Yang Qiaoli, Lau Cher Hon, Ge Qingchun
College of Environment and Resources , Fuzhou University , Fuzhou , Fujian 350116 , China.
School of Engineering , The University of Edinburgh , Robert Stevenson Road, The King's Buildings , Edinburgh , EH9 3FB Scotland , U.K.
ACS Appl Mater Interfaces. 2019 May 15;11(19):17828-17835. doi: 10.1021/acsami.9b03991. Epub 2019 May 1.
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-IM-(CH)-SONa) 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) 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.
