Group Separation of Rare Earth Elements by Protein-Functionalized Magnetic Nanoparticles

Rare earth elements (REEs) are essential for low-carbon technologies and a wide range of consumer products, yet intra-REE separation remains a critical challenge due to their similar physicochemical properties and co-occurrence in waste streams. Here, we developed a novel biosorbent, termed MNP-Hans-LanM, by immobilizing Hansschlegelia quercus-derived Lanmodulin (Hans-LanM) on the surface of SpyTag-functionalized magnetic nanoparticles (MNPs) for the separation of REEs into light and heavy groups from waste streams. The biosorbent exhibited an adsorption activity of 5.6 ± 0.8 μmol-neodynium/g-sorbent, and the adsorbed REEs could be recovered with >90% efficiency. The MNP-Hans-LanM could effectively separate representative light and heavy REE pairs and maintained >90% of activity over five adsorption–desorption cycles. Importantly, when applied to a low-grade course coal refuse natural leachate, the biosorbent selectively captured REEs and enabled enrichment of bound REEs into light and heavy REE groups without the use of hazardous solvents, resulting in 195- and 64-fold enrichment, respectively, relative to the initial REE feedstock. Results from this study contribute to the development of innovative biosorptive technologies for sustainable intra-REE separation from complex waste streams.