CAS: Elucidating Mechanisms of Perfluoroalkyl Substances Degradation in the Environment: A Coupled Computational Experimental Approach

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With support from the Environmental Chemical Sciences (ECS) Program in the Division of Chemistry at NSF, Shabham Vyas and his students at the Colorado School of Mines will study the reactivity of per- and polyfluoroalkyl substances (PFAS) in the environment. The project focuses on chemical reactions of PFAS with various reactive species, such as carbonate radicals, and the role metal ions play in this process. PFAS are among the most persistent anthropogenic chemicals that quietly proliferated throughout the world. The unique properties of PFAS, especially their chemical stability, lent them to diverse applications. However, research in the last two decades points to potential adverse effects of PFAS on the environment and in biological systems. This project will be carried out using cutting edge computer modeling and targeted experimentation with the overall objective of establishing methods to achieve complete breakdown of such environmental contaminants. This project will provide graduate and undergraduate students opportunities to participate in interdisciplinary research. Dr. Vyas also will participate in K-12 outreach programs to encourage students to pursue careers in STEM (science, technology, engineering and mathematics) fields. Kinetic and thermodynamic parameters for various chemical transformations, including electron transfer reactions, will be obtained using density functional theory and post-Hartree-Fock-based chemical computations. Concurrently, targeted experiments will be performed using techniques such as laser flash photolysis, time-dependent photolysis, electron paramagnetic resonance and mass spectrometry. The first objective of this work is to quantitatively measure the reactivity of PFAS with radical species and probe mechanisms of associated electron transfer reactions. The second objective will be to investigate the role of environmentally relevant transition metal ions in radical-mediated degradation of PFAS. The third objective of this project is to delineate the degradation mechanisms of PFAS and the impact of radicals and metal ions. Collectively, this research work will quantitatively establish the reactivity of PFAS and their degradation with the available reactive species in the environment. The ultimate goal would be to establish fundamental science that might one day lead to complete mineralization of PFAS.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.