Antibacterial effects of combined non-thermal plasma and photocatalytic treatment of culture media in the laminar flow mode

Physics of Fluids, Volume 33, Issue 4, April 2021. Acceleration of antibacterial properties is the targeted fashion of the recent part of our project by studying different techniques, on the culture media of E. coli., including the non-thermal effect using atmospheric pressure plasma jet (APPJ) and the non-thermal effects combined with the photocatalytic effects using APPJ coupled with a titanium dioxide TiO2 precursor. The electrical, non-thermal, and optical characteristics of the laminar and turbulent mode flow of a dry argon discharge afterglow using APPJ were vital in the study of the antibacterial properties, with the measured characteristics in the laminar mode flow as follows: frequency 25 kHz; applied voltage 11.2 kV; flow rate, 2.4 slm; power, 2.34 W; jet temperature, 340 K; jet length, 11.5 mm; jet width, 1.6 mm; energy, 96 mJ; and Reynolds number, 2819. Under all the measured characteristics of maximum laminar flow mode with the flow rate, 2.4 slm, the optical emission spectroscopy data of APPJ for dry Ar discharge and for wet argon (coupled with TiO2 precursor with the emerging jet) were measured. Survival curves of live microbes confirmed that as TiO2 precursor concentration increases in the range from 0 to 0.5 g l−1, the deactivation rate of E. coli increases due to the photocatalytic disinfection performance, because of the TiO2 precursor concentrations dosage enhances the effect of the incident plume of the non-thermal jet, leading to the generation of more active substances that can be absorbed by the cells causing acceleration of the sterilization efficiency.