Study On Sterilization Efficiency Of Non-thermal Plasma (NTP) Air Cleaning Device

The paper briefly introduced the sources, characteristics and damages of indoor microbes, and summarized the current sterilizing technologies. Combined with the novel plasma technology, the non-thermal plasma (NTP) air cleaning device which has independent knowledge property right was adopted to kill air bacteria, and the needle-matrix-to-plate corona discharge was used to inactivate the PFV (para-influenza virus) in liquid membranes and aerosols. Principles of NTP sterilization and optimized conditional parameters were detected to improve the sterilization efficiency and confirm the inactivation efficiency. The scanning electron microscopy (SEM) were used to take photos of bacteria which was treated by the positive corona discharge, the morphological differences between the original bacteria and treated bacteria were observed and the microbe sterilization mechanism of positive corona discharge were discussed.The optimization experiments of 4 different input wind flow rate were carried out with the same discharge voltage of positive and negative corona discharge respectively, the results showed that the smaller wind treatment volume, i.e. smaller wind flow rate in the electric field has the higher the sterilization efficiency and the optimal wind treatment volume in the experiment is 57.8 m~3/h which is equal to the optimal flow rate in the electric field of 0.47 m/s. 4 sterilization experiments were carried out with different positive and negative applied voltage under the optimal flow rate mentioned above respectively. After 10 min sterilization by positive or negative corona discharge, the bacteria number indoor can fulfill the Hospital Disinfection and Sanitation Standard II(GB15928—1995) (less than 200 cfu/m~3). After 40 min sterilization, the best sterilization efficiency is more than 90%. With the same discharge mode and discharge voltage, the sterilization efficiency became better when treatment time become longer; with the same discharge mode and treatment time, the sterilization efficiency increases as the discharge voltage increases.