ERI: Unravel Phototransformation Mechanisms of Emerging Polyfluoroalkyl Surfactants in Water

Per- and polyfluoroalkyl substances (PFAS) are human-made chemicals found in many products. They persist in the environment and are potentially harmful to humans and the ecosystem. Polyfluoroalkyl surfactants are compounds that enter the environment through wastewater effluents and from sites that used aqueous film-forming foams. They are PFAS precursors that can transform into PFAS compounds in the environment. However, this transformation process is not fully understood. This project tests the hypothesis that the transformation relies on an interaction between dissolved black carbon (DBC), a natural component of organic matter in water, and sunlight. This interaction produces reactive compounds that can then transform polyfluoroalkyl surfactants into PFAS. The project will use a combination of experiments and modeling to test this hypothesis. The results of the research will contribute to better strategies for reducing PFAS contamination. The project will also support student training in STEM by bringing new environmental research into classrooms and public outreach events. The outcomes will advance knowledge and foster awareness of PFAS pollution and water quality issues.

This research project aims to elucidate the role of dissolved black carbon (DBC) in the photochemical transformation of emerging PFAS precursors under sunlight exposure. PFAS precursors undergo chemical changes in natural waters, potentially forming persistent perfluoroalkyl acids (PFAA). The central hypothesis of this project is that DBC can act as a sustainable source of photoproduced reactive intermediates (PPRI), thereby facilitating the transformation of PFAS precursors. This study will have three interrelated objectives: (1) characterization and selection of DBC types that promote sustainable PPRI generation, (2) experimental investigation of PPRI-mediated phototransformation mechanisms and rates of various PFAS precursors, and (3) development of a mathematical kinetic model to predict PFAS precursor degradation in aquatic environments. The research will integrate laboratory experiments and water microcosm studies to assess the efficiency and variability of PFAS precursor transformation under different environmental conditions. By leveraging analytical chemistry techniques, the study will quantify the reaction kinetics and identify transformation products, which will improve predictive capabilities for PFAS fate in natural waters. The outcomes of this work will provide critical insights into PFAS precursor removal processes, informing regulatory agencies and water treatment facilities on potential strategies for mitigating PFAS contamination.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Award Number: 2501881
Principal Investigator: Jianzhou He
Funds Obligated: $199,999
State: GA