Elastin-Based Hydrogel for Selective Adsorption of Rare Earth Elements.

The sustainable separation of rare earth elements (REEs) from complex mixtures remains a critical technological challenge. Biomaterials offer a promising route, but their deployment has been hindered by their limited stability and efficiency. Here, we report a robust elastin-based hydrogel incorporating the lanthanide-binding protein, lanmodulin, for efficient and selective REE separation. A fusion protein of elastin-like polypeptide and lanmodulin was synthesized and cross-linked with four-arm polyethylene glycol to form a porous network that enhances REE binding and release in aqueous environments. The protein-cross-linked hydrogel exhibits high internal selectivity for lanthanide ions over multiple regeneration cycles. When implemented as an ion exchange chromatography adsorbent, it enables the selective fractionation of lanthanides from allanite ore, a complex natural source containing abundant REEs and non-REEs. The combination of excellent selectivity and operational stability positions this protein hydrogel as a sustainable platform for eco-friendly REE separation and purification.