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Throughout history, alchemists have been obsessed with touchstones that can turn cheap things into high-priced gold. Now, scientists from the University of Manchester, Tsinghua University and the Chinese Academy of Sciences have proved that graphene can be used as a "touchstone" to extract gold from a waste solution containing only a few billionths of gold.

This new function of graphene seems magical, but how it works is quite simple: graphene is added to a solution containing trace amounts of gold, and after a few minutes, pure gold is transferred to graphene sheets without other chemical or energy inputs. Then, pure gold can be easily obtained by directly burning graphene. The findings are published in the journal Nature Communications.

Screenshot of web page | Ref. [2] 1 gram of graphene can extract nearly 2 grams of gold. And since the price of graphene is less than $0.10 per gram, while the price of gold is about $70 per gram, it is profitable to use this method to recover gold.

"it seems to be magic, but it is essentially a simple electrochemical process," said Su Yang, a doctor at Tsinghua University who led the research. "the unique interaction between graphene and gold ions drives this process, resulting in a special selectivity, extracting only gold and no other ions."

The process of extracting trace gold from a solution with graphene. (a) after mixing with gold ion for 12 hours, the solution changes from black to brown, and the lower part is the optical image of graphene sheet before and after gold extraction. (B) the relationship between gold extraction capacity and gold content after 24 hours. The illustration shows the extraction efficiency diagram of 10 ppm gold solution under different pH. (C) the extraction capacity of 10 ppm gold solution varies over time. The inset shows the extraction value from different solutions after 10 minutes. Reference [2] Gold is used in many industries, including consumer electronics such as mobile phones and notebook computers. When such products are finally discarded, only a very small amount of resources are recycled from e-waste. The graphene-based process has high extraction ability and selectivity, and nearly 100% gold can be recovered from e-waste, which provides an excellent solution to solve the problems of gold sustainability and e-waste.

Another lead author, Professor Andre Geim, from the University of Manchester who won the Nobel Prize for the first separation of graphene, added: "graphene can really turn garbage into gold. Our findings are not only expected to make this part of the economy more sustainable, but also highlight the differences between atomic thin materials and well-known bulk materials. For example, graphite is of no value for gold extraction, while graphene is almost a touchstone. "

Cheng Huiming, an academician from the Chinese Academy of Sciences and one of the main authors of this article, also said: "with the deepening of the research on the revolutionary application of graphene, we have found that this material can be used to recover gold from electronic waste. This has brought new passion to the research community and the development of the graphene industry."

reference

[1] https://phys.org/news/2022-08-graphene-philosopher-stone-gold.html

[2] Li, F., Zhu, J., Sun, P. Et al. Highly efficient and selective extraction of gold by reduced graphene oxide. Nat Commun 13, 4472 (2022). Https://doi.org/10.1038/s41467-022-32204-4

Source: Flickr, James St. John / CC BY 2.0 (https://creativecommons.org/ licenses / by / 2.0 /)

Research team

Andre.K. Geim: professor, School of Physics and Astronomy, University of Manchester, Shenzhen International Graduate School, Tsinghua University

Newsletter author Su Yang: assistant Professor, Shenzhen International Graduate School of Tsinghua University

Newsletter author Cheng Huiming: academician of the Chinese Academy of Sciences

First author Li Fei: doctor, Tsinghua-Berkeley Shenzhen College of International Graduate School, Tsinghua University

The home page of the research group https://www.sigs.tsinghua.edu.cn/sy/

Paper information

Publish periodical Nature Communications

Release date: August 2, 2022

Paper title Highly efficient and selective extraction of gold by reduced graphene oxide

(DOI: https://doi.org/10.1038/s41467-022-32204-4)

This article comes from the official account of Wechat: I am a scientist iScientist (ID:IamaScientist), compiler: Oasis, editor: Jin Xiaoming, typesetting: Yin Ningliu

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