Effect of Physicochemical Properties of Per- and Polyfluoroalkyl Substances (PFAS) on Their Foaming Behavior

Per- and polyfluoroalkyl substances (PFAS) represent a category of organic compounds, which have wide-ranging applications in various industries, including their use in aqueous film-forming foams (AFFFs), coatings, and surfactants, owing to their exceptional physicochemical properties. However, the accumulation of PFAS in living organisms and the environment raises concerns regarding their potential impact on human health. Water sources have been contaminated by PFAS, with reports indicating the transportation of PFAS through air-water interfaces. While foam fractionation shows promise as a method for removing surfactants and colloids from water sources, its current effectiveness in PFAS removal is limited. To improve the efficiency of foam fractionation for PFAS, it is essential to gain a profound understanding of PFAS physicochemical properties, for example, dynamic surface tension and dilatational rheological characteristics. Consequently, the present study discusses the adsorption at the air-water interface, interfacial dilatational moduli, and foaming behavior of both long-chain and short-chain PFAS. Additionally, we explore the correlation between Gibbs stability and PFAS foaming properties.