Enhancing microorganism inactivation performance through optimization of plate-to-plate dielectric barrier discharge cold plasma reactors

Atmospheric pressure dielectric barrier discharge cold plasma (CP) is an effective method for inactivating microorganism contamination. However, improving CP inactivation efficiency as affected by CP reactor parameters still remains unstudied. In this study, the effects of discharge voltage, dielectric material and dielectric thickness of CP reactor on inactivation performance were investigated, and their influence mechanisms on plasma discharge were discussed. Results indicated that efficiency was improved using the reactor parameters of a high discharge voltage (17 kV) with a centre frequency (10 kHz) and a high dielectric constant (ceramic) with a small dielectric thickness (1 mm), resulting in higher electron number density and electric field strength, producing more reactive substances for enhancing microorganism inactivation. Under the above conditions, CP treatment for 4 min inactivated 99.6% of Salmonella typhimurium and 96.1% of Listeria monocytogenes. It is hoped that this work could guide the design of commercial CP systems.