EES Seminar: The Role of Interfacial Processes in PFAS Transport and Remediation, Kurt Pennell, Brown U.

Details

Per- and polyfluoroalkyl substances (PFAS) represent a broad class of compounds consisting of a partially or fully fluorinated carbon chain with a hydrophilic head group. This unique chemical structure imparts surface-active properties, which can result in the accumulation of PFAS at air-water and oil-water interfaces. Experimental and modelling studies will be presented to explore how this phenomenon (a) influences PFAS transport and retention in the subsurface and (b) can be used to remove PFAS from water by foam fractionation. Batch experiments were completed to determine solid-phase sorption and accumulation at the air-water interface (AWI), while column studies were conducted at different water saturations. In the presence of PFOS, PFOA exhibited less retention than expected based on single-solute behavior, and effluent breakthrough curves showed chromatographic peaking. A mathematical model developed for simultaneous flow and transport of PFAS was able to capture these experimental observations. Foam fractionation studies were undertaken to identify co-surfactants that are capable of removing short-chain PFAS, which exhibit minimal accumulation at the air-water interface. A low-toxicity cationic surfactant derived from shea was able to rapidly remove PFAS from groundwater impacted by aqueous foam forming fluids (AFFF).

Dr. Kurt Pennell is the 250th Anniversary Professor of Engineering in the School of Engineering at Brown University. Previously, Dr. Pennell was Chair of the Department of Civil and Environmental Engineering at Tufts University, and the Bernard M. Gordon Senior Faculty Fellow in Environmental Engineering. Prior to moving to Tufts, Dr. Pennell was a Professor in the School of Civil and Environmental Engineering at the Georgia Institute of Technology. Dr. Pennell has published over 250 referred journal articles and book chapters, is a registered Professional Engineer (PE), a Board Certified Environmental Engineer (BCEE), a Fellow of the American Society of Civil Engineers (ASCE), and a Fellow of the Association of Environmental Engineering and Science Professors (AEESP).