Key Takeaways
ETH Zurich recovered a 450 mg 22-carat gold nugget from 20 motherboards in 2024.Raffaele Mezzenga’s whey aerogel might decrease e-waste recycling prices by as much as 50x.With 61.3M tons of e-waste in 2023, Superior Supplies spotlights scalable restoration.
That previous cellphone or lifeless laptop computer you retain that means to recycle is richer than most gold ore, a minimum of on a per-ton foundation. In March 2024, researchers at ETH Zurich led by Professor Raffaele Mezzenga confirmed they may pull gold ions out of an acid-dissolved electronics cocktail utilizing a sponge constructed from whey protein, a cheesemaking byproduct, dried right into a porous aerogel. In a lab run utilizing steel components from 20 discarded pc motherboards, the staff recovered a 450 milligram nugget of 22-carat gold, work later printed in 2024 in Superior Supplies. The timing issues as a result of the pile retains rising: international e-waste hit about 61.3 million tons in 2023.
Turning meals waste right into a supplies breakthrough
So what does a cheese byproduct should do along with your previous laptop computer? Again in March 2024, researchers at ETH Zurich sketched a surprisingly direct reply: use leftover whey proteins to tug gold out of dissolved electronics, a twist on recycling that reads like kitchen chemistry however targets a really fashionable pileup of gadgets.
The staff was led by Professor Raffaele Mezzenga in ETH Zurich’s Division of Well being Sciences and Know-how, with senior scientist Mohammad Peydayesh among the many research’s authors. ETH Zurich laid out the strategy in its March 2024 information launch, after the paper appeared within the journal Superior Supplies in 2024.
A sponge that prefers gold
The core trick is a protein “sponge” constructed from whey. Researchers denature whey proteins underneath acidic situations and excessive temperatures, forming protein nanofibrils, then dry them right into a extremely porous amyloid aerogel that may selectively adsorb gold ions from a mixed-metal answer.
In lab testing, the aerogel confirmed a gold adsorption capability of 166.7 milligrams of gold per gram of aerogel, per an ADS summary of the work. One business report additionally described the tactic as capturing 93% of gold from answer, with the loaded sponge reaching about 20% of its personal weight in gold.
From 20 motherboards to a small nugget
To show the method, the ETH Zurich staff salvaged steel components from 20 previous pc motherboards, then dissolved them in an acid tub to ionize the metals earlier than exposing the answer to the whey-based sponge.
The consequence was tangible: a 450-milligram nugget of 22-carat gold recovered from these 20 boards. It’s a small mass, but it surely’s the form of proof level recyclers and supplies scientists watch intently as a result of it reveals selectivity in a messy, real-world combine.
Why this issues for the US e-waste mountain
The gold argument hinges on focus. Trade reporting has described e-waste as containing as much as 100 instances extra gold per ton than materials pulled from gold mines, making discarded electronics an “city mine” within the literal sense.
Scale is the opposite stress: international e-waste era was estimated at 61.3 million tons in 2023, a determine cited in protection of the work by Anthropocene Journal. Mezzenga framed the inputs plainly, saying, “our strategy makes use of meals by-products, so the beginning uncooked supplies are extraordinarily cheap and sustainable.” His calculations additionally instructed procurement and power prices have been 50 instances decrease than the worth of the recovered gold, and the method avoids cyanide and mercury.
