正、负电晕对大肠杆菌气溶胶收集的影响

Positive and Negative Corona Discharge on Precipitation of E.coli-aerosols

为开发出新型有效的微生物气溶胶静电采样系统,考察了线筒式正、负电晕放电对大肠杆菌气溶胶带电荷情况的影响及收集作用。通过TK-3微生物气溶胶发生器产生大肠杆菌气溶胶,利用在线气溶胶分析装置ELPI(electrical low pressure impactor)研究了大肠杆菌气溶胶的带电荷情况。实验结果显示:大肠杆菌气溶胶空气动力学直径主要集中在0.8μm,不加电场时单个大肠杆菌气溶胶携带约9个正电荷;随着外加电场强度的改变,大肠杆菌微粒所带的电荷数也随之改变。单个大肠杆菌气溶胶在负电晕条件下最高可带26个负电荷,在正电晕条件下,最高可带14个正电荷。负电晕对微生物的收集作用要比正电晕高,最高可达到97%的收集效率,而正电晕最高可达到82%。

In order to develop a new type of static-charge bio-aerosol collectors, we investigated the influence of positive and negative corona discharge on the precipitation ofE.coli-aerosols. A TK-3 collision nebulizer was utilized to generate the E.coli-aerosols for testing, and the real-time number densities and the charges carried by the aerosols were measured using an ELPI （electrical low pressure impactor）. The results indicate that the E.coli-aerosols are mainly around 0.8 μm in aerodynamic diameter. E.coli-aerosol naturally carries about 9 positive elementary charges per cell, yet this amount changes with the applied electric field： per E.coli-aerosol cell carries as much as 26 negative elementary charges or 14 positive elementary charges in negative or positive corona discharges, respectively. The precipitation efficiency of negative corona discharge is higher than that of positive corona discharge. The maximum precipitation efficiencies of negative and positive discharges for E.eoli-aerosol are ab6ut 97% and 82%, respectively.