Dynamic micellar enhanced ultrafiltration: Use of anionic (SDS)-nonionic(NPE) system to remove Cr3+ at low surfactant concentration

Mohamed Aoudia, Nora Allal, Ahcene Djennet, Leila Toumi

Research output: Contribution to journalArticle

86 Citations (Scopus)


Ultrafiltration experiments were carried out with tangential cell system. The permeate flux and rejection characteristics of SDS and nonylphenol ethoxylated C9H19C6H4(CH2CH 2O)5CH2CH2OH (NPE) micellar solutions for a ceramic tubular membrane (zirconium oxide-Titanium oxide) were investigated. For both surfactants, micelle rejection increased with pressure and reached an asymptotic value at ΔP=250kPa beyond which micellar rejection remained unchanged (∼+99%). This was explained in terms of concentration polarization occurring in the vicinity of the membrane-solution interface. Time dependence of the permeate surfactant concentration was also investigated. During the first 2h of ultrafiltration, the surfactant concentration changed with time. Then a steady-state condition was reached and the permeate concentration remained invariant. This trend was attributed to a time-dependent gradual change of the state of packing of the micelles over the membrane surface. Cr3+ rejection by SDS-NPE mixed micelles yielded high Cr3+ rejection (+99.5%) at NPE molar fraction up to 0.2. Within this optimum composition and ΔP=250kPa, unexpectedly high rejection (33.50%) was measured below the critical micellar concentration (cmc). This was considered as due to a high surfactant concentration in the vicinity of the membrane surface where micelles are present, although the retentate surfactant concentration is below the cmc. Above the cmc, high Cr3+ rejections (+99%) were obtained. Interestingly, this rejection was found to be independent of the feed surfactant concentration within the range investigated in this study (3×cmc-30×cmc), suggesting that Cr3+ rejection is not a function of the surfactant concentration in the bulk retentate solution but a function of the surfactant concentration nearby the membrane surface. The presence of NaCl in the feed surfactant solution showed a drastic adverse effect on Cr3+ rejection by SDS-NPE micelles.

Original languageEnglish
Pages (from-to)181-192
Number of pages12
JournalJournal of Membrane Science
Issue number1-2
Publication statusPublished - Jun 1 2003


  • Concentration polarization
  • MEUF
  • Micelle rejection
  • Permeate flux

ASJC Scopus subject areas

  • Filtration and Separation
  • Polymers and Plastics

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