Exposure of military personnel and civilians to per- and polyfluoroalkyl substances (PFAS) is a problem of increasing concern throughout the U.S. and represents a source of extreme potential liabilities for the USAF and other military organizations due to their past activities that have led to PFAS contamination at multiple military sites. PFAS are man-made chemicals that have been used in industrial and defense products for decades (e.g., Teflon®, Goretex®, Scotchguard®) and include items such as water-repellant clothing, stain-resistant fabrics and carpets, firefighting foams, and various defense products. Aqueous fire-fighting foam (AFFF) has been in widespread use for training exercises throughout the USAF for many decades on hundreds of Air Force Bases. PFAS leaches into soil, water and air, infecting the environments they encounter. PFAS do not breakdown via any natural processes (as the carbon-fluorine bond is one of the strongest in chemistry), so they remain in the environment and are ingested in humans and animals within the affected area through food and the water supply. PFAS have serious health impacts and can lead to harmful effects such as kidney and testicular cancer, thyroid disease and weakened childhood immunity, among many other serious medical conditions. Several methods are available commercially that treat PFAS-contaminated water, including granular activated carbon, specialized ion exchange media, foam fractionation, and reverse osmosis membranes. These methods are capable of purifying water to meet evolving regulations that require total PFAS concentrations below a few tens of nanograms per liter (ng/L), or parts-per-trillion (ppt) for the treated water. However, none of these methods destroy PFAS the PFAS remain in a more concentrated media, whether in aqueous solution or as an adsorbate on a solid material. While thermal methods are employed for final destruction of concentrated PFAS (these encompass high-temperature incineration and oxidative regeneration of activated carbon media), the reliability of thermal destruction of PFAS is still in question. Incomplete combustion of PFAS can lead to generation of fluorocarbon gases having extremely high greenhouse gas potential and can also potentially lead to distribution of PFAS downwind from incinerators. There is hence a strong need for an integrated process that concentrates PFAS from environmental sources and simultaneously fully destroys the PFAS.
