Physicochemical Characteristics and Antimicrobial Efficacy of Plasma-Activated Water Produced by an Air-Operated Coaxial Dielectric Barrier Discharge Plasma

Abstract

In this study, Plasma-Activated Water (PAW) was synthesized using a coaxial Dielectric Barrier Discharge (DBD) reactor, benefiting from the elevated capacity of air-flow-assisted DBD discharges to enhance nitrogen-based species concentration. By manipulating operational parameters, including gas flow rate, activation time, and DI water volume, we achieved significant concentrations of reactive oxygen and nitrogen species (RONS). As a result, the PAW obtained displayed pronounced physicochemical attributes: a pH of 2.06, an ORP of 275 mV, conductivity of 3 mS/cm, and TDS of 1200 mg/L. A pivotal aspect of this research was the evaluation of the reactor’s efficiency, as indicated by metrics like the specific input energy and ozone efficiency yield. The antimicrobial potential of the PAW was also assessed against pathogenic microbes, with remarkable reductions in viability for both Staphylococcus aureus and Escherichia coli (99.99%) and a more moderate decrease for Candida albicans (37%). These findings underscore the capability of coaxial DBD reactors in crafting high-quality PAW with significant antimicrobial properties, necessitating further studies to validate its broad-spectrum and safe applications.

Physical and chemical characteristics of plasma-activated water generated by hybrid dielectric barrier discharge and gliding arc discharge

“…For gas flow control, an air rotameter (FLDA3215ST, Omega Engineering Inc., Stamford, USA) was employed. Further specifications of the DBD reactor geometry are detailed in [9,13,17].…”

“…It has been demonstrated that water treatment using plasma is a promising technique for designing the next generation for tooth-related diseases [5], bacterial inactivation [6], and treatment of cell cancer [7]. PAW production has been reported by different plasma sources such as pin-to-water plasma [8], dielectric barrier discharge (DBD) [9], and gliding arc plasma jet (GAPJ) [10].…”

“…Additionally, PAW often results in a notable decrease in pH levels, likely due to the increased concentrations of nitrite and nitrate, and changes in conductivity caused by the presence of these ions [11]. Despite the promising applications of PAW, studies show that the composition of PAW is sensitive to several parameters such as treatment time [12], type of gas [13], and plasma sources [8][9][10]. Due to the diversity of these parameters, controlling reactive species and pH for a given application is still a challenge in this area of study.…”