Effect of plasma jet diameter on the efficiency of reactive oxygen and nitrogen species generation in waterEffect of plasma jet diameter on the efficiency of reactive oxygen and nitrogen species generation in water Effect of plasma jet diameter on the efficiency of reactive oxygen and nitrogen species generation in water
The plasma jet generation of reactive oxygen and nitrogen species (RONS) in solution is important in biology, medicine, and disinfection. Studiesusing a wide variety of plasma jet devices have been carried out for this purpose, making it difficult to compare the performance betweendevices. In this study, we compared the efficiency of RONS generation in deionized (DI) water between 3.7-mm- and 800-μm-sized helium (He)plasma jets (hereafter mm-jet and μm-jet, respectively) at different treatment distances and times. The efficiency of RONS generation wasdetermined by considering the total amount of RONS generated in DI water with respect to the input energy and gas consumption. We found thatthe mm-jet generated 20% more RONS in the DI water than the μm-jet at the optimized distance. However, when the input power and He gasconsumption were taken into account, we discovered that the μm-jet was 5 times more efficient in generating RONS in the DI water. Under theparameters investigated in this study, the concentration of RONS continued to increase as a function of treatment time (up to 30 min). Howevertreatment distance had a marked effect on the efficiency of RONS generation: treatment distances of 25 and 30mm were optimal for the mm-jetand μm-jet, respectively. Our method of comparing the efficiency of RONS generation in solution between plasma jets could be used as areference protocol for the development of efficient plasma jet sources for use in medicine, biology, and agriculture.