Synergistic Effect of Atmospheric-pressure Plasma and TiO2 Photocatalysis on Inactivation of Escherichia coli Cells in Aqueous Media

Abstract

Atmospheric-pressure plasma and TiO2 photocatalysis have been widely investigated separately for the management and reduction of microorganisms in aqueous solutions. In this paper, the two methods were combined in order to achieve a more profound understanding of their interactions in disinfection of water contaminated by Escherichia coli. Under water discharges carried out by microplasma jet arrays can result in a rapid inactivation of E. coli cells. The inactivation efficiency is largely dependent on the feed gases used, the plasma treatment time, and the discharge power. Compared to atmospheric-pressure N2, He and air microplasma arrays, O2 microplasma had the highest activity against E. coli cells in aqueous solution, and showed >99.9% bacterial inactivation efficiency within 4 min. Addition of TiO2 photocatalytic film to the plasma discharge reactor significantly enhanced the inactivation efficiency of the O2 microplasma system, decreasing the time required to achieve 99.9% killing of E. coli cells to 1 min. This may be attributed to the enhancement of ROS generation due to high catalytic activity and stability of the TiO2 photocatalyst in the combined plasma-TiO2 systems. Present work demonstrated the synergistic effect of the two agents, which can be correlated in order to maximize treatment efficiency.

Electron characterization in weakly ionized collisional plasmas: from principles to techniques

“…technology for a wide range of applications from environmental remediation, such as gas conversion [194,195] and pollutant destruction [196,197], to biological engineering [198,199] have shown impressive results. In this system, the heterogeneous interdependence between plasma and catalyst is quite complex, with plasma inducing physicochemical changes in the catalysts and vice versa, the catalyst modifying the electric field distribution and gaseous chemical composition [as presented in Figure 15(a)].…”

Cold Plasma‐Mediated Treatments for Shelf Life Extension of Fresh Produce: A Review of Recent Research Developments

“…In addition, the enhancement of plasma efficacy can also be achieved via synergistic action of plasma-mediated inactivation and biologically active silver nanomaterials, where, in addition to direct formation of oxidative species, the high catalytic activity and stability of plasma enhance chemical reactivity. Zhou et al (2016) explored the synergistic effect of atmospheric pressure plasma and TiO 2 photocatalysis on inactivation of E. coli cells in aqueous media, and results indicated that the inactivation efficiency of TiO 2 photocatalytic-assisted plasma treatment was significantly enhanced and the required time to achieve 99.9% killing of E. coli cells was also shortened by threefold.…”

“…Zhou et al. () explored the synergistic effect of atmospheric pressure plasma and TiO 2 photocatalysis on inactivation of E. coli cells in aqueous media, and results indicated that the inactivation efficiency of TiO 2 photocatalytic‐assisted plasma treatment was significantly enhanced and the required time to achieve 99.9% killing of E. coli cells was also shortened by threefold.…”

Contaminants of Emerging Concern Removal by High-Energy Oxidation-Reduction Processes: State of the Art

“…Krause tested an aluminum oxide-coated, rotating drum electrode, with the solution flowing on its outer surface as a thin film ( Figure 3A), while Magureanu used a dielectric barrier discharges (DBD) unit with falling film ( Figure 3B) [26,27]. Some recent developments in plasma technology include combination of atmospheric pressure plasma and photocatalysts (e.g., TiO 2 ) for microorganisms control in aqueous solutions [28]. After flowing through the 1st reactor, water is stored in a side tank.…”