Rare earth elements (REEs) play an essential role in advancing our society, being critical resources in various electronic devices and renewable energy technology due to their roles in permanent magnets, cars, smartphones, computers, catalysts, rechargeable batteries, among other applications. As the importance of REEs in the global economy continues to grow, efficient platforms for REE recovery and purification are becoming an increasing need. Applying electrochemical control to REE recovery systems can lead to highly modular and sustainable systems that allow for recovery without the use of additional chemical agents. For the reversible capture and release of REEs, a redox-copolymer, poly(ferrocenylpropyl methacrylamide-co-methacrylic acid), was used to combine the ion-exchange functionalities of carboxylic acid groups for REE adsorption, and redox responsive ferrocene moieties for regeneration/desorption based on electrochemical controls. The copolymer electrodes exhibited an yttrium (Y) adsorption capacity of 69.4 mg Y/g polymer, and electrochemically mediated regeneration efficiency close to 100% through oxidation of the ferrocenium units. The electrode also was shown to exhibit high uptake and recovery for various other REEs including cerium, neodymium, europium, gadolinium, and dysprosium. This work provides a generalized concept for electrochemically regenerable ion-exchange which can be extended to various other separation systems.

Ion-exchange redox-copolymers for electrochemically-mediated recovery of rare earth elements

ACS Spring 2022

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