Surfactant Optimization for PFAS Removal in Site Groundwater Using Colloidal Gas Aphrons ( CGAs )

ABSTRACT Colloidal gas aphrons (CGAs) have proven successful in separating both long‐ and short‐chain PFAS from water; however, little information is available on the impact of surfactants used for aphron generation. This study assesses the use of five cationic surfactant‐generated CGAs in batch experiments to remove PFAS from two site groundwaters. The results found that lauric arginate ethyl ester (LAE), a food‐grade surfactant used to generate CGAs, had the best performance, removing over 80% of PFAAs in a single stage. Removal rates were consistent between high‐ and low‐concentration waters, indicating its versatility. The addition of a second stage of treatment improved PFAS removal, particularly for short‐chain PFAS, as the first stage predominantly removed long‐chain PFAS due to their greater presence in the initial water. Higher salinity and saponins reduced the removal rates due to competitive sorption. Overall, the success of a food‐grade surfactant for CGA generation is significant in terms of water treatment.