Recycling technology has hit a new milestone thanks to a recent breakthrough by western scientists. Researchers in Germany and California have found a way to convert plastic into extremely tiny diamonds called nanodiamonds.
It started in 2017 when the same scientists used polystyrene (Styrofoam) to produce diamonds. 5 years later, these scientists are back at it again, but this time using polyethylene terephthalate (PET) plastics, which are commonly found in bottles, clothing, carpets, and more. The study was published on Friday in Science Advances.
The discovery paves the way for a new form of recycling, which is based on some exoplanets in our universe that rain diamonds, namely Uranus and Neptune. These planets have extreme weather conditions that result in diamond rainfall, and scientists replicated these conditions to get the same results.
Polystyrene has the same form of hydrogen and carbon found on Uranus and Neptune. They exposed the material to a high-powered X-ray laser, which rapidly heated the polystyrene to 4700 Celsius and then compressed it by 150 gigapascals to replicate the conditions found in the interior of icy planets.
The scientists managed to create nanodiamonds with two quick hits from the laser, but they realized that one key ingredient was missing – Oxygen. That is where PET comes in, which has a good balance of carbon, hydrogen, and oxygen.
The scientists put PET through the same tests, but also used a technique called small angle X-ray diffraction to see how quickly and how large the diamonds grow. The research team found that the presence of oxygen was enhancing diamond formation, making them grow larger under higher pressure with more time.
They were also able to make a lot more tiny diamonds with a single hit from the X-ray laser, which had a few micrograms of total weight. However, Dominik Kraus, a scientist at the German research laboratory, said that this isn’t enough as they will need to produce at least a few milligrams for it to be practical. It could be scaled up even further in the future to allow for proper everyday recycling.
Kraus said:
If industrial scaling of the formation process indeed works as discussed above, and nanodiamonds will be required in very large quantitates for certain processes, e.g., catalysis for light-induced CO2 reduction reactions helping to reduce global warming, this may indeed become a potential way to recycle large amounts of PET.
