Thanks to a new breakthrough, “forever chemicals” may no longer be a problem for eternity. Chemists at Northwestern University have found a way to break down two major classes of PFAS chemicals into harmless by-products, according to a new study published in the journal Science.
Using powerful computational methods, the researchers found the “Achilles’ heel” of carboxylic acid–containing PFAS (per- and polyfluoroalkyl substances). Exploiting this weak spot, they were able to decompose the PFAS using low-cost reagents at a relatively low temperature.
PFAS are a large group of human-made chemicals found in hundreds of everyday things, from frying pans and food packaging to cosmetics and waterproof jackets. Despite being ubiquitous in the 21st century, they are linked to a host of consequences for human health, including reduced fertility, reduced fetal growth, changes in metabolism, increased chance of being overweight, and increased risk of some cancers.
Also known as “forever chemicals,” PFAS are notoriously tough to break down and can persist in the natural environment – and in our bodies – indefinitely. It’s estimated that PFAS can be found in the blood of 97 percent of Americans, despite recent efforts to reduce their use.
“PFAS has become a major societal problem,” William Dichtel, a chemist at Northwestern who led the stud, said in a statement.
“Even just a tiny, tiny amount of PFAS causes negative health effects, and it does not break down. We can’t just wait out this problem. We wanted to use chemistry to address this problem and create a solution that the world can use. It’s exciting because of how simple — yet unrecognized — our solution is,” he added.
This latest effort to battle PFAS takes advantage of a weakness in their otherwise sturdy chemical structure. PFAS are tricky to break down because they feature a long chain of carbon and fluorine bonds, which are the strongest bonds in organic chemistry. At the head of this chain, however, the molecule features a tip of weaker charged oxygen atoms.
By gently heating the PFAS along with dimethyl sulfoxide and sodium hydroxide, this weak head was “decapitated,” exposing its tail of carbon and fluorine bonds
“That triggered all these reactions, and it started spitting out fluorine atoms from these compounds to form fluoride, which is the safest form of fluorine,” Dichtel explained. “Although carbon-fluorine bonds are super strong, that charged head group is the Achilles’ heel.”
However, the war against forever chemicals is far from over. This low-temperature method was shown to break down 10 different PFAS, including some of the more prominent ones, but there are at least 11,900 other known PFAS compounds to tackle and it’s clear that this new process will only work on a select few.
Nevertheless, now the researchers have found a way to exploit this group’s weak spot, they’re optimistic that other vulnerabilities will soon reveal themselves.
“There are other classes that don’t have the same Achilles’ heel, but each one will have its own weakness. If we can identify it, then we know how to activate it to destroy it,” remarked Dichtel.