Hygroscopicity of nitrogen-containing organic carbon compounds: o -aminophenol and p -aminophenol
Hygroscopicity of nitrogen-containing organic carbon compounds: o -aminophenol and p -aminophenol
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含氮有机碳化合物的吸湿性：邻氨基苯酚和对氨基苯酚
DOI：
10.1039/d2em00163b
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Asa-Awuku, Akua A.
中科院分区：
文献类型：
--
作者：
Malek, Kotiba A.;Rastogi, Dewansh;Al-Abadleh, Hind A.;Asa-Awuku, Akua A.
含氮有机碳(NOC)是大气气溶胶的重要组成部分，受到大气科学界的广泛关注。虽然已经对它们的排放源、浓度和在大气中的二次形成进行了广泛的研究和进展，但对它们的吸水效率及其随后在气候、空气质量和能见度中的作用知之甚少。在这项研究中，我们分别使用吸湿性串联差示迁移率分析仪(H-TDMA)和云凝聚核计数器(CCNC)研究了两种难溶的芳香族NOCs：邻氨基苯酚(OAP)和对氨基苯酚(Pap)在过饱和和过饱和条件下的吸水性。我们的结果表明，OAP和PAP具有轻微的吸湿性，与各种所研究的有机气溶胶的吸湿性相当。测得OAP和PAP的过饱和单吸湿性参数(κCcn)分别为0.18±0.0 5和0.0 4±0.0 2，表明OAP与PAP具有相同的分子式，但其吸湿性比PAP强。观察到的吸湿性差异归因于官能团位置的差异、与气相水分子的相互作用以及所报道的NOC的整体水溶解度。在亚饱和条件下，OAP和Pap气溶胶均表现出与颗粒大小相关的吸水量。这两个物种在较小的干颗粒尺寸时都表现出生长，而在较大的干颗粒尺寸时都表现出收缩。在RH=85%时，随着粒径的增大，OAP和Pap的生长因子范围分别为1.60-0.74和1.53-0.74。由小颗粒和大颗粒的透射电子显微镜图像证实，生长和收缩的二分法是由于颗粒形态的差异。因此，必须考虑气溶胶的物理化学性质，才能正确预测大气中NOC气溶胶的液滴增长。
Nitrogen-containing Organic Carbon (NOC) is a major constituent of atmospheric aerosols and they have received significant attention in the atmospheric science community. While extensive research and advancements have been made regarding their emission sources, concentrations, and their secondary formation in the atmosphere, little is known about their water uptake efficiencies and their subsequent role in climate, air quality, and visibility. In this study, we investigated the water uptake of two sparingly soluble aromatic NOCs: o-aminophenol (oAP) and p-aminophenol (pAP) under subsaturated and supersaturated conditions using a Hygroscopicity Tandem Differential Mobility Analyzer (H-TDMA) and a Cloud Condensation Nuclei Counter (CCNC), respectively. Our results show that oAP and pAP are slightly hygroscopic with comparable hygroscopicities to various studied organic aerosols. The supersaturated single hygroscopicity parameter (κCCN) was measured and reported to be 0.18 ± 0.05 for oAP and 0.04 ± 0.02 for pAP, indicating that oAP is more hygroscopic than pAP despite them having the same molecular formulae. The observed disparity in hygroscopicity is attributed to the difference in functional group locations, interactions with gas phase water molecules, and the reported bulk water solubilities of the NOC. Under subsaturated conditions, both oAP and pAP aerosols showed size dependent water uptake. Both species demonstrated growth at smaller dry particle sizes, and shrinkage at larger dry particle sizes. The measured growth factor (Gf) range, at RH = 85%, for oAP was 1.60–0.74 and for pAP was 1.53–0.74 with increasing particle size. The growth and shrinkage dichotomy is attributed to morphological particle differences verified by TEM images of small and large particles. Subsequently, aerosol physicochemical properties must be considered to properly predict the droplet growth of NOC aerosols in the atmosphere.