(471d) Controlling the Association of Pfas Surfactants in Aqueous Environments

Surface active per- and polyfluoroalkyl substances (PFAS) find niche applications because of their high chemical and thermal stability, their incompatibility with both water and hydrocarbons, and their unique ability to render surfaces non-stick. However, several widely used PFAS surfactants have been found extremely resistant to degradation, accumulate in the environment, and have long half-lives in humans, consequently causing great concern. In the context of sequestering PFAS surfactants from aqueous media, we research how such surfactants associate with (bind to) other molecules or particles/surfaces. We report here on ammonium perfluorooctanoate (PFOA) micelle formation and structure in aqueous solutions and micelle dissociation in the presence of various additives (alcohols, urea, electrolytes), probed with complementary experimental techniques (conductivity, surface tension, small-angle neutron scattering) and atomistic molecular dynamics simulations. Information on how the PFAS surfactant association in water can be modulated by various additives can inform the fate and transport of PFAS in the environment and the PFAS sequestration from aqueous media. Furthermore, ethanol is used in the regeneration of activated carbon that is commonly used for the adsorption of PFAS surfactants from aqueous media.