Gas and liquid permeation properties of modified interfacial composite reverse osmosis membranes

Jennifer S. Louie, Ingo Pinnau, Martin Reinhard*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


Gas permeation tests using nitrogen, oxygen, hydrogen, helium and carbon dioxide were performed to assess how membrane modification procedures affect the separating layer morphology of thin-film composite reverse osmosis membranes. Gas selectivity data provided evidence for the presence of nanoscale separating layer defects in dry samples of six commercial membrane types. These defects were eliminated when the membrane surface was coated with a polyether-polyamide block copolymer (PEBAX 1657), as indicated by a 25-fold decrease in gas permeance and at least a 2-fold increase in most selectivity values. Treatment with n-butanol followed by drying reduced water flux and gas flux by 30% and 75%, respectively, suggesting that using n-butanol as a solvent for applying coatings negatively affects membrane performance. The results of this study demonstrate that gas permeation measurements can be used to detect morphological features that impact gas and water membrane flux.

Original languageEnglish (US)
Pages (from-to)793-800
Number of pages8
JournalJournal of Membrane Science
Issue number2
StatePublished - Dec 1 2008
Externally publishedYes


  • Aromatic polyamide
  • Coating
  • Gas permeation
  • Polyether-polyamide block copolymer
  • RO membranes

ASJC Scopus subject areas

  • Biochemistry
  • General Materials Science
  • Physical and Theoretical Chemistry
  • Filtration and Separation


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