Investigation of metal catalysts for electrochemical reduction of GenX PFAS

• Jennafer Stevens, Chemistry, University of Maryland Baltimore County

• Dongxia Liu, Chemical & Biomolecular Engineering, University of Delaware
• Daniel Marshall, Chemical & Biomolecular Engineering, University of Delaware
• Izak Minnie, Chemical & Biomolecular Engineering, University of Delaware

Hexafluoropropylene oxide dimer acid (GenX) is a compound in a class of chemicals called per- and polyfluoroalkyl substances (PFAS), which are used in consumer and industrial products. GenX has been found in concentrations up to 4,000 ppt in the environment near manufacturing plants. PFAS exposure can cause cancers, reproductive issues, and suppression of the immune system in humans. To comply with regulations and limit these health impacts, methods need to be developed to capture and destroy PFAS found in the environment and drinking water. Previous research in PFAS degradation has shown high removal rates (up to 99%) but lower defluorination rates (46-71%) and have also formed dangerous byproducts. During this project, we look to use electrochemical reduction to defluorinate GenX more efficiently and with less harmful byproducts than previous methods. Linear sweep voltammetry was performed on silver, gold, copper, and palladium foil electrodes to determine the electrochemical reduction potential of GenX for each respective metal. We ran electrolysis for 24 hours at a constant -2.47 V vs Ag/AgCl potential to compare the kinetics and degree of defluorination. Palladium was the best performing electrode, showing 67% defluorination over the course of the electrolysis. The results of this study will help develop a method for electrochemical reduction of GenX chemicals and will improve our understanding of the mechanisms that contribute to electrochemical reduction of PFAS.