Purification of Gas with Liquid Ionic Compounds

Tech ID: 0193

Inventors: Dr. Edward Maginn and Dr. Joan Brennecke 

Date Added: August 22, 2019


A method for purifying a gas stream using a liquid ionic compound.

Technology Summary

Natural gases captured at the wellhead contains contaminants such as ethane, butane, propane, carbon dioxide, and water. The gas streams must be purified of the contaminants which may interfere with the end-use of the purified gas. Current purification methods rely on a series of binding agents, such as amines, which trap impurities based on chemical affinity and must employ a separate agent for the removal of each impurity. The addition of specific binding agents increases process time and operating costs.

University of Notre Dame researchers have developed a superior method for purifying a gas by contacting the gas with a liquid ionic compound. Ionic Liquids (ILs), salts that are molten at room temperature, are capable of impurity removal based on the variable solubility of different gases. ILs are more efficient and less toxic than current compounds used for gas purification.  The ILs demonstrate high solubility towards CO2 and water vapor allowing for the purification of a gas stream, such as natural gas, with these common impurities. The desired gas is enriched and is not affected due to its negligible solubility. The difference in gas solubility, which is specific to the IL, drives the absorption of one gas over the other, leaving behind a pure gas. Importantly, ILs have immeasurably low vapor pressures and therefore their vapor does not carry over into a gas stream. The liquids can be pumped through a system allowing for a continuous process which avoids the complexities and inefficiencies of batch process purification. 

Market Advantages 

  • Ionic liquids are simpler and cheaper to operate than other separation media
  • Separate out multiple impurities in a single step
  • Allow for purification near extraction point

Technology Readiness Status

TRL 4 - Lab Validation

Intellectual Property

US Patent 6,579,343 (Purification of Gas with Liquid Ionic Compounds)


Richard Cox