Highly permeable double-skinned forward osmosis membranes for anti-fouling in the emulsified oil-water separation process


Duong, Hoang Hanh Phuoc
Chung, Neal Tai-Shung
Wei, Shawn
Irish, Lana

KAUST Department
Water Desalination and Reuse Research Center (WDRC)

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Forward osmosis (FO) has attracted wide attention in recent years. However, the FO performance may be restricted due to internal concentration polarization (ICP) and fast fouling propensity that occurs in the membrane sublayer. Particularly, these problems significantly affect the membrane performance when treating highly contaminated oily wastewater. Recently, double-skinned flat sheet cellulose acetate (CA) membranes consisting of two selective skins via the phase inversion method have demonstrated less ICP and fouling propensity over typical single-skinned membranes. However, these membranes exhibit low water fluxes of <12 LMH under 2 M NaCl draw solution. Therefore, a novel double-skinned FO membrane with a high water flux has been aimed for in this study for emulsified oil-water treatment. The double-skinned FO membrane comprises a fully porous sublayer sandwiched between (i) a truly dense skin for salt rejection and (ii) a fairly loose dense skin for emulsified oil particle rejection. The former dense skin is a polyamide synthesized via interfacial polymerization, while the latter one is a self-assembled sulfonated pentablock copolymer (Nexar copolymer) layer. The resultant double-skinned membrane exhibits a high water flux of 17.2 LMH and a low reverse salt transport of 4.85 gMH using 0.5 M NaCl as the draw solution and DI water as the feed. The double-skinned membrane outperforms the single-skinned membrane with much lower fouling propensity for emulsified oil-water separation. © 2014 American Chemical Society.

Duong, P. H. H., Chung, T.-S., Wei, S., & Irish, L. (2014). Highly Permeable Double-Skinned Forward Osmosis Membranes for Anti-Fouling in the Emulsified Oil–Water Separation Process. Environmental Science & Technology, 48(8), 4537–4545. doi:10.1021/es405644u

The authors would like to thank the Singapore National Research Foundation under its Competitive Research Program for the project entitled "Advanced FO Membranes and Membrane Systems for Wastewater Treatment, Water Reuse, and Seawater Desalination" (Grant Nos. R-279-000-336-281 and R-278-000-339-281) and the Kraton Polymers, LLC. for the project entitled "Evaluation of Nexar Polymers for Water Filtration Applications" (Grant No. R-279-000-396-597). Thanks are due to Dr. C. L. Willis for his kind support and help.

American Chemical Society (ACS)

Environmental Science & Technology


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