Enhancement of Plasma Jets and Plasma-Activated Water by Using Liquid Agitated Air-Bubble Diffuser

Abstract

The use of plasma-activated water (PAW) is receiving increasing attention as a sustainable technique for efficient biological and chemical decontamination. In the novel approach used in this study, a combination of a plasma-jet-activated gas bubble sparger and a liquid stirrer was used to maximize or effectively scale the efficiency of treatment with PAW. The plasma discharge and gas-liquid mass transfer can be enhanced synchronously. The dynamic behavior of the liquid vortex and bubble splitting significantly increase the gas-liquid mixing performance, and this enhances the mass transfer of plasma reactive species. Spatiotemporal propagation of the plasma jet is enhanced to a certain extent because of the negative pressure formed by stirrer rotation. This synergistic effect effectively increases the concentration of aqueous reactive oxygen and nitrogen species, and the oxidative capacity of PAW. This results in enhanced kinetic rate constants and a high energy yield in methyl orange (MO) degradation. The use of stirrer rotation to increase the reactive capacity of a plasma-bubble two-phase flow reactor could facilitate the development of alternative methods for degrading recalcitrant chemicals without the need for chemical dosage.