From Waste to Gold: Scientists Use Cheese Byproduct to Extract Gold From Electronic Waste

Not all that glitters is gold, but electronic waste can be. In the quest for sustainable solutions, a group of researchers led by Professor Raffaele Mezzenga from ETH Zurich's Department of Health Sciences and Technology has devised a method to extract gold from electronic waste using a byproduct of the cheesemaking process, according to TechXplore.

"Demand for gold recovery from e-waste grows steadily due to its pervasive use in the most diverse technical applications. Current methods of gold recovery are resource-intensive, necessitating the development of more efficient extraction materials," the researchers wrote.

From Electronic Waste to Gold

Electronic waste, abundant with valuable metals like copper, cobalt, and gold, presents an appealing opportunity for recovery amid increasing demand for precious metals. However, existing methods for gold extraction are often energy-intensive and reliant on hazardous chemicals.

Mezzenga's team, led by senior scientist Mohammad Peydayesh, developed a new approach utilizing a sponge derived from denatured whey proteins. They formed protein nanofibrils by subjecting whey proteins to acidic conditions and high temperatures, crafting a sponge with remarkable gold-extracting properties.

In laboratory experiments, the researchers salvaged electronic motherboards from old computers, extracting metal parts for gold recovery. Through an acid bath, they ionized the metals, enabling gold ions to adhere efficiently to the protein fibers within the sponge.

Subsequent heating of the sponge reduced gold ions into flakes, which were melted down to yield a nugget weighing approximately 450 milligrams, composed of 91 percent gold and the remainder copper, similar to 22 carats.

The viability of this technology is underscored by Mezzenga's calculations, which indicate procurement and energy costs are significantly lower than the recovered gold's value, making it commercially feasible.

What's Next?

Looking ahead, the researchers aim to refine the technology for market deployment, exploring various potential sources for gold extraction beyond electronic waste.

These may include industrial waste from microchip manufacturing or gold-plating processes. They also intend to investigate alternative protein-rich byproducts or waste from the food industry for sponge production.

Mezzenga highlighted the sustainable aspect of the method, emphasizing the utilization of a food industry byproduct to extract gold from electronic waste, effectively transforming two waste products into a valuable resource. This approach underscores the potential for environmentally conscious solutions in addressing pressing global challenges.

"These findings, along with life cycle assessment and techno-economic analyses of the process, run with realistic benchmarks, demonstrate the potential of AF aerogels as a novel environmentally friendly approach to address the growing demand for gold recovery from E-waste, contributing to circular economy principles and sustainable resource management," the researchers noted.

The research team's findings were published in the journal Advanced Materials.