‘Forever chemical’ discovery can aid drinking water cleanups |

Scientists at UC Riverside have made a discovery that could help water providers in the United States meet new federal standards that limit the concentration of “forever chemicals” in drinking water.

Scientists call them PFAS (poly- and perfluoroalkyl compounds), but they have been in use for thousands of years, from potato chip bags, to fire suppression foams. They are being phased out now because they leached in to groundwater and have been linked to cancers and other illnesses.

The U.S. Environmental Protection Agency imposed limits on water quality earlier this year that limit certain chemicals forever to 4 parts per trillion of tap water in the United States. This prompted water providers to seek PFAS cleanup methods.

Haizhou Liu is a professor at UCR who specializes in chemical and environmental engineering. His team discovered a process by which high levels of sodium, normally found as wastewater from water treatment facilities, can act as a catalyst that breaks down PFAS compounds, by cleaving stubbornly strong bonds between fluorine and carbon. Salt in wastewater normally impedes the removal of chemical pollutants. Environmental Science & Technology describes this solution to PFAS contamination.

This work is based on Liu’s discovery from 2022, that PFAS compounds could be destroyed by irradiating with short-wavelength UV light in a single-step treatment. The process does not require any additional chemicals and leaves no toxic residues. Both works are covered by patents.

Liu explained that they looked at PFASs with short carbon chains and also salty wastewater which has high concentrations of chloride and sulfur. The results showed that the saltiness in wastewater acts as an accelerator when it is exposed to UV light, making the process more efficient and faster.

Liu stated that the process is extremely effective at PFAS destruction, because the short wavelength ultraviolet light (which differs from the traditional UV light used to disinfect water) is not quenched in the wastewater by unwanted chemicals.

Liu stated that the technology not only destroys long-chained PFAS but also short-chained PFAS which are harder to remove by traditional separation techniques.

The breakthrough made by Liu’s team will benefit both municipal water companies and private water companies that plan or use “ion-exchange” technology in order to separate PFAS compounds out of drinking water that produces brine wastes containing PFAS contaminants.