Ball-Milling Destroys PFAS While Recycling Valuable Fluorine

Researchers at the University of Oxford and Colorado State University have developed a new method for destroying per- and polyfluoroalkyl substances (PFAS) that can break down even the toughest PFAS fluoroplastics.  

The method, which aims to solve the problem of these extremely persistent “forever chemicals” building up in the environment, also preserves the fluorine content of these compounds, allowing them to be turned into useful, high-value fluorochemicals for future use.  

Published in Nature, the researchers believe that this technique could be an important piece of the puzzle in creating a more sustainable, circular fluorine economy. 

Improving PFAS remediation  

PFAS-containing products were produced in large quantities throughout the latter half of the 20th century, as the extreme chemical stability of PFAS made these compounds a useful inclusion in firefighting foams, food packaging and non-stick cookware. Today, PFAS are widely recognized as an environmental hazard; their chemical stability means that they also resist natural breakdown processes, meaning that these compounds build up in the environment and can have a negative impact on livestock, agricultural products and potentially human health upon extended exposure. 

To tackle this PFAS problem, researchers have created numerous ways to destroy these compounds. However, these aren’t without their drawbacks. 

“Although numerous methods have been developed for PFAS destruction, many methods are focused on functionalized classes of PFAS such as PFOA (perfluorooctanoic acid, a widely used surfactant) and lack generality,” Véronique Gouverneur FRS, professor of chemistry at the University of Oxford, told Technology Networks. “Incineration is a broadly accessible method, but the breakdown of PFAS compounds requires very high temperatures.” 

In the new Nature paper, a research team led by Gouverneur presents a new way to break down many types of PFAS which doesn’t just obliterate these compounds – it can also save and recycle their fluorine content, effectively transforming troublesome PFAS into a new source for high-value fluorochemicals.  

Their discovery of this new, simple PFAS destruction method came about while performing a separate set of experiments, during an investigation of different alkali metal fluoride-free (HF-free) synthesis techniques for producing fluorochemicals. 

“While performing a study on the HF-free mechanical activation of fluorspar (CaF₂), we found that the milling of fluorspar with potassium phosphate in a Teflon (PTFE)-sealed jar released more fluoride than anticipated, a result not seen when using rubber sealing ring,” Gouverneur recalled. “This experiment suggested that fluoride was released from PTFE and provided the inspiration to try mechanical activation for the destruction of PTFE and other PFAS classes.” 

Mechanochemistry is simple, reduces solvent use 

Ball-milling is a common griding technique that uses ball bearings in a rotating vessel to blend or grind materials down into very fine powders. However, chemists have also discovered that these kinds of mechanical forces can be used to drive chemical transformations – this is known as mechanochemistry.  

Gouverneur’s team found that ball-milling PFAS in the presence of potassium phosphate salts broke down the PFAS into smaller fluoride salts. The researchers then demonstrated that this recovered fluoride can be transformed into common fluorinating reagents that are used in industrial reactions. The method also allows for the phosphate salts to be recovered and reused, which the researchers note is an advantage due to the scarcity of phosphorous.  

“The new method has been successfully applied to a broad range of PFAS classes including polymeric PFAS (e.g. PTFE, PVDF, PFA), short-chain PFAS (e.g. PFOA, PFOS and fluorotelomers, as well as the electronics coolant liquid FC-70. The method also allows recovery of fluorine for re-use, as demonstrated with the generation of essential fluorochemicals,” Gouverneur said. “This was demonstrated with the synthesis of fluorochemicals used as common precursors for the preparation of pharmaceuticals, agrochemicals and battery electrolyte.” 

Gouverneur also highlights the rapidly depleting reserves of fluorspar – a fluorine-containing mineral that is used as a raw material in the production of steel, life-saving medicines, battery components and other fluorine products – as an important reason for developing methods that can enhance fluorine recovery.  

“[…] the production of fluorochemicals from waste PFAS reduces the amount of fluorochemicals that need to be produced from mined fluorspar, a mineral today classified as critical in many countries worldwide,” Gouverneur said.  

“Performing chemistry using mechanical conditions gives access to new reactivity with no need for solvents,” she added. “The method is also operationally simple.” 

The researchers hope that this method could mark the start of a shift away from thinking of PFAS as being “forever chemicals”, with the team now aiming to demonstrate the technique’s scalability.  

“One aim is to translate the technology from a laboratory scale to an industrial scale. More broadly, our goal is to render fluorine chemistry safe and circular for the benefit of humanity,” Gouverneur said. 

Reference: Yang L, Chen Z, Goult CA, Schlatzer T, Paton RS, Gouverneur V. Phosphate-enabled mechanochemical PFAS destruction for fluoride reuse. Nature. 2025. doi: 10.1038/s41586-025-08698-5 

About the interviewee: 

Dr. Véronique Gouverneur, FRS is the Waynflete Professor of Chemistry at the University of Oxford and a co-founder of FluoRok. 

Gouverneur secured a PhD in chemistry at the Université Catholique de Louvain  under the supervision of Professor Léon Ghosez. In 1992, she moved to a postdoctoral position with Professor Richard Lerner at the Scripps Research Institute. She accepted a position of maître de conférence at the University Louis Pasteur in Strasbourg ; during this period, she worked with Dr Charles Mioskowski and was associate member of the Institut de Science et d'Ingénierie Supramoléculaires led by Professor Jean-Marie Lehn.  

Gouverneur started her independent research career at the University of Oxford in 1998 in the Department of Chemistry and was promoted to professor of chemistry in 2008. Since her appointment in Oxford, she has held a tutorial fellowship at Merton College Oxford, where she teaches organic chemistry. Since 2022, she is the Waynflete Professor of Chemistry at Magdalen College. 

Her research aims at developing new approaches to address long-standing problems in the synthesis of fluorinated molecules including pharmaceutical drugs and probes for molecular imaging (positron emission tomography). To date, she has mentored more than 40 postdocs and supervised 55 PhD students (DPhil in Oxford) to completion. She has coordinated European ITN projects and received funding from numerous bodies, such as UKRI, ERC (ERC Advanced Grants 2019–2024 and 2024–2028) and EPSRC. She is the (co)author of > 230 peer-reviewed publications and 10 patents. 

Her research has been disseminated at numerous conferences and rewarded by multiple prizes and distinctions, including the 2015 ACS Award for Creative work in Fluorine Chemistry, the 2016 RSC Tilden Prize, the 2016 Tetrahedron Chair, the 2019 RSC Organic Stereochemistry Award, the 2019 Prelog Medal, the 2021 Henri Moissan Prize, the 2022 Arthur C. Cope Award, the 2022 EuChemS Female Organic Chemist of the Year Award, the 2024 Prous Institute - Overton and Meyer Award for New Technologies in Drug Discovery and the 2024 Davy Medal.  

Gouverneur has also been elected Member of the European Academy of Sciences (EURASC) in 2017, Fellow of the Royal Society in 2019 and International Honorary Member of the American Academy of Arts and Sciences in 2022.