Researchers at The Ohio State University found that ultrasound technology could be one way of breaking up the strong bonds that make "forever chemicals" so hard to get rid of.
Professor Linda Weavers, who researches ultrasound technology, said her team used sound waves to emit sound at an ultrasonic frequency so low it created tiny bubbles. She referred to the bubbles as tiny "combustion chambers." The bubbles reached temperatures of 10,000 Kelvin, which is so hot it cleaves, or tears, apart the strong flourine bond that held the molecules together in a process called ultrasonic degradation.
"So it's that high temperature that's...breaking the bonds, because these bonds are so strong. I need to add energy to break these bonds apart," Weavers said.
PFAS (polyflouroalkyl) substances are more commonly known as "forever chemicals" because the harmful substances are notorious for being hard to break down and dissipate at a molecular level. PFAS are toxic chemicals that come from the creation of a laundry list of everyday items such as cookware, cosmetics and food wrappers. And long-term exposure to even just a tiny amount of the man-made chemicals can pose health risks, like decreased fertility and some types of cancer.
The researchers focused their efforts on groundwater contaminated by the foam firefighters use to put out fires. The team used lab-made mixtures containing three different sized compounds of fluorotelomer sulfonates and their results showed that over a period of three hours, the smaller compounds degraded much faster than the larger ones. Other PFAS treatment methods weren't able to treat smaller PFAS as efficiently.
Weavers said this technique provides an advantage over other ways people have tried to rid groundwater of "forever chemicals," such as incinerating the water containing it or just filtering it out and sticking the chemicals in landfills without actually getting rid of it.
Weavers said despite this breakthrough, there is still a long way to go in eliminating "forever chemicals" from the environment.
"(PFAS) deserve that name. So, you know, even if we find a technology that breaks them down, they're going to be around for a long time, because they're in so many places," Weavers said.
Weavers said the next challenge is to find an economically sound way to use this technology in everyday life to slowly chip away at the amount of forever chemicals. She said this could be feasibly used for creating small, high-energy water filtration devices in everyday homes.
The research was published in The Journal of Physical Chemistry A.
