Scientists have invented a new way to destroy toxic substances known as “forever chemicals” that have become widespread in waterways around the world, presenting risks to human health and biodiversity, reports a recent study. The technique successfully broke down 95 percent of the pernicious chemicals, called perfluoroalkyl substances (PFAS), in just 45 minutes.
PFAS compounds are a complex group of chemicals that were first commercially manufactured in the 1940s, and quickly became ubiquitous in products such as cosmetics, cookware, textiles, among countless others.
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In recent decades, scientists have discovered that PFAS take an extremely long time to break down in water, a problem that has led to global contamination of groundwater, rainwater, drinking water, and other systems. Exposure to PFAS has been linked to ecological damage and a host of human health problems, including certain cancers, which has galvanized researchers across many fields to find new ways of removing these toxic chemicals from water systems.
Now, scientists at the University of California, Riverside (UCR), have presented ”a promising platform to treat PFAS-contaminated drinking water sources” that uses hydrogen and UV-light to obliterate some of these chemicals, according to a recent study published in the Journal of Hazardous Materials Letters.
“We are optimizing it by trying to make this technology versatile for a wide range of PFAS-contaminated source waters,” said study author Haizhou Liu, an associate professor of chemical and environmental engineering at UCR, in a statement. “The technology has shown very promising results in the destruction of PFAS in both drinking water and different types of industrial wastewater.”
The basic concept removes PFAS by infusing a contaminated source with hydrogen, which causes water to release electrons and other particles that can weaken the strong molecular bonds in PFAS. The UV light pulses supercharge these reactions, speeding up the time it takes for the toxic chemicals to fall apart into harmless components.
At this point, Liu and his colleagues have only tested out the method on two types of PFA—known as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)—in small volumes of tap water, measuring about two cups. However, the results were very promising: The effect of the hydrogen “increased the degradation of PFOA from 10% to 95%,” according to the study, “with 95% degradation achieved within 45-min treatment” at room temperature.
Though the technique is one of many emerging efforts to deal with PFAS pollution—a recent project used solvents to degrade a specific type of PFAS called PFCAs—it has a relatively low-energy footprint and does not produce harmful byproducts.
“The advantage of this technology is that it is very sustainable,” Liu said. He noted that hydrogen that is introduced into contaminated sources during the process becomes harmless water at the end of the reaction.
At this point, the system is still in an early phase of research, but the team hopes to eventually develop it into a commercially viable machine that could zap PFAS compounds out of large water tanks, and other sources.
“The hydrogen-based polarization technique may be readily applied to other water ionization systems to enhance reductive destruction of PFAS and other contaminants,” the researchers concluded in the study.
