Novel Inorganic Integrated Membrane Electrodes for Membrane Capacitive Deionization

Qinghao Wu, Dawei Liang, Shanfu Lu, Jin Zhang, Haining Wang, Yan Xiang, Doron Aurbach

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

In capacitive deionization (CDI), coion repulsion and Faradaic reactions during charging reduce the charge efficiency (CE), thus limiting the salt adsorption capacity (SAC) and energy efficiency. To overcome these issues, membrane CDI (MCDI) based on the enhanced permselectivity of the anode and cathode is proposed using the ion-exchange polymer as the independent membrane or coating. To develop a novel and cost-effective MCDI system, we fabricated an integrated membrane electrode using a thin layer of the inorganic ion-exchange material coated on the activated carbon (AC) electrode, which effectively improves the ion selectivity. Montmorillonite (MT, Al2O9Si3) and hydrotalcite (HT, Mg6Al2(CO3)(OH)16·4H2O) were selected as the main active anion- and cation-exchange materials, respectively, for the cathode and anode. The HT-MT MCDI system employing HT-AC and MT-AC electrodes obtained a CE of 90.5% and an SAC of 15.8 mg g-1after 100 consecutive cycles (50 h); these values were considerably higher than those of the traditional CDI system employing pristine AC electrodes (initially, a CE of 55% and an SAC of 10.2 mg g-1, which attenuated continuously to zero, and even “inverted work” occurs after 50 h, i.e., desorption during charging and adsorption during discharging). The HT-MT MCDI system showed moderate tolerance to organic matters during desalination and retained 84% SAC and 89% CE after 70 cycles in 50-200 mg L-1sodium alginate. This study demonstrates a simple and cost-effective method for fabricating high-CE electrodes for desalination with great application potential.

Original languageEnglish
Pages (from-to)46537-46548
Number of pages12
JournalACS applied materials & interfaces
Volume13
Issue number39
DOIs
StatePublished - 6 Oct 2021

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society

Keywords

  • capacitive deionization
  • hydrotalcite
  • integrated membrane electrode
  • montmorillonite
  • permselectivity

Fingerprint

Dive into the research topics of 'Novel Inorganic Integrated Membrane Electrodes for Membrane Capacitive Deionization'. Together they form a unique fingerprint.

Cite this