2+ (12.2), Na+/Mg2+ (11.4) and Li+/Mg2+ (10.1) under electric field. Notably, the hydration compensation-promoting diffusion (HCPD) mechanism based on the synergistic effect of amino groups as compensation sites and sulfonic acid groups as recognition sites was proposed to understand the high-efficiency ion-selective transport process. In addition, instructed by abovementioned theory, the 2D vermiculite membrane was also designed to well realize the mono-/di-valent ions separation. This study provides a new strategy to construct freestanding 2D membranes with efficient ion-selective transport channels instructed by HCPD theory, which is expected to expand the potential for using membranes in the lithium extraction.

Original languageEnglish
Article number121621
JournalJournal of Membrane Science
Volume677
DOIs
StatePublished - 5 Jul 2023

Keywords

  • Confined mass transfer
  • Graphene oxide
  • Ion-selective transport
  • Monovalent/divalent ions separation
  • Two-dimensional membrane

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