Unipolar charging of fine and ultra-fine particles using carbon fiber ionizers
Unipolar charging of fine and ultra-fine particles using carbon fiber ionizers
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DOI：
10.1080/02786820802339553
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发表时间：
2008-01-01
影响因子：
5.2
通讯作者：
Sioutas, Constantinos
中科院分区：
文献类型：
--
作者：
Han, Bangwoo;Kim, Hak-Joon;Sioutas, Constantinos
研制了一种简单、新颖的碳纤维离子发生器单极充电器，可对细颗粒物和超细颗粒物进行有效充电，且不产生臭氧。研究了粒径在20 ~ 200nm范围内的未带电、中和和单带电粒子在充电器中的穿透性。在不同的充电电压下，研究了细颗粒和超细颗粒的颗粒损耗和本征、出口和外在充电效率。无论颗粒初始充电状态如何，大于20 nm的颗粒在充电器中的穿透率接近100%。通过将施加在充电器上的电压从4.0 kV降低到2.3 kV，可以减少充电器中的颗粒损失。本征充电效率随外加电压成比例增加，而出口充电效率几乎与外加电压无关。因此，当施加电压较低（2.3 kV）时，约60%的20nm颗粒在此电压下充电，充电器的外在充电效率更高。在所有操作条件下产生的臭氧很少（小于4 ppb）或没有臭氧。可以得出结论，使用碳纤维电离器的新开发的单极充电器可以至少像目前可用的单极充电器一样有效地充电细颗粒和超细颗粒，但主要优点是可以忽略不计的臭氧产生，如果带电颗粒用于化学或生物分析，这是一个非常理想的功能。
A simple and novel unipolar charger using carbon fiber ionizers was developed to effectively charge fine and ultra-fine aerosol particles without the generation of ozone. The particle penetration in the charger was investigated for non-charged, neutralized, and singly charged particles in the size range of 20-200 nm. Particle loss and the intrinsic, exit and extrinsic charging efficiencies of fine and ultra-fine particles were also investigated for non-charged particles at different applied voltages to the charger. Particle penetrations in the charger were nearly 100% for particles larger than 20 nm, irrespective of the initial particle charging state. Particle losses in the charger could be decreased by decreasing the applied voltage to the charger from 4.0 kV to 2.3 kV. The intrinsic charging efficiencies were proportionally increased with the applied voltage, whereas the exit charging efficiencies were almost independent of the applied voltage. Therefore, the extrinsic charging efficiency of the charger becomes higher for the lower applied voltage (2.3 kV), at which about 60% of 20 nm particles were charged. Little (less than 4 ppb) to no ozone was generated under all operation conditions. It can be concluded that the newly developed unipolar charger using carbon fiber ionizers can charge fine and ultra-fine particles at least as effectively as currently available unipolar chargers, but with the major advantage of negligible ozone generation, a highly desirable feature if the charged particles are to be used for chemical or biological analysis.