Per- and poly-fluoroalkyl substances (PFAS) are a group of man-made chemicals widely used in industrial and consumer products, including fire-fighting foams, non-stick cookware, and food packaging. The presence of strong C–F bonds makes these chemicals thermally stable and allows them to be both hydrophobic and lipophobic.1-2 However, the presence of strong C–F bonds also makes them environmentally persistent and challenging to degrade. As such, these compounds are hazardous to all forms of life, including humans. Moreover, since these chemicals are man-made, biological enzymes have not evolved to degrade them naturally.2 Unfortunately, the majority of the drinking water resources in India and abroad are polluted with PFAS.3-4 Since conventional purification technologies are unable to separate the PFAS from water, drinking water is one of the primary sources through which PFAS enters the human body, where the PFAS intake should be limited to 0.02 ngL-1 for the widely-used PFAS like PFOS5 Although advanced oxidation and reduction processes are able to degrade these pollutants to some extent, complete degradation is rarely observed.6 Considering the hazardous nature of PFAS, it is crucial to invent novel PFAS degradation strategies to maintain a safe environment. In this thesis work, we would like to predict accurate thermochemical properties, such as bond dissociation energies (BDEs),7 and enthalpy of the formation of PFAS to identify the weak bonds in PFAS to design feasible degradation pathways. Additionally, we are investigating plasmon-induced degradation methods for PFAS, where metal nanoparticles are used as the source of plasmons as well as reducing agents. Such methods provide alternative paths to degrade molecules efficiently using solar light.8

References
(1) Kannan, K. Perfluoroalkyl and Polyfluoroalkyl Substances: Current and Future Perspectives. Environ. Chem. 2011, 8 (4), 333.
(2) Rahman, M. F.; Peldszus, S.; Anderson, W. B. Behaviour and Fate of Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs) in Drinking Water Treatment: A Review. Water Res. 2014, 50, 318–340.
(3) Sharma, B. M.; Bharat, G. K.; Tayal, S.; Larssen, T.; Becanova, J.; Karaskova, P.; Whitehead, P. G.; Futter, M. N.; Butterfield, D.; Nizzetto, L. Perfluoroalkyl Substances (PFAS) in River and Ground/drinking Water of the Ganges River Basin: Emissions and Implications for Human Exposure. Environ. Pollut. 2016, 208 (Pt B), 704–713.
(4) Smalling, K. L.; Romanok, K. M.; Bradley, P. M.; Morriss, M. C.; Gray, J. L.; Kanagy, L. K.; Gordon, S. E.; Williams, B. M.; Breitmeyer, S. E.; Jones, D. K.; DeCicco, L. A.; Eagles-Smith, C. A.; Wagner, T. Per- and Polyfluoroalkyl Substances (PFAS) in United States Tapwater: Comparison of Underserved Private-Well and Public-Supply Exposures and Associated Health Implications. Environ. Int. 2023, 178, 108033.
(5) Liu, F.; Guan, X.; Xiao, F. Photodegradation of per- and Polyfluoroalkyl Substances in Water: A Review of Fundamentals and Applications. J. Hazard. Mater. 2022, 439, 129580.
(6) Wen, Y.; Renteria-Gomez, A.; Day, G. S.; Smith, M. F.; Yan, T.-H.; Ozdemir, R. O. K.; Gutierrez, O.; Sharma, V. K.; Ma, X.; Zhou, H.-C. Integrated Photocatalytic Reduction and Oxidation of Perfluorooctanoic Acid by Metal-Organic Frameworks: Key Insights into the Degradation Mechanisms. J. Am. Chem. Soc. 2022, 144 (26), 11840–11850.
(7) Nayak, S. K.; Yamijala, S. S. R. K. C. Computing Accurate Bond Dissociation Energies of Emerging per- and Polyfluoroalkyl Substances: Achieving Chemical Accuracy Using Connectivity-Based Hierarchy Schemes. J. Hazard. Mater. 2024, 468, 133804.
(8) Li, T. E.; Hammes-Schiffer, S. Nuclear-Electronic Orbital Quantum Dynamics of Plasmon-Driven H Photodissociation. J. Am. Chem. Soc. 2023, 145 (33), 18210–18214.