Sodium nitrate particles: physical and chemical properties during hydration and dehydration, and implications for aged sea salt aerosols
Sodium nitrate particles: physical and chemical properties during hydration and dehydration, and implications for aged sea salt aerosols
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DOI：
10.1016/j.jaerosci.2004.02.003
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发表时间：
2004-07-01
影响因子：
4.5
通讯作者：
Finlayson-Pitts, BJ
中科院分区：
文献类型：
--
作者：
Hoffman, RC;Laskin, A;Finlayson-Pitts, BJ
本文介绍了NaNO_3粒子在不同相对湿度下的相态和行为的实验研究，这对阐明NaNO_3粒子在海洋区域化学和辐射特性中的作用具有重要意义。利用环境扫描电子显微镜（ESEM）和常规扫描电子显微镜结合X射线能谱分析（SEM/EDX）研究了水化过程中硝酸钠颗粒的变化。NaNO 3和NaCl的混合物，这是典型的部分加工海盐颗粒，也进行了研究。使用长路径FTIR进行了补充研究，以确定与NaNO 3气溶胶的水协会的程度，并进行比较，NaCl，MgCl 2，和NH 4 NO3，作为相对湿度的函数。这些技术的组合表明，NaNO 3颗粒存在不寻常的亚稳，无定形固体在低相对湿度，经历连续吸湿增长与相对湿度增加。虽然已经报道了这种现象的其他证据，但这是第一次使用环境扫描电镜进行直接观察。(C)2004爱思唯尔有限公司保留所有权利。
Experiments probing the phase and behavior of NaNO3 particles at different relative humidities, important for elucidating the role these particles play in the chemistry and radiative proper-ties of marine regions, are presented. Changes in NaNO3 particles during hydration were studied using environmental scanning electron microscopy (ESEM) and conventional SEM coupled with energy dispersive X-ray analysis (SEM/EDX). Mixtures of NaNO3 and NaCl, which are typical of partially processed sea salt particles, were also studied. Complementary studies using long path FTIR were carried out to determine the extent of water association with NaNO3 aerosols, and for comparison, NaCl, MgCl2, and NH4NO3, as a function of relative humidity. The combination of these techniques shows that NaNO3 particles exist as unusual metastable, amorphous solids at low relative humidity that undergo continuous hygroscopic growth with increasing relative humidity. While other evidence for this phenomenon has been reported, this is the first direct observation using ESEM. (C) 2004 Elsevier Ltd. All rights reserved.