Researchers at ETH Zurich have pulled a 450-milligram nugget of 22-carat gold from the guts of 20 old computer motherboards. The trick? A spongy material made from whey protein — a byproduct of cheese production.
How the aerogel works
The team, led by professor Raffaele Mezzenga, developed a whey-protein amyloid aerogel. Think of it as a super-absorbent sponge made from denatured whey proteins. When placed in a solution of dissolved electronic waste, the aerogel grabs gold ions out of the liquid. The researchers then heat the gel, reducing the ions into solid gold flakes that can be melted into a nugget.
In lab tests, the method recovered a 450-milligram nugget of 22-carat gold from metal parts taken from 20 old computer motherboards. That’s roughly the weight of a small paperclip — but in pure gold.
Why e-waste is a target
Electronic waste is packed with valuable metals, but current recycling methods often rely on harsh chemicals and high energy use. The ETH Zurich approach uses a protein-based material that’s both cheap and biodegradable. The aerogel itself is made from whey, a waste product of the dairy industry. So the process tackles two waste streams at once: old electronics and dairy byproducts.
The research was published in 2024 in the journal Advanced Materials. It’s still at the lab stage, but the team sees potential for scaling up. They’re now looking at how to recover other precious metals from e-waste using similar protein-based materials.
What’s next
Mezzenga and his group plan to test the aerogel on larger batches of e-waste. They also want to see if the method can be adapted for metals like palladium and platinum. For now, the 22-carat gold nugget sits in the lab — a shiny proof of concept that turns trash into treasure.
