Positively charged membranes with fine-tuned nanopores for ultrafast and high-precision cation separation

Min Gyu Shin, Jin Young Seo, Hosik Park, You In Park, Seulgi Ji, Sun Sook Lee, Jung Hyun Lee

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


There is significant interest in high-performance positively charged membranes that enable the fast and high-precision separation of various cationic substances for purifying water and recovering precious metals. This study demonstrates that the ultrafast and precise separation of cations can be achieved using positively charged membranes with fine-controlled nanopores fabricatedviaa solvent-controlled swelling-diffusion (SD) method. Polyamide (PA) membranes are treated with a dimethyl sulfoxide/water mixture solvent containing a rationally designed, positively charged strong polyelectrolyte, followed by water washing. Solvent-induced PA activation and polyelectrolyte incorporation into PA cooperatively produce a highly-permeable and more uniform PA nanopore structure with a strong and stable positive surface charge. Consequently, the SD-modified membrane exhibits unprecedentedly high water permeance (∼22 L m−2h−1bar−1) and high rejection (∼99.5% for MgCl2, >90% for hazardous metals) and selectivity (∼23.4 for Li+/Mg2+) for divalent cations, significantly outperforming commercial and previously reported membranes. Our proposed strategy provides a commercially viable means for the fabrication of high-performance functional membranes and coatings and sheds light on their structure-performance relationship.

Original languageEnglish
Pages (from-to)24355-24364
Number of pages10
JournalJournal of Materials Chemistry A
Issue number43
Publication statusPublished - 2021 Nov 21

Bibliographical note

Funding Information:
This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (2019R1A2C1002333), Ministry of Science and ICT (SI2111-40) and the Technology Innovation Program (20010914) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea).

Publisher Copyright:
© The Royal Society of Chemistry 2021.

ASJC Scopus subject areas

  • General Chemistry
  • Renewable Energy, Sustainability and the Environment
  • General Materials Science


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