Pharmaceutically Active Compound (PhAC) Degradation by Means of Cold Plasma Jet Treatment

The occurrence of emerging micropollutants of pharmaceutically active compounds (PhACs) in the environment poses a public health concern. Due to PhAC persistence and toxicity even at low concentrations, advanced oxidation processes (AOPs) have gained interest as effective treatment methods. In this context, the present study focuses on the application of a dielectric barrier discharge (DBD)-based plasma jet to Diclofenac (DCF) and Sulfamethoxazole (SMX) degradation in aqueous media. Plasma is sustained by continuous-wave sinusoidal high-voltage of audio frequencies, and negligible total harmonic distortion, in a helium–air mixture. The target pharmaceuticals are chosen based on anticipation of their occurrence due to rehabilitation center (DCF) and hospital (SMX) effluents in sewage systems. The degradation rates are determined by Liquid Chromatography Triple-Quadrupole Mass Spectroscopy (LC-MS/MS). Removal efficiency close to 100%, after 20 min of plasma treatment in the case of DCF at an initial concentration of 50 ppb, is achieved. The post-treatment action of the plasma-induced reactants on PhAC degradation over a day-scale period is studied. The results provide an insight into the dynamic degradation (kinetics) of both DCF and SMX, and they overall highlight the potentiality of the process under consideration for sewage remediation.