The acknowledged persistence of PFAS — per- and polyfluoroalkyl substances — in water systems has spurred the development of various adsorbents for capturing these forever chemicals. The focus has been on the use of fluorinated materials to harness PFAS, but these sorbents have the potential to release fluorinated compounds back into the environment. To remedy this problem, a reusable gel that seizes PFAS from water more effectively than many existing filters has been engineered by University of Florida researchers.

The “molecular Velcro” described in the journal Energy and Environmental Materials is a reusable gel relying on electrical charges to trap perfluorooctanoic acid (PFOA), one of the most abundant versions of PFAS in the environment. The gel allows PFOA molecules to bind throughout the material rather than only on its surface, improving its filtration capacity.

“A lot of the materials out there either don’t work well or have to rely on using fluorinated stuff to bind PFAS. We were able to develop these gel-type adsorbents that work well without having PFAS-like substances in the material itself,” explained the researchers.

The new nonfluorinated polymer sorbents were post-functionalized with Lewis base ligands via active ester “click” reactions. Poly(ethylene glycol) diacrylate copolymer networks incorporating strong Lewis bases such as piperidine, diethylamine, and piperazine in addition to hydrophobic dodecylacrylate co-monomers demonstrated PFOA removal efficiencies as high as 98%.

These adsorbents can also be efficiently regenerated using light alcohols such as methanol or isopropanol.