The persistent nature of perfluorinated and polyfluorinated alkyl compounds (PFAS) in aquatic systems, soils and other environmental components has galvanized a quest for quick and economical contaminant removal methods. Despite plans to phase out their production, treating these toxic chemicals remains challenging as they decompose only at temperatures exceeding 400° C. Fortunately, researchers in Japan have developed a technique for breaking down these “forever chemicals” quickly and at room temperature.

The technique broke down 100% of perfluorooctanesulfonate (PFOS) after just eight hours of light exposure, recovering some useful components for reuse. The room-temperature defluorination method developed by researchers from Ritsumeikan University uses visible light to break down PFAS and other fluorinated polymers into fluorine ions.

The photocatalytic approach described in Angewandte Chemie International Edition focuses visible LED light onto cadmium sulfide (CdS) nanocrystals and copper-doped CdS nanocrystals with surface ligands of mercaptopropionic acid in a solution containing PFAS, fluorinated polymers and triethanolamine. Such treatment of the semiconductor nanocrystals yields electrons with a high reduction potential that decompose the strong carbon-fluorine bonds in PFAS molecules.

A room-temperature PFAS destruction approach has also been demonstrated by researchers from Clarkson University and the University of California Riverside. This decontamination process treats heavily contaminated water with ultra-violet light, sulfite and electrochemical oxidation. The method was demonstrated to achieve near-complete destruction of PFAS in water samples contaminated by PFAS-laden firefighting foams.

Researchers in Germany are advancing the use of a clay made of bentonite modified with organic substances as a possible PFAS filter. The bentonite is subjected to inorganic modification with titanium dioxide to obtain a pillared clay, and organic modification to obtain an organo-pillared-clay. The treated clay offers the possibility of increasing the adsorption capacity for PFAS from wastewater and exploits the catalytic mineralization of these toxins.

Similarly, an aqueous electrocatalytic process developed at the University of Rochester is based on the use of laser-made nickel-iron alloy-layered double hydroxide nanocatalysts has demonstrated complete defluorination of PFOS