In recent years, scientists have found PFAS (per- and polyfluoroalkyl substances) in just about every water source they’ve analyzed, from Arctic ice samples to tap water across the United States. These human-made chemicals—which are linked to immune system disturbances, some types of cancer, and reproductive issues such as high blood pressure in pregnant persons—are used in a wide variety of consumer products, including fast food containers, nonstick cookware, water-resistant clothing, and cosmetics. “They are used in almost every aspect of our daily lives,” said Bo Guo, an assistant professor in the Department of Hydrology and Atmospheric Sciences at the University of Arizona.
But even if people somehow managed to avoid PFAS-containing products, they could still be exposed, as PFAS leach into soil and groundwater from manufacturing facilities, landfills, and military sites. They “are super persistent under natural conditions,” Guo added.
As the nickname “forever chemicals” indicates, PFAS aren’t going to dissolve or dissipate in the environment without outside intervention. But clever chemists and innovative entrepreneurs are finding new ways to approach the pollution problem posed by PFAS.
First Step: PFAS Removal
Although strategies exist for filtering PFAS out of drinking water, they are far from perfect. One of the best-studied methods is activated carbon filtration, but these filters decline in effectiveness over time and create large volumes of PFAS-contaminated carbon sludge that’s difficult to safely dispose of.
Scientists like William Dichtel, a chemistry professor at Northwestern University in Evanston, Ill., are working on solutions for this difficult problem. In 2016, scientists in Dichtel’s lab created a polymer they have since named DEXSORB that’s derived from corn and can bind to different trace organic pollutants. Since then, they’ve been tweaking this material to better bind to PFAS to remove them more easily from the environment.
“One of the building blocks of the polymer is a molecule that’s shaped like a cup,” Dichtel explained. “There are trillions and trillions of these even in small samples of this polymer, and that cup is like a little docking site for many of these PFAS.” In water, PFAS will stick to the material and can be removed down to very low concentrations, he said. This polymer, and variations of it, are being developed for at-home filtration as well as municipal drinking water filtration, and Dichtel has cofounded a company called Cyclopure aimed at commercializing the products.
Dichtel said that future work in his lab will focus on making the polymer production process more cost-effective and on developing materials that target different types of PFAS. For…
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