Physico-chemical characterization of NF/RO membrane active layers by Rutherford backscattering spectrometry

Baoxia Mi, Orlando Coronell, Benito J. Mariñas, Fumiya Watanabe, David G. Cahill, Ivan Petrov

Research output: Contribution to journalArticlepeer-review


The physico-chemical properties of the active layer of nanofiltration/reverse osmosis (NF/RO) membranes were characterized by Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). NF/RO membranes with active layer materials including polyamide (PA), polyvinyl alcohol derivative (PVA), PA-PVA, and sulfonated-polyethersulfone (SPES) were investigated. SEM and TEM images of membrane cross-sections confirmed the presence of a denser active layer supported by an asymmetric porous polysulfone structure but could only provide a rough estimate of membrane active layer average thickness. RBS provided an accurate tool to determine the elemental composition of NF/RO membrane active and support layers, and the thickness and roughness of the membrane active layer. The oxygen-to-nitrogen molecular ratio obtained for PA membranes was in the range of 1.1-3.0, which is consistent with the reported presence of unreacted carboxyl groups in the active layer surface of this type of membranes.

Original languageEnglish (US)
Pages (from-to)71-81
Number of pages11
JournalJournal of Membrane Science
Issue number1-2
StatePublished - Oct 5 2006


  • Membrane active layer thickness
  • Membrane elemental composition
  • Nanofiltration
  • RBS
  • Reverse osmosis
  • Roughness
  • Rutherford backscattering spectrometry

ASJC Scopus subject areas

  • Filtration and Separation
  • Polymers and Plastics


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