Impact of Salinity and Temperature on Removal of PFAS Species from Water by Aeration in the Absence of Additional Surfactants: A Novel Application of Green Chemistry Using Adsorptive Bubble Fractionation

Aeration of water contaminated with per- and polyfluoroalkyl substances (PFASs) derived from the historical use of aqueous film-forming foams used in firefighting training and incident responses has been demonstrated to promote separation/concentration of PFAS by adsorptive bubble fractionation. This study examined the efficacy of changes in the environmental and process parameters, salinity, temperature, and aeration time on PFAS removal efficiency in the absence of additional amphiphilic substances, such as co-surfactants. The results demonstrate that the bubble fractionation process can operate effectively across a wide range of saline and temperature regimes and achieve high levels of overall PFAS removal (>95%). Removal by bubble fractionation of some short-chain PFAS species, characterized by lower air–water adsorption coefficients, was improved by both increased electrolyte (i.e., salt) and with decreased temperature in the treated water. Conversely, removal of total PFAS decreased slightly (to 93%) when processing higher temperature (37 °C) feedwater. The experiments demonstrate the viability of bubble fractionation of contaminated aqueous media as a primary PFAS removal step prior to PFAS concentration and subsequent destruction.