Interfacial Properties of Per- and Polyfluoroalkyl Substances (PFAS) at Air-water Interface*

Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that are used in everyday products such as non-stick cookware, carpets, textiles, cleaning products, coatings, and firefighting foam. The PFAS have been detected almost everywhere in the U.S., particularly in water resources. More importantly, they are harmful and accumulate in our bodies. Therefore, PFAS contamination has become a major concern. PFAS have unique properties, for instance, high thermal and chemical stability and lowering the surface tension due to possessing a hydrophobic fluorinated tail and a hydrophilic head group in their structure. Therefore, they can accumulate at the air-water interface, which is regarded as the main retention source of PFAS transport in the environment. In the present work, we study the interfacial properties of PFAS with different chain lengths adsorbed at the air-water interface. Furthermore, we investigate the kinetics and equilibrium adsorption of PFAS along with the effect of salts and cosurfactants on PFAS adsorption at the air-water interface.