The paper's key innovation uses membranes -- amorphous fluorinated polymers, to be specific -- that efficiently isolate complex refrigerant mixtures. Other separation methods, like distillation, are less effective because of the complex composition of the mixtures. Harders said the membranes are fabricated to allow some gases to pass through while restricting others, resulting in effective purification. 

To demonstrate the technology could scale to industrial viability, the team -- including many associated with KU’s Wonderful Institute for Sustainable Engineering -- developed a custom-coating process to create submicron coatings on the membrane’s porous supports, creating composite hollow fibers. The results show a functional prototype, proving the technology’s usefulness to firms engaged in refrigerant recovery and reuse. 

Harders cited international agreements and legislation like the Kigali Amendment to the Montreal Protocol and the AIM Act that will phase out HFC production as the ultimate solution to atmospheric warming from refrigerants. In the meantime, solutions for dealing responsibly with complex gases in existing equipment destined for landfills around the world are badly needed, she said. 

“A large percentage of refrigerant today is not recovered -- it’s simply vented into the atmosphere,” she said. “Much of this occurs when equipment is decommissioned. In some cases, recovering refrigerant may not seem worthwhile, or those responsible for recovery may not recognize its value. Additionally, if refrigerant is not fully evacuated, it can end up in landfills, where it eventually leaks into the atmosphere. Approximately 90% of refrigerant leakage occurs at the end of a system's life.” 

Harders said she hopes the method she largely devised in her time at KU could help bridge the gap ahead of the next generation of refrigerants. 

“To increase reusability and allow for the extraction and recycling of HFC refrigerants from end-of-life units, it’s essential to separate them effectively so they can be purified and reintroduced into the market,” she said. “However, no existing industrial technology can currently achieve this. These refrigerants form complex mixtures that cannot be separated using traditional heat-driven methods like distillation.” 

Today, Harders works as a chemical engineer and head of research and development with Lawrence, Kansas-based Icorium Engineering, a startup that emerged from the Shiflett Research Group situated in KU’s Innovation Park. While Icorium focuses on separation of refrigerants using ionic liquids, the new method demonstrated in Harders’ paper offers a new tool to the industry. 

“Part of Abby’s Ph.D. research at KU is now being translated into the startup company,” said Shiflett, who co-founded Icorium and now serves as its chief science officer. “Abby also has a fascinating education journey. She’s published 10 papers and is a co-inventor on a patent application. Needless to say, I’m very proud of her and her research and journey.”