Molecular layer-by-layer assembled forward osmosis membranes

Soon Bum Kwon, Jong Suk Lee, Soon Jin Kwon, Seong Taek Yun, Seockheon Lee, Jung-hyun Lee

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

A recently devised, molecular layer-by-layer (mLbL) approach based on the alternative cross-linking of monomers was employed to fabricate high-performance thin film composite (TFC) forward osmosis (FO) membranes with excellent rejection toward monovalent NaCl salt. An ultrathin and highly dense polyamide (PA) selective layer with a precisely controlled structure was created on a tailored porous support via mLbL. The intrinsic separation properties of the mLbL-assembled TFC membranes were tuned by adjusting the mLbL cycle number to optimize the FO performance. The best FO performance was achieved at 10 mLbL cycles (mLbL-10), where the permeability and selectivity were properly balanced. Importantly, the mLbL-10 membrane exhibited superior FO performance compared to the commercial HTI FO membranes as well as hand-cast TFC membranes prepared by the conventional interfacial polymerization: the mLbL-10 membrane showed ~3.5 times higher water flux, ~60% lower reverse salt flux and ~85% lower specific salt flux compared to the cellulose triacetate HTI membrane, with 0.5. M NaCl draw solution and DI water feed solution in FO mode. The stability and the associated membrane performance of the mLbL-assembled membrane depending on the ionic strength of the environment were explained by the swelling behavior of the polyelectrolyte-assembled interlayer adhered underneath the PA selective layer.

Original languageEnglish
Pages (from-to)111-120
Number of pages10
JournalJournal of Membrane Science
Volume488
DOIs
Publication statusPublished - 2015 Aug 5

Keywords

  • Desalination
  • Forward osmosis
  • Molecular layer-by-layer
  • Polyamide
  • Thin film composite membranes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Science(all)
  • Biochemistry
  • Filtration and Separation

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