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Thin Ionic Liquid Film Deposition Within Porous Substrates

National Energy Technology Laboratory

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Technology Marketing Summary

NETL researchers are currently developing ionic liquid technologies for application to carbon capture or other separation processes. Ionic liquids can function as a platform for an amazingly diverse set of applications, including batteries, processing of polymers and cellulose, waste water treatment, and gas separation. These patent pending technologies are available for licensing and/or collaborative research opportunities between interested parties and the U.S. Department of Energy’s National Energy Technology Laboratory.


Technology development has widened in scope to focus beyond creating better products to also considering sustainability. As this shift has occurred, ionic liquids (ILs) have received greater interest for a wide variety of applications, as ILs have the ability to replace hazardous materials that emit volatile organic compounds. Ionic liquids are essentially liquid nonvolatile salts with unique chemical and physical properties such as tunable solubility, negligible vapor pressure, thermal stability, and variability. In fact, it has been estimated that there are 1018 possible ionic liquids, and a tremendous amount of highly successful research has gone into developing ILs for a huge number of separations. 

For commercially practical separation technologies, ILs typically function as solvents. Although this approach is viable, the high cost of ILs and their unique characteristics lend themselves better to application as transport media in membranes. Membranes, the next generation of gas separation devices, have the advantages of relatively simple process control and favorable energetics, but these advantages come at the cost of increased demands on materials. However, using ILs in membrane functions is challenging, as supported ionic liquid membranes (SILMs) are difficult to produce in thin, stable membrane layers. 

NETL inventors have solved this problem by creating a method for depositing thin liquid layers within the pores of a thick porous substrate. The method creates the equivalent for a commercially viable asymmetric membrane, but with a liquid, rather than a solid, active layer. In doing so, the new technique makes many classes of supported liquid membranes, including SILMs, practical for gas separations, lowering the cost of gas separation while maintaining effectiveness.

  • Makes many classes of supported liquid membranes practical for gas separations, lowering the cost of gas separation while maintaining effectiveness
  • Gas transport in liquids is an order of magnitude faster than current polymer-based membrane techniques
  • Can be customized for a variety of separations
Applications and Industries
  • Gas separation, including CO2 capture and natural gas sweetening
  • Waste water treatment
  • Electrochemical and battery applications, including deposition of metals
More Information

U.S. Patent No. 9,186,854 issued November 17, 2015, titled "Method of Fabrication of Supported Liquid Membranes".

Inventors: David Luebke, Christina R. Myers, Lei Hong

U.S. Non-Provisional Patent Application No. 13/858,300, filed April 8, 2013, titled "Supported Liquid Membranes Having a Thin Selective Liquid Layer."

Inventors: David Luebke, Christina R. Myers, Lei Hong

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 9,186,854
Method of fabrication of supported liquid membranes
Method for the fabrication of a supported liquid membrane having a dense layer in contact with a porous layer, and a membrane liquid layer within the interconnected pores of the porous layer. The dense layer is comprised of a solidified material having an average pore size less than or equal to about 0.1 nanometer, while the porous layer is comprised of a plurality of interconnected pores and has an average pore size greater than 10 nanometers. The supported liquid membrane is fabricated through the preparation of a casting solution of a membrane liquid and a volatile solvent. A pressure difference is established across the dense layer and porous layer, the casting solution is applied to the porous layer, and the low viscosity casting solution is drawn toward the dense layer. The volatile solvent is evaporated and the membrane liquid precipitates, generating a membrane liquid layer in close proximity to the dense layer.
National Energy Technology Laboratory 11/17/2015
Technology Status
Development StageAvailabilityPublishedLast Updated

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To: Jessica Lamp<>