Phosphate-enabled mechanochemical PFAS destruction for fluoride reuse

For decades, research into the severity and prevalence of Persistent Organic Pollutants (POPs) has been at the forefront of many institutional investigations across the globe. These pollutants are derived from a variety of household items and have been manufactured since as early as the 1930s and 40s. Products such as non-stick cookware, food packaging and textiles have at one time or another contained fluorine bonded chemicals. These now regrettable additives have the tendency to remain in the environment with strong resistance to degradation, resulting in catastrophic ecotoxicological build-up in aquifers and food chains.

Published this week in Nature (26/03/2025), University of Oxford chemistry researchers have developed a method to destroy fluorine-containing PFAS (sometimes labelled ‘forever chemicals’) while recovering their fluorine content for future use.

Poly- and perfluoroalkyl substances (PFAS) are a group of synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. The unique properties from these strong bonds also explains their resistance to degradation. PFAS were originally considered to be chemically inert. Early occupational studies revealed elevated levels of fluorochemicals in the blood of exposed industrial workers, but cited no ill health effects. The concentrations were well below toxic and carcinogenic levels cited in animal studies. However, the half-life of these chemicals is typically four to five years. Widespread environmental contamination has shown the propensity for accumulation in humans sufficiently to cause adverse health conditions.

A team of chemists from the University of Oxford and Colorado State University have demonstrated a method of destroying a wide variety of these fluorine-containing chemicals while also recovering their fluorine content for reuse in industrial processes.

This method works by reacting PFAS samples with potassium phosphate salts in the solid state. The reactants are ground together using ball bearings, which breaks down the long-lasting PFAS chemicals and allows the researchers to extract the fluorine content from the resulting product. In the study, the recovered fluoride was then used to generate common fluorinating reagents.

Recovery of fluoride in this way will “…contribute positively to a circular fluorine economy” Professor Véronique Gouverneur, Department of Chemistry, University of Oxford. This is particularly important given that fluorspar, the mineral from which all fluorochemicals are derived, is categorised as critical for many industrial processes by nations around the world. Furthermore, the phosphate used as an activator in the PFAS destruction process was recovered and reused, implying no detrimental impact on the phosphorus cycle.

The team’s method enables the mechanical destruction of all PFAS classes, including those commonly found in products such as non-stick coatings, electrical insulation and industrial tubing. This means that the fluorine content from everyday waste such as Teflon tape could be recovered and used to generate important fluorine-containing chemicals, including precursors to pharmaceutical and agrochemicals such as cholesterol-lowering statin medications (Lipitor), anti-seizure agents (Rufinamide) and herbicides (Triaziflam).

Like so many scientific discovers, the team’s initial observations were happened upon by circumstance. They noticed during an earlier experiment that the ball-milling jars containing sealing rings degraded the PFAS samples during the process. This resulted in higher fluoride yields than expected. They concluded that their process must be breaking down the PFAS in these sealing rings. This led them to wonder if the method may be able to break down and upcycle other examples of PFAS.

The researchers have now successfully demonstrated that the method does indeed have broad applicability across a wide range of PFAS. This tremendous breakthrough by the University of Oxford marks a defining moment in the combat against Persistent Organic Pollutants and may very well be the beginning of the end for “forever chemicals” in the environment and our food supply.