Portable Cold Plasma Sterilization Device Based on Dielectric Barrier Discharge and Its Characteristics

For handling the drawbacks of large volume, complex operation and high cost of circuit realization of existing cold plasma sterilization equipment, a portable cold plasma sterilization device incorporating the micro electric power supply technology with surface dielectric barrier discharge (SDBD) structure was proposed in this paper. The discharge characteristics, emission spectrum, active particles and O₃ concentration of plasma generator were studied, and the sterlization experiment was conducted with the sterilization device. The results show that the discharge filament around the SDBD linear electrode are uniform, the discharge power is no more than 5 W. The emission spectrum are mainly composed of N I, N₂ SPS, N₂⁺ FNS, O I and OH radical lines. The O₃ concentration within 3 mm from the discharge electrode reached 70 ppm, but O₃ concentration beyond 5 cm is very low. The sterilization device which moves with a homogeneously speed can completely kill Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus) in the petri dish (diameter 90 mm) within 15 s; The applied voltage and action distance have a significant effect on the sterilization effect, with the best applied voltage of 4.5 kV and action distance of 3 mm. This device has a lot of advantages, such as simple operation, high sterilization efficiency, low concentration of by-products (say, residual O₃, nitrogen oxide, etc.) and low noise.