Case Western Reserve researcher takes next step toward helping NASA with future, longer-distance space travel
If humans are going to successfully make longer-distance space trips, it will depend on discovering and engineering new materials for continuous fresh air supply—and doing it in microgravity, without creating dust or emitting volatile substances.
Burcu Gurkan, an assistant professor of chemical engineering at Case Western Reserve University, is working on doing just that: She is using what are known as ionic liquids (salts that melt below the boiling temperature of water) in support structures (made of polymeric shells with graphene-oxide reinforcement sheets) to separate metabolically generated carbon dioxide (CO2) from air.
NASA’s current CO2-to-oxygen system was developed in the early 2000s and is still used in its capsules and aboard the International Space Station. The system selectively removes CO2 from the cabin atmosphere and filters out the breathable oxygen.
don’t want dust—it can get into other equipment downstream, or after the
filtration,” Gurkan said, referring to other critical components in the
system being developed by Gurkan and her team would replace the zeolites with
encapsulated droplets of ionic liquid
(salt in a liquid state) to continuously remove CO2.
Unique ionic liquids
Ionic liquids are remarkable to begin with because most are molten at room temperature, where ordinary table salt would have to be heated to elevated temperatures such as 600 degrees Fahrenheit to be liquified. Ionic liquids are also known to be nonvolatile, which eliminates inhalation by the astronauts.
But in the microgravity of space,
droplets of any liquid would simply fly apart. The advance being developed by
Gurkan and her collaborators is to contain the droplet of liquid salt within a
The combined droplets provide a much greater surface area for absorbing CO2 and demonstrate great CO2 removal capacity. Further, the presence of graphene-oxide in the material could provide “further scavenging of oxygen from the captured CO2 waste in the future.”
She and her
team are also having some success with a continuous filtering operation, where a
polymer-ionic liquid composite is used as a membrane.
They’re also having some challenges, though: Gurkan said since their system under development requires minimal weight and size, they are experimenting—with varying degrees of success—with different polymers to contain the ionic liquids.