In an era where electronic waste grows as rapidly as our reliance on technology, a timely discovery emerges from the laboratories of ETH Zurich in Switzerland. Researchers have found a way to extract gold from the discarded circuits of our digital lives, employing nothing more than a byproduct of cheese production — a bodybuilder’s favorite supplement: whey.

This remarkable method not only promises a more sustainable future for e-waste recycling but also redefines the age-old quest of alchemy, transforming waste into precious metal.

A Modern Alchemy And A Sponge for Gold

At the heart of this process is a simple yet highly effective material: a protein fibril sponge derived from whey. Professor Raffaele Mezzenga and his team from the Department of Health Sciences and Technology at ETH Zurich claim that their e-waste-to-precious-metal conversion is highly efficient, cost-effective, and last but not least, environmentally friendly. That’s in contrast to traditional e-waste recycling which is energy-intensive and more often than not involves highly toxic chemicals to extract the precious metals.

The protein fibril sponges are made by denaturing whey proteins under specific conditions, leading them to form a gel of protein nanofibrils. This gel, once dried, transforms into a sponge capable of selectively adsorbing gold ions from a solution of dissolved electronic components. The beauty of this method lies in its selectivity; while other metals can adhere to the sponge, gold does so more efficiently, making the recovery process both precise and effective.

Upon absorbing the gold ions, the researchers apply heat to the sponge, initiating a reduction process that converts these ions into metallic flakes. These flakes are then melted down to form a gold nugget.

Remarkably, from the components of 20 old computer motherboards, the team successfully extracted a 450-milligram nugget of 22-carat gold, demonstrating the method’s efficiency and potential for scalability.

Towards a Greener Future

Electronic waste, or e-waste, is the fastest-growing waste stream on the planet, according to the World Health Organization. In 2019 alone, the world produced a staggering 53.6 million tonnes of e-waste, with only a meager 17.4% formally collected and recycled. E-waste contains a cocktail of hazardous materials, including lead, mercury, and flame retardants. When dumped in landfills or incinerated, these toxins can leach into the soil and water, contaminating the environment and posing a threat to human health.

The implications of this new technology extend far beyond the laboratory. By providing a method that uses upcycled materials and requires significantly lower energy and financial investment, this new type of recycling paves the way for more sustainable practices in the gold recovery industry. Moreover, it not only addresses the issue of electronic waste but also offers a new lease on life for the byproducts of the food industry.

“The fact I love the most is that we’re using a food industry byproduct to obtain gold from electronic waste,” Mezzenga said in a press release.

Looking ahead, the researchers aim to refine and scale this technology for commercial use. Their vision includes exploring other sources of waste, such as industrial byproducts from microchip manufacturing or gold-plating processes. Furthermore, they are investigating the potential of using other protein-rich waste materials to create the fibril sponges, broadening the scope of this sustainable technology. Perhaps they can tune other sponges to extract other useful metals besides gold, including copper and cobalt.

The findings appeared in the journal Advanced Materials.