Implementing water recirculation in a novel portable plasma-activated water reactor enhances antimicrobial effect against Escherichia coli

Surface DBD in moist air for nitrogen fixation: a comparative study of pulsed versus amplitude-modulated AC powered discharge

“…This resulted in a slight yield increase in NO 2 − and NO 3 − concentration for an AC power source (figures 11(a) and (b)) and equalization of NO 2 − /NO 3 − yields in the case of a pulse (figures 11(c) and (d)). The production yields are also generally higher for higher water flows, as the mass transfer of reactive species is enhanced due to continuous mixing and renewal of the water interface [36]. The highest achieved values of NO 2 − and NO 3 − concentrations, and yields are summarized in table 3 with conditions under which they have been achieved.…”

“…Concerning PAW properties, from the viewpoint of nitrogen formation, pulse power produced a better-balanced ratio of NO 2 − /NO 3 − although the absolute formation of reactive nitrogen species (RNS) was higher with AC power source accompanied with higher acidity and conductivity of produced PAW. Better selectivity of NO 3 − production, as achieved in AC-powered discharge, is believed to be connected to higher treatment/operation times and availability of oxygen in working gas [29,30,36]. This could be translated to AC vs pulse comparison through a higher residence time of molecules in AC discharge which leads to more opportunities to oxidize NO x molecules to a higher oxidation state thus resulting in a higher NO subsequent dissolution into the PAW, which was more significant in the case of lower flow rates of water through the plasma reactor and accompanied by a higher drop of pH of PAW in that case (figure 10).…”

“…It can be assumed that the fixation efficiency in this geometry represents a lower bound compared to alternative DBD geometries in which partial or full plasma-liquid contact occurs. A conceptually similar design (SDBD flowthrough reactor) has been recently investigated by Agus et al [36] for the antibacterial efficacy of its PAW, while Roy et al [29,30] employed a VDBD setup with discharge filaments perpendicular to the water surface to study selectivity and energy efficiency of NO 3 − synthesis. This paper is organized as follows.…”