Novel Ionic Grafts That Enhance Arsenic Removal via Forward Osmosis

Qiaoli Yang, Cher Hon Lau, Qingchun Ge*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Current forward osmosis (FO) membranes are unsuitable for arsenic removal from water because of their poor arsenic selectivity. In this study, we designed and synthesized a series of novel imidazolium-based ionic liquids via one-step quaternization reactions and grafted these novel compounds on to conventional thin-film composite FO membranes for treatment of arsenic-containing water. The newly developed ionic membranes contained a functionalized selective polyamide layer grafted with either carboxylic acid/carboxylate or sulfonate groups that drastically enhanced membrane hydrophilicity and thus FO water permeation. Ionic membranes modified with sodium 1-ethanesulfonate-3-(3-aminopropyl) imidazolium bromide (NH 2 -IM-(CH 2 ) 2 -SO 3 Na) outperformed pristine membranes with higher water recovery efficiency. Exceptional performance was achieved with this ionic membrane in FO arsenic removal with a water flux of 11.0 LMH and a rejection higher than 99.5% when 1000 ppm arsenic (HAsO 4 2- ) as the feed with a dilute NaCl solution (0.5 M) as the draw solution under the FO mode. Ionic membranes developed in this work facilitated FO for the treatment of arsenic-containing water while demonstrating its superiority over incumbent technologies with more efficient arsenic removal.

Original languageEnglish
Pages (from-to)17828-17835
Number of pages8
JournalACS Applied Materials and Interfaces
Issue number19
Early online date19 Apr 2019
Publication statusPublished - 15 May 2019


  • arsenic removal
  • FO membrane
  • forward osmosis
  • ionic liquid
  • membrane modification
  • water treatment


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