Old Milk Miracle – You Won’t Believe How This Ordinary Kitchen Ingredient Can Extract Gold from Your Old Electronics!
Discarded electronics, known as e-waste, often contain large amounts of gold and other heavy metals. There are various methods for recovering these valuable metals. However, many methods use harmful synthetic chemicals. However, a team of researchers at ETH Zurich in Switzerland has come up with a new and innovative way to extract gold from e-waste using a surprising ingredient – old milk.
The team, led by Raffaele Mezzenga, used whey protein – a byproduct of the cheesemaking industry – to create a low-density aerogel. This spongelike material is not only cheap to make, but it also has high porosity and surface area, making it an ideal candidate for extracting gold from e-waste solutions.
The process starts by placing whey protein into an acidic solution and heating it. This causes the proteins to unravel and form strands. The solution is freeze-dried next. This process creates a lightweight puck. The puck has high porosity. You can place them on the top of a flower, explains Mohammad Peydayesh, a chemical engineer involved in the research team.
To test the gel’s ability to adsorb gold from e-waste solutions containing other metals such as copper, lead, and nickel, the researchers found that it was able to remove 93% of the gold while only removing less than 10% of any other metal. In comparison, activated carbon – another commonly used adsorption method for recovering gold – only adsorbed about 60 mg per gram from an e-waste mixture.
What happens when this protein sponge is tested on actual e-waste? The team dissolved computer motherboards in aqua regia (a mix of nitric acid and hydrochloric acid) and found that each gram of aerogel was able to snatch 190 mg of gold. When the aerogel is burned, it releases the gold. This gold appears as a small piece of metal. It is about 91% pure. This purity level is equivalent to 21 to 22 carats.
It was really exciting to find this nugget in the ashes, recalls Peydayesh. Not only does this method present an improvement over traditional methods, but it also has a lower environmental impact. Activated carbon requires a lot of energy to create, making it less sustainable than using old milk.
The team is exploring other proteins from food waste. These could help recycle rare earth metals. We can simultaneously address the global waste of food and e-waste to produce something really precious, says Peydayesh.
So next time you pour out that old milk, think twice before throwing it away – it could hold more value than you think!
The value of the gold we recover is 50 times the value we invest to transform the protein into this sponge. – Raffaele Mezzenga
Source: GreekReporter.com
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