Influence of the electric discharge and the power supply on the aqueous solution interface parameters

Abstract

Laboratory electrical discharges that produce non-thermal plasma are used more and more for microbiological decontamination, surface treatment and depollution by the means of decomposing some complex molecules or in the field of modern medicine. Each application requires a power supply particularly adapted to the plasma reactor type used. If the first applications of these discharges were designed mostly for reactor types with high volume discharge capabilities, and the power supplies were simple and robust generating high power using industrial frequencies, in time the reactors decreased significantly in size and the power supplies used were working on higher frequencies. This trend was adopted on one hand out of the need for energy optimization of the power supplies used, and on the other hand for obtaining a better homogeneity of the treatment. This paper aims to provide a comparison of few AC and pulsed power supplies, working at different frequencies, with respect to the electrical parameters, from the point of view of active species production. The measured electrical parameters of the electrical discharges are the power and the specific energy. Also the results obtained for treatment of distilled water using three types of plasma reactors (classic GlidArc, Mini-torch plasma and Gliding Spark) will be shown. The analysis focus on the modification of pH of the distilled water in time after the plasma treatment.