Rare-earth elements (REEs: La–Lu, Y, and Sc) are integral to modern technology. As technological development continues, world demand for these metals will increasingly outpace supply. Consequently, new and sustainable sources are needed, as well as more efficient methods of extraction and purification. Many waste streams—mining effluents, desalination brines, e-waste, and wastewater from semiconductor fabrication plants—contain high concentrations of REEs, which could be extracted. Metal-chelating polymers have great potential in REE extraction and separation applications due to their relatively low cost and high affinity for target elements. For example, polymer-enhanced ultrafiltration is one approach where polymers selectively coordinate specific metals and ultrafiltration membranes then filter out the polymer-metal complexes. To investigate the interplay between polymer structure and metal chelation, we used isothermal titration calorimetry to directly measure the binding affinity (K<sub>a</sub>), enthalpy changes (ΔH), and stoichiometry of the interactions between a series of REEs in solution and metal-chelating polymers. These measurements enabled us to characterize the complete thermodynamic profile of these polymer-metal interactions. These experiments will inform future work on developing chelating polymers for rare-earth element extraction.

Elucidating the thermodynamics of polymer-metal interactions in solution

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.