New sponge-like material can extract 10x more gold from e-waste
A team of scientists from the National University of Singapore, Manchester University in the UK, and Guangdong University of Technology in China, has developed a novel sponge-like material. The innovative material, made from graphene oxide and chitosan, has shown remarkable efficiency in extracting gold from electronic waste (e-waste), their study published in the Proceedings of the National Academy of Sciences reported.
A cleaner and more efficient method for gold extraction
The extraction of precious metals such as gold and silver from discarded electronic equipment is no easy task. Conventional methods often result in low returns and harmful pollutants. However, this new sponge-like material provides a more cost-effective, environmentally friendly, and efficient solution for gold recovery from e-waste. The research team deliberately chose graphene oxide and chitosan for their proven effectiveness in similar applications.
Unique properties of graphene oxide and chitosan
Graphene oxide is known for its ion absorption capabilities, while chitosan (a natural biopolymer) acts as a reducing agent. In this case, chitosan catalytically transforms gold ions into their solid form. The researchers created a composite by allowing the chitosan to self-assemble on two-dimensional graphene flakes. This also created sites on the material that could bind with gold ions.
Testing the sponge's efficiency with real e-waste
The researchers tested their sponge on real e-waste supplied by a recycling company. The e-waste was turned into a solution mixture with other materials from the electronic equipment. Before treatment, gold concentrations were recorded at three parts per million (ppm). The novel sponge was able to extract around 17g/g of Au3+ ions and a little over 6g/g of Au+. These amounts, the team says, are nearly 10 times higher than any other known extraction method.
