Do you want to destroy PFAS? But why stop there? Continue on to convert them into high value fluorochemicals, and recover and reuse the phosphate salts.
That’s what one new study claims it can do.
The authors reacted PFAS with potassium phosphate salts under solvent-free mechanochemical conditions — a mineralization process enabling fluorine recovery as KF (potassium fluoride) and K2PO3F (potassium fluorophosphate) for fluorination chemistry.
The phosphate salts can be recovered for reuse, implying no detrimental impact on the phosphorus cycle. Therefore, the authors say “PFASs are not only destructible but can now contribute to a sustainable circular fluorine economy.”
The study explains that to date, the PFAS degradation methods reported include chemical- and photochemical-initiated oxidation and reduction processes, mechanical, and base-assisted destruction, including low-temperature mineralization and incineration.
“With the knowledge that all fluorochemicals are produced from fluorite, a naturally occurring mineral currently categorized as critical by the European Union and other countries, the availability of a mild method that destroys PFASs with recovery of the fluorine content for upcycling would represent a paradigm shift in PFAS management,” the authors said.
The study discloses an “operationally simple solution entailing the reaction of various PFAS classes with potassium phosphate salts applying mechanical energy.” This process, according to the authors, enables “close to quantitative recovery of PFAS fluorine content as KF and K2PO3F.”
“Because we demonstrated that K2PO3F can be converted into KF or tetraalkylammonium fluorides, PFASs as diverse as polytetrafluoroethylene (PTFE; Teflon), polyvinylidene fluoride (PVDF), perfluorooctanoic acid (PFOA) or perfluorooctanesulfonic acid (PFOS) are not only destructible but can also serve as a viable fluorine source for upcycling into critically needed fluorochemicals for life and material sciences… This process enables the recovery of phosphate salts for reuse, which is an advantage in the era of phosphorus insecurity for fertilizer production.”
In summary, the authors explain that this study “presents a new approach to PFAS management, entailing a mineralization method coupled with the recovery of fluorine content for re-entry into the fluorochemical industry.”
“The best results, both in terms of PFAS destruction and isolation of fluorinating reagents, were obtained by ball milling PFASs with potassium phosphate salts.” The authors note “these salts can be recovered for reuse; therefore, minimal impact is imposed on the longevity of finite phosphate rock reserves and the phosphorus cycle.”
The study can be found here.