Development of antifouling properties and performance of nanofiltration membranes modified by interfacial polymerisation

M. N. Abu Seman, M. Khayet, Nidal Hilal

Research output: Contribution to journalArticlepeer-review


Two types of bisphenol monomers, Bisphenol A (BPA) and Tetramethyl Bisphenol A (TMBPA), with different concentrations of bisphenol aqueous solution (0.5% to 2.%w/v) and various interfacial polymerisation times (10. s, 30. s and 60. s) in the fixed 0.15%w/v organic solution of trimesoyl chloride (TMC)-hexane were studied. Irreversible fouling of both unmodified polyethersulfone NFPES10 and modified polyester thin-film composite polyethersulfone membranes were studied using humic acid model solutions at two different pH values, pH 7 and pH 3. It was observed that polyester thin-film composite membranes prepared by BPA exhibited fewer tendencies for irreversible fouling by humic acid molecules at neutral environment compared to unmodified NFPES10 and TMBPA-polyester series. This is most probably due to high electrostatic repulsion force between negatively charged of BPA-polyester layer and highly negative charged of humic acid at pH7. However, some modified membranes with rougher surfaces were severely fouled by humic acid molecules at acidic environment, pH 3. Under this acidic environment, carboxylic acid groups of humic acid lost their charge and the macromolecules of humic acid have smaller macromolecular configuration due to the increased hydrophobicity and reduced inter-chain electrostatic repulsion. Thus the molecules of humic acid may be preferentially accumulated at the valleys of the rougher membrane surface blocking them and resulting in a more severe fouling. In addition, the modification also affected membrane pore size and pore size distribution as shown by AFM images. It was also observed that the smaller pore size generated after modification does not have significant effect on humic acid removal due to the larger size of humic acid molecules. All the modified membranes posses smaller pore size than the unmodified NFPES10 (1.47. nm) in the range of 0.8-1.34. nm.

Original languageEnglish (US)
Pages (from-to)36-47
Number of pages12
Issue number1
StatePublished - Jun 1 2011


  • AFM
  • Humic acid
  • Interfacial polymerisation
  • Membranes
  • Polyethersulfone

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • General Materials Science
  • Water Science and Technology
  • Mechanical Engineering


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