Organophosphorus toxic compounds degradation in aqueous solutions using single filament dielectric barrier discharge plasma jet source

In this paper, we report the degradation of four organophosphorus toxic compounds (Chlorpyrifos, Dimethoate, Parathion, and Dimethyl methylphosphonate) from aqueous solutions with different concentrations (5, 10, and 20 ppm), using an atmospheric pressure DBD (Dielectric Barrier Discharge) plasma source. The discharges were performed in Ar, Ar/N2, Ar/air, and Ar/O2 mixtures, at 100 W, for different treatment times. In order to investigate the degradation process, reactive gas species transferred in liquid were monitored by Optical Emission Spectroscopy (OES), and the liquid pH, conductivity, nitrate, and dissolved oxygen concentrations were measurements. The degradation products were determined by gas chromatography-mass spectrometry (GC-MS) investigation. The highest degradation percentages for the 20 ppm solutions were 99.72% for Parathion, 93.76% for Chlorpyrifos, and 85.55% for Dimethyl methylphosphonate, after 20 min of Ar/N2 plasma treatments, and 74.26% for Dimethoate, after 20 min of Ar/compressed air plasma treatment.