Nanofibers in Osmotic Membranes for Sustainable Water and Energy
Ngoc Bui, Lawrence Livermore National Laboratory, Livermore, CA
Jeffrey R. McCutcheon, University of Connecticut, Chemical and Biomolecular Engineering Department, Storrs, CT
To address global problems associated with water scarcity, new effective methods of producing water at low energetic and environmental costs are essential. Forward osmosis has recently gained increasing attention due to its various advantages in sustainable water, resource and energy production. Developing robust membranes with effective and controlled structures for osmotic transport is imperative for widespread adoption of this technology platform. Here we report a scalable approach to fabricate osmotic thin-film composite membranes with high permselectivity based on nanofibers and nanocomposite thereof. Nanofiber has recently emerged as an exciting platform for forward osmosis membranes. Possessing a high porosity, low tortuosity and an interconnected porous structure, nanofibrous mats exhibit exceptionally low structural parameters. This work highlights recent efforts to develop nanofiber-related materials for use in forward osmosis and pressure-retarded osmosis. Our best membranes showed an outstanding permselectivity, exceeding those reported in academic literature. Specifically, these membranes show a remarkable 7-fold and 3.5-fold enhancements in osmotic water permeability and water/sodium chloride selectivity, respectively, compared to standard commercial forward osmosis membranes. These new membranes, if tuned appropriately to further increase mechanical integrity, may help enable forward osmosis to effectively function in processes related to water treatment, desalination and power production.
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