Robust Covalently Cross-linked Polybenzimidazole/Graphene Oxide Membranes for High-Flux Organic Solvent Nanofiltration

Fan Fei, Levente Cseri, Gyorgy Szekely*, Christopher F. Blanford

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

75 Scopus citations

Abstract

Robust, readily scalable, high-flux graphene oxide (GO) mixed matrix composite membranes were developed for organic solvent nanofiltration. Hydroxylated polybenzimidazole was synthesized by N-benzylation of polybenzimidazole with 4-(chloromethyl)benzyl alcohol, which was confirmed by FTIR and NMR spectroscopy. Flat-sheet composite membranes comprising of polybenzimidazoles and 1 or 2 wt % GO were fabricated via conventional blade coating and phase inversion. Subsequently, GO was covalently anchored to the hydroxyl groups of the polymer using a diisocyanate cross-linking agent. The even distribution of GO in the membranes was mapped by visible-light microscopy. Hydroxylation and incorporation of GO in the polymer matrix increased the permeance up to 45.2 ± 1.6 L m-2 h-1 bar-1 in acetone, nearly 5 times higher than the unmodified benchmark membrane. The enhancement in permeance from the addition of GO did not compromise the solute rejection. The composite membranes were found to be tight in seven organic solvents, having molecular weight cut-offs (MWCO) as low as 140 g mol-1. Permeance increased with increasing solvent polarity, while rejection of a 420 g mol-1 pharmaceutical remained over 93%. The covalent anchoring resulted in robust composite membranes that maintained constant performance over 14 days in a continuous cross-flow configuration.

Original languageEnglish (US)
Pages (from-to)16140-16147
Number of pages8
JournalACS Applied Materials and Interfaces
Volume10
Issue number18
DOIs
StatePublished - May 9 2018

Keywords

  • composite membrane
  • cross-linking
  • graphene sieve
  • mixed matrix membrane
  • surface modification

ASJC Scopus subject areas

  • Materials Science(all)

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