| The emergence of plasma jet technology provides a new method to achieve wide-scale,high-efficiency sterilization,and its advantages of high efficiency and no residue can make up for the shortcomings of traditional sterilization technology,which is of driving significance for the development of efficient sterilization in the biomedical field.Conventional plasma jet devices require the introduction of inert gas to lower the reaction conditions and generate plasma jets,which makes the experimental system huge and is not conducive to the wide application of plasma jets.In this paper,a needle-ring structure capable of generating plasma jets by ionizing air in an open environment at atmospheric pressure is designed and fabricated as follows:First,a needle-ring type arrayed self-excited plasma jet device with a jet unit spacing of 10 mm and a high-voltage electrode diameter of 1.1 mm is designed,and its physical properties such as current-voltage characteristics,spectral characteristics,and temperature characteristics are studied,and the feasibility of sterilization of the plasma jet generated by this device is investigated.The device is a combination of PCB and 3D printing,consisting of a PCB board,tungsten pins,and grounded electrodes with an overall size of about 50 ×50 × 38.5 mm3.The PCB board is perforated and the inner wall of the holes is covered with copper as the electrodes of the device.The experimental results of the jet morphology show that the length of the generated jet increases when the applied voltage is increased,up to 10 mm at an applied voltage of 11.5 k V.In addition,the reason for the sterilization capability of the plasma jet is analyzed from a theoretical point of view.Next,the active substances produced by the jet and the sterilization effect of the device were studied.Agar plates containing starch-potassium iodide were made using the color development reaction of potassium iodide(KI)to visualize the distribution of active substances.The experimental results showed that the range of active substance distribution increased with the increase of applied voltage at the same treatment time,and similarly,the range of active substance distribution increased with the increase of treatment time at the same applied voltage.The relationship between the distribution of active substance and sterilization of E.coli was investigated for two typical applied voltages(9.5 k V,11.5 k V).It was confirmed that the inactivation range of bacteria is closely related to the distribution of active substances.The sterilization range also increased with the increase of applied voltage and the increase of treatment time.When the applied voltage was 11.5 k V and the treatment time was 50 s,the sterilization area of the device was up to 703.36 mm2.Finally,the effect of four different diameters of high voltage electrodes of 0.8,0.9,1.1and 1.3 mm on the sterilization effect was studied.The experimental results showed that the jets produced by the four types of high-pressure electrodes with different diameters all had good uniformity,and the range of active material distribution and sterilization area were larger with the increase of applied voltage and longer treatment time.Among the four types of jet devices,the jet device with a high voltage electrode of 1.1 mm diameter had the largest sterilization area of 703.36 mm2.In addition,the matching percentage of the active substance distribution range and sterilization range was calculated.The comparison of the sterilization area and the matching percentage showed that among the four different diameters of high pressure electrodes,the jet device consisting of 1.1 mm diameter high pressure electrode had a better sterilization effect and higher sterilization efficiency. |
PDF Full Text Request