Cornell researchers develop ‘win-win’ method for upcycling gold from electronics waste for CO2 conversion

CORNELL University researchers have developed a new method of extracting gold from electronic waste, which can then be used to convert CO2 into organic compounds.

The method, described by the researchers as a “win-win for the environment,” uses crystalline polymers to selectively extract gold ions and nanoparticles from waste central processing units (CPUs). The polymers were able to recover more than 99% of the waste’s total gold, while only extracting 5% of the nickel and 2% of the copper.

The gold was then used as a catalyst to convert CO2 into “useful chemicals”. Amin Zadehnazari, a postdoctoral researcher at Cornell University and lead author on the study, said: “By transforming CO2 into value-added materials, we not only reduce waste disposal demands, we also provide both environmental and practical benefits. It’s kind of a win-win for the environment.”

The gold-loaded polymers could be used six times as catalysts in CO2 conversion, the team found.

The research, published in Nature Communications in December, is the latest in the growing field of “urban mining”. Electronics waste is a rich source of gold, with a tonne of disposed electronics containing around ten times the amount of gold found in a tonne of ore.

Around 25% of the world’s gold is now recycled, although traditional methods use harsh chemicals such as cyanide. The latest research instead relies entirely on chemical adsorption.

A UN report last year found the amount of electronics waste is increasing five times faster than the amount of recycled precious metals.

The UN found that 62m t of electronic waste was produced in 2022, including US$15bn worth of gold. The current trajectory will see electronics waste rise to 80m t by 2030. It was also found that only 1% of rare earth demand is currently met by electronics recycling.

Alireza Abbaspourrad, a professor of food chemistry and ingredient technology at Cornell University and co-author of the latest study, said: “Knowing how much gold and other precious metals go into these types of electronics devices, being able to recover them in a way where you can selectively capture the metal you want – in this case, gold – is very important.”