(531c) Structured Ligand Design for the Selective Recovery of Critical Elements from Unconventional Feedstocks Via Sustainable CO2-Facilitated Reactive Separation Pathways

Energy-relevant metals, such as rare earth elements, are essential in building renewable energy infrastructures that are critical for achieving net-zero carbon emissions. However, current industrial mining practices for these metals are unsustainable and have adverse environmental impacts. As such, alternative feedstocks and greener hydrometallurgical processes are needed to extract and recover these metals sustainably. End-of-life materials such as waste-to-energy ashes and electronic wastes are examples of valuable unconventional feedstocks for these metals that are readily available. In this context, our work focuses on exploring the selective recovery of critical elements from these feedstocks, particularly rare earth elements, through structured ligand design in solvent extraction or functionalized hybrid systems. The selectivity towards rare-earth elements against a large background of competing ions will also be investigated. In particular, the use of reactive separation strategies utilizing CO₂ as a sustainable acid to regenerate the ligands and precipitate recovered lanthanides as valuable products (e.g., carbonates, oxides) will be highlighted.