Due to its unique physicochemical properties

plasma-activated water exhibits remarkable potentials for application in medical disinfection

agricultural cultivation

food processing

and other fields

thus plasma-activated water becomes a research hotspot both domestically and internationally. The traditional falling film dielectric barrier discharge (DBD) technique used for the preparation of activated water faces challenges such as poor discharge stability resulting from uneven water distribution and low efficiency in active species generation. We adopted the strategy of covering the falling film electrode with carbon cloth to enhance the uniformity of water distribution

thereby improving discharge stability and the efficiency of active species generation. We investigated the effects of carbon cloth covering the electrode on the DBD characteristics of the falling film

the generation of active species

and the inactivation effect on E. coli. The results indicate that the application of carbon cloth can improve the uniformity of water flow distribution within the cylindrical falling film. Under the same voltage conditions

the electrode covered with carbon cloth will significantly increase the number of filamentous discharge channels within the chamber

leading to a higher discharge density. Additionally

the concentrations of H2O2 and O3 in the plasma-activated waters prepared by using carbon cloth-covered electrodes are significantly elevated

while the concentration of NO3− remains relatively unchanged and the concentration of NO2− decreases. This phenomenon is attributed to the adsorption properties of the carbon cloth

which causes the active species to aggregate in its vicinity

thereby promoting secondary reactions among the short-lived active species and increasing the concentration of reactive oxygen species. In terms of sterilizing effect

E. coli can be further inactivated by 1 to 2 orders of magnitude with the carbon cloth compared to without it. This enhancement is attributed to the increased levels of H2O2 and O3 in the water

which improves the sterilizing performance of plasma-activated water (PAW). This study serves as a reference for advancing the preparation technology of plasma-activated water.