Mixed polymer-coated magnetic manoparticles as forward osmosis draw agents of tuned hydrophilicity

Priyanka Dey*, Emad L. Izake

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We recently reported a polymer-coated magnetic nanoparticle (MNP) draw agent for the forward osmosis (FO) water desalination process. The water flux was found to increase when the polymer poly(sodium acrylate) (PSA) was anchored to the MNP surface as compared to the polymer (or polyelectrolyte solution) alone, due to the polymer chains being stretched out and most of the hydrophilic groups on the polymer contributing to water flux. We herein report the use of a secondary polymer poly(N-isopropylacrylamide) PNIPAM to manipulate the PSA polymer conformation and influence inter- and intrachain interactions to enhance the efficiency of the FO draw agent. These PSA–PNIPAM-coated MNPs generated a much higher water flux of ∼11.66 LMH when compared to the 100 % PSA-coated MNPs featuring a value of ∼5.32 LMH under identical FO conditions. The osmotic pressure and water flux driven by the mixed polymer-coated MNPs were found to be a strong function of the net polymer coverage on MNPs, that is, net available hydrophilic groups. Our new draw agent demonstrates potential for use in the water industry due to its improved efficiency and cost effectiveness as it uses only ∼0.062 % (w/v) of the draw agent solution.

Original languageEnglish
Pages (from-to)11253-11260
Number of pages8
JournalChemistry - A European Journal
Issue number32
Early online date4 Jul 2016
Publication statusPublished - 1 Aug 2016


  • forward osmosis
  • polymer-coated magnetic nanoparticles
  • PSA
  • water desalination


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