Water-based particle size magnifier for wet sampling of aerosol particles
Water-based particle size magnifier for wet sampling of aerosol particles
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DOI：
10.1080/02786826.2021.1940828
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发表时间：
2021-06-13
影响因子：
5.2
通讯作者：
Seto, Takafumi
中科院分区：
文献类型：
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作者：
Ito, Erika;Tamadate, Tomoya;Seto, Takafumi
设计了一种水基粒度放大器（WPSM），并将其应用于气-液界面（ALI）上悬浮纳米颗粒的湿法采样。采用T形微混合器，通过冷气溶胶和含热水蒸汽的气体之间的瞬时湍流混合来使水蒸汽过饱和。通过改变WPSM的操作参数来评估氯化钠（10至40 nm）和硫酸锂（30至150 nm）的尺寸选择的测试颗粒的成核效率。发现超过80%的测试颗粒（>30 nm）成功地生长成大于2.3 μ m的液滴，2.3 μ m是冲击器的截止直径。水滴的冷凝生长也证实了使用光学粒度仪以及理论计算的实验。为了实现稳定的沉积在ALI，冷壁冷凝器用于排出多余的水蒸气从WPSM。由于在水面上的惯性沉积，空气中的颗粒物从空气中传输到液相通过ALI，和水的离子（Li+）被成功地检测到离子色谱（IC）。WPSM-IC系统的检测限低至0.33 μ g m（-3）-空气，相当于对数量浓度约为10，000个颗粒mL（-1）的30 nm颗粒进行10分钟采样。版权所有（c）2021美国气溶胶研究协会
A water-based particle size magnifier (WPSM) was designed and applied to the wet sampling of airborne nanoparticles at the air-liquid interface (ALI). A T-shaped micromixer was employed to supersaturate the water vapor by instantaneous turbulent mixing between a cold aerosol and hot water vapor-laden gas. The nucleation efficiency of the size-selected test particles of sodium chloride (10 to 40 nm) and lithium sulfate (30 to 150 nm) was evaluated by changing the operation parameters of the WPSM. It was found that over 80% of the test particles (>30 nm) successfully grew into droplets larger than 2.3 mu m, which is the cutoff diameter of the impactor. The condensational growth of the water droplets was also confirmed experimentally using an optical particle sizer as well as theoretical calculations. To realize stable deposition at the ALI, a cold wall condenser was employed for draining the excess water vapor from the WPSM. As a result of inertial deposition on the water surface, airborne particles were transported from air to the liquid phase through the ALI, and aqueous ions (Li+) were successfully detected by ion chromatography (IC). The detection limit of the WPSM-IC system was as low as 0.33 mu g m(-3)-air, which corresponded to the 10-minute sampling of 30-nm particles with a number concentration of approximately 10,000 particles mL(-1). Copyright (c) 2021 American Association for Aerosol Research