A study led by Cornell University is exploring ways to extract gold particles from electronics waste, and then use the recovered metal as a catalyst for turning carbon dioxide into organic materials.
Details of the study were published in the Nature Communications journal, under the title Recycling e-waste into gold-loaded covalent organic framework catalysts for terminal alkyne carboxylation.
According to the researchers, the process could provide a sustainable use case for some of the 50 million tonnes of electronic waste that is discarded each year, of which just 20% is recycled.
Extracting the gold
As part of the study, Amin Zadehnazari, postdoctoral researcher and co-author of the report, synthesised a pair of vinyl-linked covalent organic frameworks (COFs) to extract gold ions and nanoparticles from circuit boards in discarded electronic devices, while disregarding other metals in said devices, such as copper or nickel.
“We can then use the gold-loaded COFs to convert CO2 into useful chemicals,” Zadehnazari commented. “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.”
Zadehnazari’s method also avoids the use of dangerous materials, with chemicals including cyanide historically used to recover gold from e-waste.
Dealing with e-waste
A tonne of electronic waste contains at least ten times more gold than the ore from which it is extracted, the study found, and with e-waste set to increase to as much as 80 million tonnes a year by the end of the decade, finding new ways to extract and utilise this precious metal is becoming increasingly important.
“Knowing how much gold and other precious metals go into these type 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,” added Alireza Abbaspourrad, the Yongkeun Joh associate professor of food chemistry and ingredient technology in the College of Agriculture and Life Sciences, and a co-author of the report.
Other co-authors include Abbaspourrad lab postdoctoral researcher Amin Zarei; former postdoctoral researcher Ataf Ali Altaf; lab research associate Ahmadreza Khosropour; Saeed Amirjalayer of the University of Munster, Germany; and Florian Auras of Dresden University of Technology, also in Germany. Read more here.
