Electricity-driven molecule cuts chemicals 100x, recovers 89% gold from e-waste

Researchers at the University of Illinois Urbana-Champaign have developed a molecule that uses electricity to drive metal extraction, potentially reducing the chemical reagents needed to recover valuable metals from electronic waste, mining streams and industrial waste. The molecule combines three functions in one structure. It can selectively bind metal ions, carries a permanent electrical charge and remains soluble in the organic liquid used during extraction. That built-in charge allows electricity to directly control the molecule during the separation process. Instead of relying on additional chemical reagents to trigger the reactions needed to capture and release metals, the researchers can use an electrical signal. The team demonstrated the approach by selectively recovering gold from electronic-waste leachates, showing how an extraction process traditionally dependent on chemical inputs could be electrically controlled. One molecule does three jobs The work builds on a 2024 system developed by the same research group for continuous electrochemically mediated liquid-liquid extraction, or e-LLE. That process used electricity to replace many acids and bases involved in conventional metal extraction, but still required additional chemical reagents to complete the cycle. The new approach removes that remaining step by changing the extraction molecule itself. “The new molecule has a permanent built-in charge that acts as electrolyte, letting the liquid conduct electric current,” explained postdoctoral researcher Deborah Schmitt, a co-author of the paper. “That’s what allows the redox reactions to be driven by electricity instead of chemicals. This work completely electrifies a separation process that industry heavily depends on chemical reagents to perform.” The molecule can first be electrically activated to bind a target metal and move it into an organic phase. A change in its electrical state can then release the metal, allowing the extraction cycle to continue without the intermediate chemical reagents used in conventional approaches. “This is the first time we’ve been able to run electrochemical solvent extraction the way we dreamed of,” Su said. “We charge the molecule, it binds the metal, moves it into the organic phase, and then electricity releases it again.” The researchers say the approach reduced chemical consumption by one to two orders of magnitude. Cutting those chemical inputs could reduce waste while also simplifying the extraction process. Gold was used as the demonstration case, but the researchers say the molecular design could be adapted to separate other valuable metals. These include platinum-group metals found in spent automotive catalysts and potentially critical elements present in mine tailings and other complex waste streams. “This system can be adapted to selectively recover many different valuable metals, like platinum-group metals from spent automotive catalysts and potentially a number of other critical elements from mine tailings or other complex feedstocks,” said graduate student and co-author Aderiyike Aguda. “Since the electrochemical platform remains largely the same, the chemistry of the extractant can be tailored to target different metals depending on the application.” The key advance is therefore not simply recovering gold with electricity. It is the development of a molecular framework that can be tuned for different metals while keeping the underlying electrochemical process largely unchanged. “Basically, this work unlocked the fundamentals behind it – how to think about it,” Su said. The researchers are now working on new molecule designs and studying how the process could be scaled for industrial applications. The team is also exploring computational modeling and artificial intelligence to accelerate the discovery of extraction molecules. “I’m really excited about this work because I think it shows one more step toward demonstrating that electrochemistry can actually offer scalable, minimal-waste separations,” he said. “With growing attention on critical minerals and supply chains, it’s a step toward rethinking how we recover metals in a way that’s cleaner and fully electrified.” The study was published in ACS Energy Letters. Get the latest in engineering, tech, space & science - delivered daily to your inbox.With over a decade-long career in journalism, Neetika Walter has worked with The Economic Times, ANI, and Hindustan Times, covering politics, business, technology, and the clean energy sector. Passionate about contemporary culture, books, poetry, and storytelling, she brings depth and insight to her writing. When she isn’t chasing stories, she’s likely lost in a book or enjoying the company of her dogs.