Pressure-Driven Solvent Transport and Complex Ion Permeation through Graphene Oxide Membranes

Kai Wang, Irfani R. Ausri, Kyle A. Chu, Annela Seddon, Xiaowu (Shirley) Tang*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

1 Citation (Scopus)

Abstract

In this paper, an in-depth investigation of three graphene oxide (GO) based membranes—pure GO, Al 3+ intercalated GO (Al-GO), and poly(ethylene glycol) (PEG) modified GO (PEG-GO)—is presented. Both Al-GO and PEG-GO membranes have wider interlayer d-spacing compared to pure GO, and the d-spacing size correlates well to the cross-membrane water flux with J PEG-GO > J Al-GO > J GO . Pressure-driven transport of water/ethanol mixtures across all three types of GO membranes is dominated by solvent viscosity—not solvent polarity showing distinctively semi-hydrophilic membrane characteristics. Interestingly, the results suggest that both ethanol cluster size and molecular geometry contribute to preferential ethanol rejection, indicating that both GO and Al-GO membranes possess superior size sieving capability. Further, the lower permeation of tris(1,10-phenanthroline)ruthenium(II) (Ru(phen) 3 2+ ) compared to the charge-equivalent smaller-sized tris(bipyridine)ruthenium(II) (Ru(bpy) 3 2+ ) demonstrates the excellent steric selectivity of GO membranes. Compared to pure GO, the widened d-spacing in PEG-GO allows ≈100% higher ion permeation while ion flux through Al-GO is an order of magnitude lower, suggesting the significant role of electrostatic interaction in ion transport. In conclusion, these findings ought to enrich the understanding of the GO-based membranes and enable future rational designs for a wide range of applications, including water purification and solvent separation.

Original languageEnglish
Article number1802056
JournalAdvanced Materials Interfaces
Early online date30 Apr 2019
DOIs
Publication statusE-pub ahead of print - 30 Apr 2019

Keywords

  • ethanol rejection
  • graphene oxide membranes
  • pressure-driven transport
  • size-selective sieving

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