Colorado School of Mines
Raul Tenorio is a PhD student researcher in the Civil and Environmental Engineering department at Colorado School of Mines. His current research involves the study of per- and polyfluoroalkyl substances and their treatment using photochemical processes. He received a B.S. degree in Civil Engineering from the University of Texas at Austin and an M.S. degree from the University of Illinois at Urbana-Champaign in Environmental Engineering.
Remediation of Aqueous Film-Forming Foam (AFFF)-Impacted Groundwater by UV-Sulfite Treatment: Application for Treatment of Per- and Polyflurooalkyl Substances (PFASs) in Groundwater
Treatment and remediation of groundwater sites impacted by past use of aqueous film-forming foam (AFFF) at fire training areas has proven to be especially challenging due to recalcitrant and poorly sorbing nature of per- and polyfluoroalkyl substances (PFASs). Currently, remediation efforts with granular activated carbon (GAC) have proven to be costly when compared to treatment of other legacy contaminants due to the short adsorber bed lifetimes. It follows that effective and economical strategies for destruction of PFASs in groundwater are of great interest for site remediation efforts at the growing number of AFFF-impacted sites. This presentation describes recent efforts to advance UV photochemical treatment strategies using sulfite as a photosensitizer to generate strongly reducing hydrated electrons (eaq-; -2.9 V). Sulfite is advantageous as it is a low cost bulk chemical already used by the water industry and for food preservation, and produces mainly sulfate ions (present in natural waters) as a residual. We will describe results of experimental work from batch UV reactors simultaneously treating a wide diversity of PFAS structures present in AFFF mixtures, including perfluoroalkyl carboxylates and perfluoroalkyl sulfonates as well as polyfluorinated precursors (e.g., sulfonamides). Experiments track PFAS degradation, fluoride ion release, and sulfite decay simultaneously. Study of the treatment of complex AFFF mixtures is facilitated by use of high resolution liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS) analysis with a target screening list of >40 PFAS structures. Results for direct groundwater treatment will also be discussed.