Molecular Mechanisms in Specific Separation of Late Transition Metals from Rare Earth Elements

In recyclingRecycling, the separation of rare earth elementsRare earth elements (REE) from late transition metalsLate Transition Metal (LTM) represents a principal challenge. While iron can easily be separated by controlled increase in pH, separation of Co, Ni, and Cu requires application of advanced approaches including fractional crystallizationCrystallization, solvent extractionSolvent extraction, or use of solid adsorbents. The latter can be made selective by grafting of specific ligands reacting in a different manner with targeted classes of metal cations. Applying molecular modelMolecular models approach combined with advanced spectroscopic measurements, we were able to visualize principally different reaction pathways between REE and LTM in uptake by poly-amino ligands. The observed differences permit to tailor adsorbents with pronounced selectivitySelectivity on both adsorptionAdsorption and desorption of cations of interest.