ERASE-PFAS: Collaborative Research: Development of Quantitative Tools to Assess the Mechanisms and Full Poten-tial of UV-ARPs for the Treatment of PFASs in Water

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PFAS (per- and polyfluoroalkyl substances) are a group of man-made chemicals that have been widely used for many decades. PFAS contain numerous carbon-fluorine bonds that makes them extremely stable. This stability has led to them being called “forever chemicals.” The broad use of PFAS has resulted in widespread contamination of soil and water. This finding is of great concern, as PFAS exposure have been linked to serious health effects, such as cancer and birth defects. The urgency of this problem is made greater because PFAS are resistant to most conventional chemical and biological water treatment processes. One new technology that has shown promise for PFAS destruction in water is Advanced Reduction Processes (ARPs). ARPs produce electrons in water, which can react with PFAS to degrade halogenated compounds like PFAS. The goal of this project is to determine the potential of ARPs for remediating PFAS contaminated water. This goal will be achieved through research to: i) identify the important reactions occurring in the electron-based PFAS destruction process, and ii) develop quantitative tools for predicting PFAS degradation in ARP systems. Successful completion of this research holds promise to develop new technology to effectively treat PFAS contaminated water. Additional benefits to society result from increasing the Nation’s STEM workforce through the engagement and training of graduate and undergraduate students in research, as well as training of high school STEM teachers during summer training programs.Hydrated electrons are one of the strongest known reductants. Recent studies show that the hydrated electron is capable of reducing fluorine atoms in PFAS, including PFOA and PFOS, to non-toxic fluoride. However, a significant barrier preventing application of hydrated electrons for PFAS destruction is the lack of quantitative knowledge of hydrated electron-based processes in real-world waters. The goal of this project is to develop the quantitative data and tools necessary to assess the full potential of Ultraviolet-based Advanced Reduction Processes (UV-ARP) by addressing the underlying mechanistic limitations of hydrated electron-based PFAS degradation. This overall goal will be realized by focusing on three complementary objectives to: i) characterize the hydrated electron-based destruction efficiencies of parent PFAS and absolute fluoride yields, ii) develop the quantitative methods needed to predict PFAS degradation rates by UV-ARPs in real-world waters, and iii) use these quantitative tools to develop a “best case” UV-ARP treatment and compare this optimized system to other PFAS degradation technologies. These objectives will be accomplished using state-of-the-science time-resolved and steady-state radiolysis, combined with bench-scale UV-ARP experiments and kinetic modeling. The research will be integrated with education and outreach through high school STEM teacher training programs and engagement of undergraduate researchers at a primarily undergraduate institution. Additional benefits to society result from the sharing of research findings and recommendations for water treatment practitioners through partnership with the Orange County Water District, one of the largest full-scale advanced water treatment facilities in the Nation. Successful completion of this research will advance the fundamental science and engineering potential of ARPs for PFAS treatment in real-world waters.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.