Molecule Maker

Disposable diapers. That’s what inspired a groundbreaking toxic-chemical-capturing resin recently developed by UNC-Chapel Hill assistant professor of chemistry Frank Leibfarth.

After the 2016 discovery that perfluorinated alkylated substances, or PFAS, had contaminated North Carolina’s Cape Fear River Basin, representatives from the state-funded NC Policy Collaboratory visited the College of Arts and Sciences’ chemistry department looking for innovative solutions. Leibfarth’s colleague Marcey Waters suggested hydrogels, the super-swellable resins found in diapers. “Can’t you make a gel that soaks up PFAS?” she asked Leibfarth.

“I went back and read a lot of literature about how diapers work,” said Leibfarth. Hydrogels, it turns out, are made of polymers — substances made from strings of single molecules bonded together. 

Leibfarth and his team designed a fluorinated resin that, when ground into a powder and added to a water-filtration column, soaks up GenX — the trademarked PFAS made by Chemours at the company’s Fayetteville plant — the way diapers soak up water. GenX is prevalent in the Cape Fear River Basin, which provides drinking water for more than 1.5 million North Carolinians. Because GenX is negatively charged, Leibfarth’s team put positive charges on their resin, creating an extra-sticky electrostatic bond. In tests, Leibfarth’s resin removed more than 80% — or more than four times — the GenX than the best commercial technology.

The work is so promising that the UNC Institute for Convergent Science has partnered with the NC Policy Collaboratory to fund a demonstration phase of the research, with the hope of commercialization.

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