Understanding the Optimization and Scaling of a Plasma Reactor for the Decomposition of Per- and Polyfluoroalkyl Substances*

A plasma-water reactor featuring a packed-bed geometry of water streams exposed to non-equilibrium plasma has shown promise for the decomposition of per- and polyfluoroalkyl substances (PFAS) in water.  Several questions remain as to how various reactor operating conditions affect the decomposition efficiency.  This research explores the sensitivity of this efficiency to the reactor pulse frequency, power input, and the resulting plasma properties.  Waters contaminated with PFAS are treated using the plasma-water reactor at varying input powers, and efficiency performance metrics are evaluated using the calculated discharge power and the measured PFAS concentrations over the treatment time.  Optical emission spectroscopy is used to investigate how plasma parameters, such as gas temperature and plasma density, are related to the discharge power and the resulting PFAS decomposition efficiency.