Sandia National Laboratories Advances Porous Liquids for Methane Capture

Sandia National Laboratories is developing chemistry to capture methane from biogas, a mixture containing methane and other chemicals derived from sources like food scraps, manure, and sewage. Materials engineer Jessica Rimsza and her team are focusing on creating porous liquids that can selectively capture methane and other gases, potentially offering a supplemental domestic energy source.

How Porous Liquids Function

Porous liquids are created by combining a liquid solvent with a porous solid material, resulting in a liquid with microscopic cavities. These cavities provide internal empty space within the liquid, enabling it to absorb and store gas molecules.

Researchers can customize the liquid's properties by mixing various porous solids, such as zeolites or metal-organic frameworks, with different solvents. This customization allows for the selective capture of specific gases.

Methane Separation and Potential Uses

The research primarily targets porous liquids capable of selectively capturing methane from biogas, separating it from impurities like carbon dioxide. Once captured, methane can be extracted and used for electricity generation, heating, and industrial processes such as steel and glass production.

It can also serve as a feedstock for producing chemicals like hydrogen, methanol, ammonia, and acetylene, which are utilized in fertilizers and plastics. Earlier work by the team also involved developing porous liquids for carbon dioxide capture.

Advantages and Research Findings

The liquid form of this technology could facilitate easier integration into existing infrastructure, as it can be used in current piping systems, unlike solid porous materials. Porous liquids were first theorized in 2007 and experimentally confirmed in 2015.

Sandia's research aims to broaden their application for energy purposes, characterizing their behavior and investigating new combinations for enhanced gas absorption capacity and selectivity.

The team has observed that certain porous liquid formulations can hold substantially more gas than either the solvent or the porous solid component would individually, in some cases up to 40 times more than anticipated.

The team has filed a patent application and published journal articles related to their research. Funding for this work is provided by the Department of Energy Office of Science Basic Energy Sciences program and Sandia's Laboratory Directed Research and Development program.