A discovery by UC Riverside scientists could assist water providers across the nation as they face new federal standards to limit “forever chemical” concentrations in drinking water.
Known by scientists as PFAS, or poly- and perfluoroalkyl substances, forever chemicals have been used in thousands of products, ranging from potato chip bags to fire suppressant foams. However, they are now being phased out because they have leached into groundwater supplies and are linked to certain cancers and other health maladies.
Earlier this year, the U.S. Environmental Protection Agency imposed water quality limits that restrict certain forever chemicals to only 4 parts per trillion in the nation’s tap water, spurring water providers to find PFAS cleanup solutions.
A UCR team led by Haizhou Liu, a professor of chemical and environmental engineering, discovered a chemical process that allows high levels of salt normally found in wastewater from water treatment plants to act as a catalyst that facilitates the breakup of PFAS compounds by cleaving the stubbornly strong fluorine-to-carbon bonds. Normally, salt in wastewater impedes the cleanup of chemical pollutants. This solution to PFAS pollution is detailed in the journal Environmental Science & Technology.
The work builds on Liu’s discovery in 2022 that PFAS compounds can be destroyed in a one-step treatment by irradiating water with short-wavelength ultraviolet light via tuning a process that does not require additional chemicals or leave behind toxic residuals. Both works are protected by patents.
“We were looking at PFAS with different carbon chains, short chains, and we also looked at salty wastewater that has a high concentration of chloride and sulfate,” Liu said. “The results show that the salinity in wastewater acts as a catalyst when receiving the UV light to make this process even more effective and much faster.”
Liu said the process extremely efficient at PFAS destruction because the short-wavelength ultraviolet light (which is distinct from traditional UV light used for water disinfection) is not quenched by undesirable chemicals in the wastewater.
“It not only destructs long-chain PFAS, but also short chains PFAS that are more difficult to get rid of by traditional separation technologies,” Liu said.
The breakthrough by Liu’s team is expected to benefit municipal and privately owned water providers that use or plan to use what is known as “ion exchange” technology to separate PFAS compounds from drinking water supplies that create brine waste containing PFAS pollutants.
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About UC Riverside
The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California’s diverse culture, UCR’s enrollment is more than 26,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual impact of more than $2.7 billion on the U.S. economy. To learn more, visit www.ucr.edu.