Breaking the Wall of Bio-Inspired Rare Earth Recovery

Breaking the Wall of Bio-Inspired Rare Earth Recovery

Global Call 2026 Finalist Interview: Physical Sciences

Victor Mougel is Professor of Bioinorganic and Bioinspired Chemistry at ETH Zurich. His research draws inspiration from metalloenzymes to design catalysts for sustainable chemical transformations. By bridging molecular chemistry, materials science, and electrochemical engineering, his group develops new strategies for the conversion of small molecules and the recovery of critical elements, from fundamental molecule and material design to practical devices.

Which wall does your research or project break?  

Rare earth elements are indispensable to many technologies required for the energy transition, including wind turbines, electric vehicles, electronics, and advanced magnets. Yet their supply still relies heavily on primary mining and on separation processes that are chemically intensive, energy demanding, and difficult to deploy locally. Recycling should provide an alternative source, but recovering individual rare earth elements from complex waste remains a major challenge because these metals have extremely similar chemical properties. Conventional processes therefore require many successive separation steps, large volumes of reagents, and substantial infrastructure.

Our research aims to break this wall by changing the chemical principles used for rare earth separation. Instead of relying only on differences in binding affinity, we use sulfur-rich, redox-active molecular ligands inspired by the function of biological metal-binding systems. These ligands can trigger selective transformations and precipitation of rare earth elements through their own redox chemistry. This provides a new way to distinguish metals that are otherwise very difficult to separate.

We have been working at turning this molecular concept into a complete recycling loop. We therefore combine selective recovery at room temperature with direct processing of complex waste streams, regeneration of the molecular components, and a Sustainability by Design approach in which waste is treated as the primary resource. The wall we seek to break is thus both scientific and technological: overcoming the intrinsic chemical similarity of rare earth elements while replacing resource- and energy-intensive extraction with a selective, circular, and potentially decentralised process.

What is the main goal of your research or project?  

The main goal of our project is to establish a new generation of rare earth recycling processes that can recover critical elements directly from complex technological waste with high selectivity, low energy demand, and minimal chemical waste. Our objective is not simply to improve an existing extraction step, but to redesign the separation process around a different chemical principle.

At the core of the project are sulfur-rich tetrathiometalate ligands whose function is inspired by biological systems in which metal binding and redox chemistry are closely coupled. Rare earth elements are traditionally considered poorly matched to sulfur-based ligands, and conventional extractant design therefore focuses primarily on maximising binding affinity. We instead exploit the redox activity of the ligand itself. By allowing the ligand to participate actively in electron-transfer processes, we can trigger selective precipitation of individual rare earth elements even when they are present in chemically complex mixtures.

Our goal is to integrate this chemistry into a complete and recyclable process. This means operating under mild conditions, ideally at room temperature; using electronic waste such as lamps, screens, and magnets as feedstocks; recovering the target rare earth elements in a small number of steps; and regenerating the molecular reagents so that they can be reused. Ultimately, we want to demonstrate that molecularly designed, bio-inspired chemistry can make urban mining both technically efficient and economically realistic, providing a circular alternative to the linear model of extracting, using, and discarding critical elements.

What impact does your research or project have on society?

Rare earth elements are essential for modern technologies, yet their production is environmentally costly and geographically concentrated. Our project aims to make electronic waste a viable local source of these critical materials.  If implemented at scale, this approach could reduce dependence on primary mining, lower the environmental footprint of rare earth production, and strengthen the resilience of supply chains. It could also create value from waste that is currently poorly recycled. We target, in this project, to ultimately keep rare earth elements in circulation, rather than treating them as materials that are mined, used once, and lost.

What advice would you give to young scientists or students interested in pursuing a career in research, or to your younger self starting in science?

Do not listen too much to people who tell you that something is impossible. If you really believe in an idea, try it, work hard on it, and keep trying until you know for yourself whether it can work or not.

Do not become too narrow too early either. Some of the most interesting ideas come from interdisciplinary approaches, or from results that initially look disappointing. A bad result for the question you were asking can sometimes be a very good result for a completely different one, if you stay curious enough to see it.

Work with people you enjoy working with, care about them, and try to understand where they are coming from. Be generous with your time, your ideas, and your credit. Your own achievements will never be diminished by recognising the people who helped make them possible.

And, maybe most importantly, have fun! Stay curious, talk to people outside your field, try your crazy ideas that may not work, and enjoy the process!

What inspired you to be in the profession you are today?

I have always been driven by curiosity and by the freedom science gives you to ask questions nobody knows the answer to. Chemistry fascinated me because you can both understand how nature works and use that understanding to create things that did not exist before.

What is one surprising fact about your research or project that people might not know?

Sulfur is usually considered a terrible choice for binding rare earth elements; it is almost a textbook example of what not to use. Yet, it is precisely the unusual redox chemistry of our sulfur-rich molecules that allows our separation process to work.

What’s the most exciting moment you've experienced over the course of your research or project?

Seeing that our chemistry could selectively recover rare earth elements directly from a real, complex waste mixture (a broken lamp collected in our department waste!) was probably the most exciting moment. It was the point at which the "fundamentally promising" concept really developed into something that could be used in real life.

Further reading

Recovery of europium from E-waste using redox active tetrathiotungstate ligands