Phosphonated Polymers for Rare Earth Separations
This project develops a scalable, electric-field driven separation platform for separating individual rare earth element (REE) cations to address a critical bottleneck in technology supply chains. Current REE purification relies on multistage solvent extraction processes that are energy-intensive, chemically wasteful, and geopolitically constrained. We propose to design phosphonate–sulfonate ionomer membranes and resin wafers that selectively coordinate and transport REE cations under applied electric fields. By coupling these materials with shockwave electrode ionization (SEDI), a continuous and low-chemical input separation platform, we aim to achieve efficient REE/REE separations that are not possible with conventional methods. The research integrates polymer chemistry, ion transport physics, and electrochemical engineering to uncover design rules linking molecular interactions to process-scale performance. Outcomes include new materials, mechanistic insights, and a benchtop demonstration of continuous REE fractionation. The anticipated outcome of the project may help realize resilient critical mineral supply chains that are essential for climate technologies.
“Rare earth elements are essential to energy and defense technologies, including electric-drive motors, wind turbine generators, communication systems, and advanced batteries. However, separating individual rare earth elements remains one of the most difficult and chemically intensive separation processes, making it critical to establish resilient critical-minerals supply chains. With support from the Institute for Climate and Sustainable Growth, our team will develop new selective adsorbent materials and integrate them with electrokinetic separation processes to fractionate individual rare earth elements. If successful, this project could reduce chemical waste, enable recovery from more diverse domestic and recycled feedstocks, and strengthen U.S. access to critical minerals.”
Christopher Arges, CASE Senior Scientist Affiliate, Pritzker School of Molecular Engineering