Simultaneous, monovalent ion selectivity with polyelectrolyte multilayers and intercalation electrodes in capacitive deionization

K. Singh, S. Sahin, J.G. Gamaethiralalage, Rafael L. Zornitta, L.C.P.M. de Smet*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

15 Citations (Scopus)

Abstract

Selective ion separation via capacitive deionization (CDI) is of relevance because of its environmental and industrial applications in water purification and softening, heavy metal removal, and resource recovery. Conventionally, carbon electrodes and ion-selective membranes have been used for selective removal of anions and cations. In this study, we engineered a CDI cell with two identical NiHCF electrodes, separated by an anion–exchange membrane coated with a polyelectrolyte multilayer (PEM), for simultaneous and selective separation of monovalent over divalent anions and cations. The modified membrane rejects divalent over monovalent anions while the NiHCF electrodes selectively adsorb monovalent over divalent ions. A separation factor (β) of 7 < β < 14 was obtained for Cl over SO42−, while an average β of ≈ 17 was obtained for Na+ over Mg2+, reflecting the preference of the modified membrane and the electrodes, respectively. Moreover, this preference was preserved at low concentrations of monovalent ions as well. This tandem use of intercalation electrodes and a PEM membrane provides a new and facile method for simultaneous cation and anion selectivity in CDI, opening new avenues for enhanced and tunable separations from complex ion mixtures

Original languageEnglish
Article number128329
JournalChemical Engineering Journal
Volume432
DOIs
Publication statusPublished - 15 Mar 2022

Keywords

  • Capacitive deionization
  • Ion selectivity
  • Polyelectrolyte multilayers
  • Prussian blue analogues

Fingerprint

Dive into the research topics of 'Simultaneous, monovalent ion selectivity with polyelectrolyte multilayers and intercalation electrodes in capacitive deionization'. Together they form a unique fingerprint.

Cite this