A material made of graphene oxide and chitosan allows for the extraction of gold from electronic waste with extremely high yields and without waste

Three universities discover how to extract gold from electronic waste without polluting
To extract gold from electronic waste, sometimes all it takes is… a swipe of a sponge. An international team of chemists and material scientists has developed a composite material made of graphene oxide and chitosan, a natural biopolymer already used in the pharmaceutical and food industries. The process causes the chitosan to self-assemble on two-dimensional graphene flakes. The combination of these two materials allows the sponge to effectively absorb gold ions and transform them into solid particles, ready to be collected without the need for toxic chemical reagents. Graphene is known for its ability to absorb metal ions, while chitosan plays a reducing role, catalytically converting the gold ions into their solid form.
The research, conducted by the National University of Singapore in collaboration with the University of Manchester and Guangdong University of Technology, was published in the scientific journal Proceedings of the National Academy of Sciences.
A New Dawn for Precious Metal Recovery from E-Waste
Extracting gold from electronic waste, such as discarded mobile phones and computers, is a complex process. Until now, it has almost always resulted in low yields and harmful pollutants. The graphene and chitosan sponge, however, represents a breakthrough: during tests, the new device demonstrated the ability to extract up to 17 grams of Au3+ ions per gram of sponge and over 6 grams of Au+. These values are about ten times higher than those of traditional methods.
To verify the sponge’s effectiveness, the researchers used real electronic waste provided by a recycling company. Even with complex materials, the sponge was able to extract gold quickly and without waste.
According to the scientists, this discovery represents a significant step forward towards more sustainable and efficient electronic waste recycling. As readers of Rinnovabili are well aware, this is a critical area given the global growth of electronic devices. If implemented on an industrial scale, the sponge could drastically reduce the environmental impact of precious metal extraction.