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Rejection of small and uncharged chemicals of emerging concern by reverse osmosis membranes: The role of free volume space within the active skin layer

Journal Article


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Abstract


  • Free-volume hole-radii of the active skin layer of one seawater and two low pressure reverse osmosis

    (RO) membranes – namely SWC5, ESPAB, and ESPA2 respectively – were evaluated using positron annihilation

    lifetime spectroscopy (PALS) with a slow positron beam. The results were related to the rejection

    of boric acid and eight N-nitrosamines to provide insights to the transport of these small solutes through

    RO membranes. At pH 8 (which is the experimental pH in this study), these solutes are uncharged. PALS

    analysis showed that the SWC5 has the smallest mean free-volume hole-radius (0.259 nm) among the

    three RO membranes investigated here. Correspondingly, the SWC5 membrane exhibited the highest

    rejection of boric acid and all N-nitrosamines. Results reported here also showed that the rejection of

    these chemicals increased in the order of increasing molecular volume. In addition, the difference in their

    rejection amongst the three RO membranes investigated here was most apparent for those (i.e., boric acid

    and N-nitrosodimethylamine (NDMA)) with a small molecular volume. The EPSA2 and ESPAB were determined

    to have mean free-volume hole-radius of 0.289 nm. However, the ESPAB membrane had lower

    water permeability and showed considerably higher rejection of boric acid and NDMA than the ESPA2

    membrane. These results suggest that in addition to the mean free-volume hole-radius, other membrane

    parameters and properties such as the free-volume hole-radius distribution and thickness of the active

    skin layer can also play a role in governing the rejection of small and uncharged solutes by RO

    membranes.

Authors


  •   Fujioka, Takahiro (external author)
  •   Oshima, Nagayasu (external author)
  •   Suzuki, Ryoichi (external author)
  •   Khan, Stuart J. (external author)
  •   Roux, Annalie (external author)
  •   Poussade, Yvan (external author)
  •   Drewes, Jörg E. (external author)
  •   Nghiem, Long D.

Publication Date


  • 2013

Citation


  • Fujioka, T., Oshima, N., Suzuki, R., Khan, S. J., Roux, A., Poussade, Y., Drewes, J. E. & Nghiem, L. D. (2013). Rejection of small and uncharged chemicals of emerging concern by reverse osmosis membranes: The role of free volume space within the active skin layer. Separation and Purification Technology, 116 426-432.

Scopus Eid


  • 2-s2.0-84880078251

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2144&context=eispapers

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/1135

Has Global Citation Frequency


Number Of Pages


  • 6

Start Page


  • 426

End Page


  • 432

Volume


  • 116

Place Of Publication


  • United Kingdom

Abstract


  • Free-volume hole-radii of the active skin layer of one seawater and two low pressure reverse osmosis

    (RO) membranes – namely SWC5, ESPAB, and ESPA2 respectively – were evaluated using positron annihilation

    lifetime spectroscopy (PALS) with a slow positron beam. The results were related to the rejection

    of boric acid and eight N-nitrosamines to provide insights to the transport of these small solutes through

    RO membranes. At pH 8 (which is the experimental pH in this study), these solutes are uncharged. PALS

    analysis showed that the SWC5 has the smallest mean free-volume hole-radius (0.259 nm) among the

    three RO membranes investigated here. Correspondingly, the SWC5 membrane exhibited the highest

    rejection of boric acid and all N-nitrosamines. Results reported here also showed that the rejection of

    these chemicals increased in the order of increasing molecular volume. In addition, the difference in their

    rejection amongst the three RO membranes investigated here was most apparent for those (i.e., boric acid

    and N-nitrosodimethylamine (NDMA)) with a small molecular volume. The EPSA2 and ESPAB were determined

    to have mean free-volume hole-radius of 0.289 nm. However, the ESPAB membrane had lower

    water permeability and showed considerably higher rejection of boric acid and NDMA than the ESPA2

    membrane. These results suggest that in addition to the mean free-volume hole-radius, other membrane

    parameters and properties such as the free-volume hole-radius distribution and thickness of the active

    skin layer can also play a role in governing the rejection of small and uncharged solutes by RO

    membranes.

Authors


  •   Fujioka, Takahiro (external author)
  •   Oshima, Nagayasu (external author)
  •   Suzuki, Ryoichi (external author)
  •   Khan, Stuart J. (external author)
  •   Roux, Annalie (external author)
  •   Poussade, Yvan (external author)
  •   Drewes, Jörg E. (external author)
  •   Nghiem, Long D.

Publication Date


  • 2013

Citation


  • Fujioka, T., Oshima, N., Suzuki, R., Khan, S. J., Roux, A., Poussade, Y., Drewes, J. E. & Nghiem, L. D. (2013). Rejection of small and uncharged chemicals of emerging concern by reverse osmosis membranes: The role of free volume space within the active skin layer. Separation and Purification Technology, 116 426-432.

Scopus Eid


  • 2-s2.0-84880078251

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2144&context=eispapers

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/1135

Has Global Citation Frequency


Number Of Pages


  • 6

Start Page


  • 426

End Page


  • 432

Volume


  • 116

Place Of Publication


  • United Kingdom