Lasers turn trash to cash

One of the most well-known aims of the quasi-scientific field of alchemy was to transmute lead or other base metals into noble metals, such as gold. In a similar spirit of taking something cheap and abundant and transforming it into something rare and valuable, an international team of researchers from the U.S., Germany, France, Japan, and Norway used lasers to transform plastic into diamonds.

With all the talk of microplastics and the more than 60 million plastic bottles being thrown away in the U.S. every day, the advancement is welcome news, though it’s unlikely that people will be melting down their old action figures and turning them into a replica of the Hope Diamond anytime soon.

Courtesy of iStock.com/Chercvc and iStock.com/BlackJack3D.

The research from which this discovery stems was never meant to produce diamonds. It was initially focused on experimentally simulating the extreme conditions deep within planetary ice giants such as Uranus and Neptune. Ice giants are common in our galaxy. Their interiors are believed to be comprised mainly of a dense mixture of water, methane, and ammonia. The pressures deep within these celestial bodies can be intense, which causes their core elements to interact in strange and unknown ways to produce diamonds or superionic water.

The researchers’ key challenge involved designing an experimental setup that could simulate such planetary conditions. Other recent studies had led to evidence that combining laser shockwaves with x-ray techniques could mimic the states within the ice giants. The studies also happened to demonstrate evidence of the formation of diamonds from polystyrene.

The international team’s research, however, aimed to consider the presence of water and therefore figure oxygen into the mix. The oxygen atoms in supersonic water form a crystal lattice that is arranged in a diamond structure. The researchers used an x-ray free-electron laser to help simulate the conditions within the ice giants. They also replaced the polystyrene with polyethylene terephthalate (PET) — the plastic from which soda bottles are blow-molded. They found that the laser-driven shock compression of PET confirmed the ability to create nanodiamonds.

The team published their results in a paper in Science Advances.

According to the researchers, the observation of nanodiamonds tailored into various sizes, in the range of a few nanometers, could open a path toward an efficient and reliable source of the diamond material. Nanodiamonds have seen a steadily increasing number of applications in science, medicine, catalysis, and electronics. The researchers said state-of-the-art high-energy laser systems with hertz repetition rates could produce large amounts of the specifically tailored nanodiamonds from cheap PET.

Before taking out a short position on De Beers, it’s important to understand that the nanodiamonds produced this way are a far cry from the glittering stones found in a Neil Lane ring. Nanodiamonds might be found in a jewelry store, but in a polishing solution rather than in a display case.