Using a few common and cheap reagents, scientists have successfully devised a method to get rid of two major classes of “forever chemicals.” Called PFAS or perfluoroalkyl chemicals, these are a group of chemicals known to stubbornly break down without much effort. These are manufactured and commonly used since the 1940s. Scientists have found that these chemicals can withstand fire forever and cannot even be diluted using water. Furthermore, when buried, these toxic chemicals mix into the surrounding soil and pose a threat to the environment while also affecting humans and animals.
A new method developed by researchers has proven effective at breaking down these chemicals, leaving behind only harmless end products. The chemical, PFAS, has been in use as a waterproofing and non-stick agent for more than 70 years. They are commonly used to make nonstick cookware, fire extinguishing foam, water-repellent clothing and waterproof cosmetics that resist oils and greases.
With such widespread use, PFAS has penetrated into consumer goods, into drinking water, and even into human blood. Although its health effects are not clear to researchers, exposure to PFAS has been shown to have developmental effects, decreased fertility and increased cholesterol levels in children, according to the researchers.
While experts have been successful in filtering PFAS out of water, destroying them has proved to be an enormous task. There are only a few options for doing this, one of which is the use of high temperature and pressure. However, this method is quite energy intensive and can result in the release of components into the air.
Recently, a group of researchers as part of a study discovered the compound’s ability to destroy it in another way. The team noticed a prominent group on the campus, which they called its Achilles heel. They targeted the group by heating PFAS in a common reagent called sodium hydroxide and noted that this process removed the head group and left behind the reactive tail.
“It triggered all these reactions, and started the fluorine atoms from these compounds to form fluoride, which is the safest form of fluorine. Although the carbon-fluorine bonds are super strong, the charge head group is the Achilles heel,” says Northwestern University’s William Dichtel said. The lead author of the study published in Dichtel is science,
The team used computer simulations and observed that only benign end products were left in the process they developed. The new technology can be used to successfully degrade 10 perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl ether carboxylic acids (PFECAs). These include one of its common substitutions called Genx, as well as perfluorooctanoic acid (PFOA), one of the most prominent PFAS.
Now, the team is aiming to test the new strategy for degrading other types of PFAS as well. “There are other classes that don’t have the same Achilles heel, but each will have its own weakness. If we can identify it, we know how to activate it to destroy it,” Dichtel said.