A new study by researchers at the University of Illinois Urbana-Champaign presents an efficient and selective electrochemical process for recovering rare platinum group metals (PGMs) from ore leachates and industrial waste streams, offering a sustainable, efficient way to recover scarce critical resources.
Why it matters
This research, led by chemical and biomolecular engineering professor Xiao Su, addresses a major challenge in clean energy and sustainable manufacturing: how to meet the increasing global demand for PGMs like platinum and palladium – which are used for many modern technologies – in the face of supply chain vulnerabilities and material scarcity. Efficient and sustainable recovery of PGMs from existing feedstocks is one approach, but current recovery methods are energy-intensive, imprecise and require harsh chemicals.
The big picture
PGMs are indispensable in catalysts for fuel cells, automotive emission control, and chemical manufacturing. In their study, the researchers describe custom-designed redox-copolymers that can achieve high selectivity between chemically similar PGMS, allowing for energy-efficient and targeted recovery. Importantly, they demonstrated that this system works not only in controlled solutions but also in complex, real-world feedstocks from spent catalysts and mining byproducts.
Unlike conventional solvent extraction or ion exchange, the team’s system couples molecular recognition with an electrochemical “switch,” allowing precise, reversible binding and release of PGMs. In their work, the researchers:
- developed redox-active copolymers that combine electron transfer capability (ferrocene) with metal-affinity ligands (thiourea, pyridine);
- achieved separation factors >20 between Pt and Pd, a level not attainable with previous polymer systems;
- demonstrated electrochemical regeneration and reusability across multiple cycles, showing strong stability under acidic and high-salt conditions; and
- validated the approach on real industrial leachates, confirming both selectivity and recyclability in practical scenarios.
“This study is one step toward building a circular materials economy where valuable elements are continuously reused instead of discarded. By showing that selectivity can be engineered into polymers and controlled by electricity, we open the door to sustainable recovery strategies not only for PGMs but also for other critical metals needed in batteries and renewable energy systems.”
– Hee-Eun Kim, postdoctoral research associate and the study’s first author.
The paper is available online at https://pubs.acs.org/doi/10.1021/acs.est.5c05610
Acknowledgments and Affiliations
This work was primarily funded by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award DE-AR0001714 (ARPA-E MINER).
Xiao Su is also affiliated with civil and environmental engineering in The Grainger College of Engineering, chemistry in the College of Liberal Arts & Sciences and the Beckman Institute for Advanced Science and Technology at the U. of I.