The Quantitative Analysis of Active Species Generated by Direct Current Plasma within Oxygen Bubbles

Abstract

In this research, concentrations of hydrogen peroxide and dissolved ozone generated by direct current plasma within oxygen bubbles in water were measured. The current magnitude and water conductivity were changed from 1 to 7mA, and from 1 to 100 μS/cm, respectively. The highest efficiency of hydrogen peroxide generation was 0.64g/kWh at 7mA with 100μS/cm solution. The concentration of dissolved ozone decreased with increasing the discharge current, and was almost zero when the current was higher than 5mA. Non-dimensional simulation revealed that the water vapor concentration in bubbles strongly affects the generation of active species. With a large current, the amount of water vaporized into the bubbles enlarged due to a large heat flux from plasma.