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Characterising humic acid fouling of nanofiltration membranes using bisphenol A as a molecular indicator

Journal Article


Abstract


  • Fouling of nanofiltration (NF) membranes by humic acids was investigated using bisphenol

    A (BPA) as an indicator chemical to differentiate between various mechanisms that may

    lead to a change in solute rejection. Three commercially available NF membranes were

    investigated and an accelerated fouling condition was achieved with a foulant mixture

    containing humic acids in an electrolyte matrix. The effects of membrane fouling on the

    rejection of BPA were interpreted with respect to the membrane pore sizes and the fouling

    characteristics. Results reported here indicate that calcium concentration in the feed solution

    could be a major factor governing the humic acid fouling process. Moreover, a critical

    concentration of calcium in the feed solution was observed, at which membrane fouling

    was most severe. Membrane fouling characteristics were observed by their influence on

    BPA rejection. Such influence could result in either an increase or decrease in rejection

    of BPA by the three different membranes depending on the rejection mechanisms involved.

    It is hypothesized that these mechanisms could occur simultaneously and that the effects

    of each might not be easily distinguished. However, it was observed that their relative contribution

    was largely dependent upon membrane pore size. Pore blocking, which resulted

    in a considerable improvement in rejection, was prominent for the more open pore size

    TFC-SR2 membrane. In contrast, the cake-enhanced concentration polarisation effect

    was more severe for the tighter NF-270 and NF-90 membranes. For hydrophobic solutes

    such as BPA, the formation of the fouling layer could also interfere with the soluteÃÂÿ

    membrane interaction, and therefore, exert considerable influence on the separation

    process.

Authors


  •   Nghiem, Long D.
  •   Vogel, Dirk (external author)
  •   Khan, Stuart J. (external author)

Publication Date


  • 2008

Citation


  • Nghiem, L. D., Vogel, D. & Khan, S. (2008). Characterising humic acid fouling of nanofiltration membranes using bisphenol A as a molecular indicator. Water Research, 42 4049-4058.

Scopus Eid


  • 2-s2.0-51349126705

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/3530

Has Global Citation Frequency


Number Of Pages


  • 9

Start Page


  • 4049

End Page


  • 4058

Volume


  • 42

Abstract


  • Fouling of nanofiltration (NF) membranes by humic acids was investigated using bisphenol

    A (BPA) as an indicator chemical to differentiate between various mechanisms that may

    lead to a change in solute rejection. Three commercially available NF membranes were

    investigated and an accelerated fouling condition was achieved with a foulant mixture

    containing humic acids in an electrolyte matrix. The effects of membrane fouling on the

    rejection of BPA were interpreted with respect to the membrane pore sizes and the fouling

    characteristics. Results reported here indicate that calcium concentration in the feed solution

    could be a major factor governing the humic acid fouling process. Moreover, a critical

    concentration of calcium in the feed solution was observed, at which membrane fouling

    was most severe. Membrane fouling characteristics were observed by their influence on

    BPA rejection. Such influence could result in either an increase or decrease in rejection

    of BPA by the three different membranes depending on the rejection mechanisms involved.

    It is hypothesized that these mechanisms could occur simultaneously and that the effects

    of each might not be easily distinguished. However, it was observed that their relative contribution

    was largely dependent upon membrane pore size. Pore blocking, which resulted

    in a considerable improvement in rejection, was prominent for the more open pore size

    TFC-SR2 membrane. In contrast, the cake-enhanced concentration polarisation effect

    was more severe for the tighter NF-270 and NF-90 membranes. For hydrophobic solutes

    such as BPA, the formation of the fouling layer could also interfere with the soluteÃÂÿ

    membrane interaction, and therefore, exert considerable influence on the separation

    process.

Authors


  •   Nghiem, Long D.
  •   Vogel, Dirk (external author)
  •   Khan, Stuart J. (external author)

Publication Date


  • 2008

Citation


  • Nghiem, L. D., Vogel, D. & Khan, S. (2008). Characterising humic acid fouling of nanofiltration membranes using bisphenol A as a molecular indicator. Water Research, 42 4049-4058.

Scopus Eid


  • 2-s2.0-51349126705

Ro Metadata Url


  • http://ro.uow.edu.au/engpapers/3530

Has Global Citation Frequency


Number Of Pages


  • 9

Start Page


  • 4049

End Page


  • 4058

Volume


  • 42