大气压栅状介质阻挡放电等离子体空气消毒研究

Air Disinfection by Atmospheric Pressure Grating-like Dielectric Barrier Discharge Plasma

空气净化与消毒是控制呼吸道传染性疾病的有效途径。介质阻挡放电(dielectric barrier discharge,DBD)用于空气消毒具有高效、大面积放电、低风阻等优势,但目前对其空气消毒特性、消毒因子和消毒剂量的研究不足。文中介绍了清华大学电机系气体放电与等离子体研究团队近期关于栅状DBD等离子体空气消毒的研究进展。杀菌特性方面,重点研究了放电结构参量、湿度、微生物种类、电压类型等因素的影响,发现缩小间隙、增大电极尺寸、增加气流湿度均可提高杀菌效率和能量效率(Z值),相对湿度为60%时装置Z值可达1.68L/J;对MS2噬菌体气溶胶的单次通过净化效率可达99.5%~99.9%。杀菌因子方面,实验发现短寿命气相粒子是细菌气溶胶灭活的主要因子,长寿命粒子作用至多占总杀菌作用的30%。杀菌剂量方面,提出以比能量密度作为等离子体空气消毒的剂量参数,并基于湿空气放电的化学反应动力学模型,发现单粒子剂量与功率密度的线性关系,揭示了比能量密度作为剂量的机制。该研究可为介质阻挡放电空气消毒提供理论和工程应用支撑。

Air purification and disinfection are effective measures for the control of respiratory infectious diseases.Dielectric barrier discharge(DBD)is a promising method for air disinfection due to its high efficiency,large discharge area,and low airflow resistance;however,the research on its disinfection characteristics,factors,and dosage is rarely available in the literature.This paper provides a brief introduction of the recent research progress in air disinfection by grating-like DBD plasma from the Gas Discharge and Plasma Research Team in the Department of Electrical Engineering at Tsinghua University.In terms of disinfection characteristics,the effects of discharge structural parameters,humidity,microbial species,voltage type,and other factors was mainly investigated.It was found that narrowing the gap,increasing electrode size,and increasing airflow humidity could all improve both efficiency and Z-value.When the relative humidity(RH)was 60%,the Z-value could reach 1.68 L/J.The single-pass removal efficiency of MS2 bacteriophage aerosol could reach 99.5%~99.9%.In terms of bactericidal factors,experiments showed that gas-phase short-lived species were the major contributors to bacterial inactivation,with long-lived species accounting for at most 30%of the total bactericidal effect.In terms of disinfection dosage,specific energy density(SED)was proposed as the dose parameter for plasma-based air disinfection.Based on the chemical kinetic model of wet-air plasma discharge,a linear relationship between single-specie dose and power density was discovered,illustrating why SED could be served as the dose.This study can provide theoretical and engineering support for DBD-plasma-based air disinfection.