(398e) Interfacial and Foaming Properties of per- and Polyfluoroalkyl Substances (PFAS) Solutions

Per- and polyfluoroalkyl substances (PFAS) are a diverse group of partially or fully fluorinated manmade organic compounds, which have been applied into numerous applications, such as nonstick cookware and aqueous film-forming foams (AFFFs). While the PFAS offer significant benefits, their propensity to accumulate in living organisms and environment, particularly water bodies, raises substantial health concerns. Foam fractionation, a technique predominantly applied to surfactants and colloids, emerges as a potential strategy for PFAS removal from water sources. Despite its potential, the practical application of foam fractionation for PFAS removal is still evolving. The key to optimizing foam fractionation is to adjust the interfacial properties. Nevertheless, the relationship between the interfacial properties of PFAS and their foaming properties remains underexplored. In this study, we explore the surface tension and interfacial dilatational rheology of PFAS compounds with two distinct chain lengths. Moreover, the investigation into the foaming properties of PFAS shows that compounds with longer chain lengths, particularly those featuring sulfonic acid groups, are associated with improved foam production, enhanced foam stability, and increased liquid retention within the foam structures.