A team of scientists has developed an advanced nanomaterial , composed of graphene oxide and chitosan, which allows the extraction of gold from electronic waste with an efficiency ten times higher than that of conventional methods.
This innovative material is the product of collaboration between researchers from the National University of Singapore, the University of Manchester in the United Kingdom and the Guangdong University of Technology in China.
A sponge made of graphene oxide and chitosan
[post_relacionado]The new material is a “nanocross-reactive” nanocomposite that combines two-dimensional graphene oxide and one-dimensional chitosan chains. This design allows both the absorption and reduction of gold ions without the need to apply voltage , thanks to the chemisorption processes that occur in the nanocavities of the compound.
Unlike traditional methods, which require multiple steps and the use of harsh chemicals, this nanomaterial can directly transform Au³⁺ and Au⁺ ions into solid gold (Au⁰).
Promising results in gold extraction
As noted in the study published in the scientific journal Proceedings of the National Academy of Sciences (PNAS), in the tests performed, the nanomaterial showed an extraction capacity of 16.8 g of Au³⁺ and 6.2 g of Au⁺ per gram of sponge, with a recovery efficiency of up to 99.5% , much higher than the current limit of 75% . In addition, it was shown that the material can effectively capture gold at concentrations as low as 3 ppm , offering a viable solution for industrial applications .
The use of chitosan, a biopolymer derived from sustainable sources, together with graphene , helps reduce the environmental impact associated with the recovery of precious metals in this type of waste .
The technique also has potential applications in the recovery of other valuable metals such as silver and platinum , opening the door to new methods for the treatment of industrial effluents and contaminated water.
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Source: PNAS
Photo: shutterstock