Per- and polyfluoroalkyl substances (PFAS) may no longer be the toxic “forever chemicals” that are so difficult to remove from water systems. Thanks to a development from University of California Riverside and Nanjing University, China, researchers, these persistent pollutants may now be tackled by adding iodide to an ultraviolet (UV) light/sulfite water treatment reactor.

The process destroys up to 90% of the strong carbon-fluorine bonds in PFAS in just a few hours, and theSource: Jinyong Liu et al./ Environ. Sci. Technol. 2022, 56, 6, 3699–3709 addition of iodide is reported to accelerate the reaction speed up to four times, resulting in reduced energy and chemical consumption. As documented in Environmental Science & Technology, addition of iodide to the UV/sulfite system to treat a particularly stubborn four-carbon PFAS molecule called perfluorobutane sulfonate accelerated the reaction and completely removed the compound within 24 hours.

The addition of iodide also enabled the system to destroy concentrated PFAS in brine solution, which is a practical challenge for groundwater remediation. Ion-exchange systems are used to clean the groundwater, but the PFAS chemicals captured in the resin need to be washed out and destroyed in a cost-effective way. “Not only does it [iodide] speed up the reaction but it also allows the treatment of a ten times higher concentrations of PFAS, even some very recalcitrant structures,” explained the researchers.