Electrochemical oxidation of PFAS: Unique challenges in landfill leachates
April 28, 2021
Per and polyfluorinated alkyl substances (PFAS) are toxic chemicals used in a wide variety of consumer goods and industrial processes. Their highly recalcitrant nature has led to their accumulation in the environment after disposal, resulting in contamination of many different water sources. Electrochemical oxidation (EO) is a promising strategy for destroying PFAS in a variety of impacted matrices. EO utilizes high current densities to oxidize the strong carbon-fluorine bonds of PFAS chains, ideally resulting in carbon dioxide and fluoride. This process has been successfully demonstrated on a fundamental level, however the application of EO in real world solutions presents new and unique challenges. Particularly for landfill leachates, variations in matrix composition between landfills and over time within the same landfill adds complexity to the design of a treatment protocol. The presence of PFAS precursor compounds at fluctuating concentrations makes predicting and optimizing treatment conditions very difficult, as solutions with higher precursor concentrations require longer treatment times and higher energy costs. Here, we present a summary of the efficacy of EO for leachates from three different landfills, and for leachate from the same landfill collected in different months, to highlight the implications of solution matrix on EO treatment performance.