Novel cellulose ester substrates for high performance flat-sheet thin-film composite (TFC) forward osmosis (FO) membranes
KAUST DepartmentWater Desalination and Reuse Research Center (WDRC)
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AbstractA novel hydrophilic cellulose ester with a high intrinsic water permeability and a water partition coefficient was discovered to construct membrane supports for flat-sheet thin film composite (TFC) forward osmosis (FO) membranes for water reuse and seawater desalination with high performance. The performance of TFC-FO membranes prepared from the hydrophilic cellulose ester containing a high degree of OH and a moderate degree of Pr substitutions clearly surpasses those prepared from cellulose esters and other polymers with moderate hydrophilicity. Post-treatments of TFC-FO membranes using sodium dodecyl sulfate (SDS) and glycerol followed by heat treatment further enhance the water flux without compromising the selectivity. Positron annihilation lifetime analyses have confirmed that the SDS/glycerol post-treatment increases the free volume size and fractional free volume of the polyamide selective layer. The newly developed post-treated TFC-FO membranes exhibit a remarkably high water flux up to 90 LMH when the selective layer is oriented towards the draw solution (i.e., PRO mode) using 1. M NaCl as the draw solution and DI water as the feed. For seawater desalination, the membranes display a high water flux up to 35 LMH using a 2. M NaCl draw solution. These water fluxes exceeded the water fluxes achieved by other types of FO membranes reported in literatures. © 2014 Elsevier B.V.
CitationOng RC, Chung T-S, de Wit JS, Helmer BJ (2015) Novel cellulose ester substrates for high performance flat-sheet thin-film composite (TFC) forward osmosis (FO) membranes. Journal of Membrane Science 473: 63–71. Available: http://dx.doi.org/10.1016/j.memsci.2014.08.046.
SponsorsThe authors would like to thank Eastman Chemical Company, USA for the provision of the synthesized novel cellulose esters. This research is also supported by the National Research Foundation, Prime Minister's Office, Singapore under its Competitive Research Program for the project entitled, "Advanced FO Membranes and Membrane Systems for Wastewater Treatment, Water Reuse and Seawater Desalination" (Grant numbers: R-279-000-336-281 and R-279-000-339-281). Special thanks are due to Dr. Shipeng Sun and Dr. Sui Zhang for their valuable advices and Ms. Xiaoman Li for her assistance in this work.
JournalJournal of Membrane Science