Researchers have developed a new type of material that’s 10 times more efficient at extracting gold from e-waste than previous adsorbents. Developed by chemists and materials scientists at the National University of Singapore, the material is a type of sponge made of graphene oxide and chitosan.
The material can reportedly transform the way gold is extracted from electronic wastes, which has been described so far as a dirty business with low yields and results in toxic pollutants.
The cheaper, cleaner and efficient method was tested by researchers using real e-waste provided by a recycling company.
“We developed unique, composite materials capable of not only extraction but also reduction of gold from e-waste,” said researchers in the study published in Proceedings of the National Academy of Sciences.
“Providing simultaneous chemisorption and chemical reduction of gold from e-waste without applying any power, our approach creates economic value from otherwise discarded items.”
The newly developed sponge was able to extract approximately 17g/g of Au3+ ions and a little more than 6 g/g of Au+. Such amounts, the team claims, are approximately 10 times that of any other known extraction process.
Nanoscale cross-dimensional composite material
Researchers stated that large efforts are applied for the recovery of gold (Au) from e-waste using critical processes which include the dissolution of Au, its adsorption in an ionic state and succeeding reduction to metallic Au.
They developed a nanoscale cross-dimensional composite material via self-assembly of two-dimensional graphene oxide and one-dimensional chitosan macromolecules, capable of acting simultaneously as a scavenger of gold ions and as a reducing agent, according to the study.
“Such multidimensional architecture doesn’t require to apply any voltage for Au adsorption and reduction and solely relies on the chemisorption kinetics of Au ions in the heterogeneous GO/CS nanoconfinements and their chemical reduction on multiple binding sites. The cooperative phenomena in ionic absorption are responsible for the extremely high efficiency of gold extraction,” said researchers.
Innovation in gold recovery enhances efficiency and sustainability
They maintained that this innovation in gold recovery not only enhances efficiency and sustainability but also marks a significant advancement in developing eco-friendly solutions for managing e-waste and conserving natural resources.
While the present work focused on gold, the team say the technique could be adapted to recover other valuable metals such as silver, platinum or palladium from electronic waste or even mining residues. And that is not all: as well as e-waste, the technology might be applied to a wider range of environmental cleaning efforts, such as filtering out heavy metals from polluted water sources or industrial effluents, reported Physics World.
Researchers from Manchester University in the U.K. and Guangdong University of Technology in China also participated in the study.