2025 AIChE Annual Meeting

(476a) Peptide Surfactants for Foam-Based Rare Earth Element Separation

Author

Dr. Kathleen J. Stebe - Presenter, University of Pennsylvania
The rare earth elements (REEs), essential components of a range of green technologies, are extremely challenging to separate and purify as they are typically present in a +3-oxidation state and are similar in size. Current separation methods are neither highly selective nor green. We have been studying peptide surfactants based on EF-hand binding motifs that were developed to bind preferentially to particular REE cations by forming a multi-dentate coordinating loop around the cations. We aim to exploit these peptides as surfactants that bind selectively to the REE cations in foam-based REE recovery schemes. Our vision is to use the peptide surfactants to bind REE cations in the bulk, to retain the REE cations in the binding loop, and adsorb at the interfaces of rising bubbles for selective REE capture. Recent progress in realizing this vision is presented regarding peptide-cation binding, cation retention, peptide:REE complex adsorption, selectivity in the bulk and at the interface, and the outlook for selective separation. This research is supported by DOE-BES BES Award DE-SC0022240 to a collaborative team of researchers at Penn, CCNY, Northwestern and UIC.