It's not every day that someone looks at a piece of cheese and thinks it could help solve some of the growing e-waste problem. But that's exactly what researchers in Switzerland have done, creating a sponge-like material from whey proteins, a material that can soak up the milligrams of gold used in millions of electronic devices.
News of the work was reported by ETH Zurich (above Sweclocker), the institute that conducted the research in question. If you take a look inside a gaming PC, especially a full-featured desktop, you will see many large electronic circuit boards and many of the connections within them contain gold and other valuable metals.
However, it is not easy to extract these from old boards, which is why this type of research is ongoing.
To get the rare metals, the e-waste is usually placed in a large acid bath that dissolves the materials into a solution. Gold ions are floating in this liquid, but how do you get control of them? Enter stage left, Whey.
This is the liquid you see as the milk pours out and rises to the top while the solid curds fall. It is also a by-product of the cheese industry and because it contains lots of nice proteins, it can be used in many ways, such as food or dietary supplements. However, the research team had no interest in building mass.
They took the whey proteins and used them to form fibrillar amyloids; Think of these as groups of proteins in long, thin tendrils. They combine and, after drying, take the shape of a sponge, which is then placed in the acid solution with the gold ions. Once it is absorbed as much as possible, the sponge is removed and then heated to create a gold nugget.
The ETH Zurich report said 20 motherboards were used to test the method and together yielded a total of 450 milligrams of gold, worth about $30/£25, depending on the market. It is not 100% pure gold because although the sponge absorbs other metals, they were present in small enough quantities to rate the gold nugget at 22 carats.
Best of all, this method is not just a laboratory exercise: according to the researchers, it is truly cost-effective, with the total cost of materials and energy required being 50 times less than the value of the gold mined. This means there is a far greater chance of properly commercializing and scaling to the size needed to address the problem Huge amounts of electronic waste are generated every year.
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