Densities of internally mixed organic-inorganic particles from mobility diameter measurements of aerodynamically classified aerosols
Densities of internally mixed organic-inorganic particles from mobility diameter measurements of aerodynamically classified aerosols
复制标题
DOI：
10.1080/02786826.2022.2062293
复制
发表时间：
2022-04
影响因子：
5.2
通讯作者：
Elinor T. Vokes;E. Lewis;Andrew L. Johnson;M. Cotterell
中科院分区：
文献类型：
--
作者：
Elinor T. Vokes;E. Lewis;Andrew L. Johnson;M. Cotterell
准确的颗粒密度知识对气溶胶科学的许多方面都是必不可少的。然而，对于内部混合的颗粒，特别是对于干燥的颗粒，密度往往表现得很差和不完全，以前的研究主要集中在潮解(含水)液滴上。相反，干燥的内部混合颗粒的密度通常是从质量组成测量与假设理想混合的预测模型相结合来推断的，此类模型的准确性无法估计。我们通过测量干颗粒的迁移率直径(使用Scanning Mobility颗粒仪，SMPS)来确定颗粒密度，这些干颗粒按空气动力学尺寸分类(使用气溶胶空气动力学分类器，AAC)，包括一系列包含已知比例的有机和无机物种的双组分有机-无机颗粒。我们研究了四种不同有机物质(水溶性黑松香染料、柠檬酸、聚乙二醇400和抗坏血酸)和三种不同无机物质(氯化钠、硫酸铵和硝酸钠)之间的所有混合排列。对于非挥发性颗粒，我们测量的颗粒密度的准确度和精密度分别为∼5%和∼1%。观察到颗粒密度与理想混合有很大的偏差(高达20%)。我们测试了对我们的系统的非理想混合的描述，方法是使用Redlich-Kister(RK)多项式以质量分数或摩尔分数来表示混合的体积变化，这两种方法的性能相似。图形摘要
Abstract Accurate knowledge of particle density is essential for many aspects of aerosol science. Yet, density is often characterized poorly and incompletely for internally mixed particles, particularly for dry particles, with previous studies focused primarily on deliquescent (aqueous) droplets. Instead, densities for dry internally mixed particles are often inferred from mass composition measurements in combination with predictive models assuming ideal mixing, with the accuracy of such models not estimated. We determined particle densities from mobility diameter measurements (using a Scanning Mobility Particle Sizer, SMPS) for dried particles classified by their aerodynamic size (using an Aerosol Aerodynamic Classifier, AAC) for a range of two-component organic-inorganic particles containing known proportions of organic and inorganic species. We examined all permutations of mixing between four different organic (water soluble nigrosin dye, citric acid, polyethylene glycol-400, and ascorbic acid) and three different inorganic (sodium chloride, ammonium sulfate, and sodium nitrate) species. The accuracy and precision in our measured particle densities were ∼5% and ∼1%, respectively, for nonvolatile particles. Substantial deviations in particle density from ideal mixing (up to 20%) were observed. We tested descriptions of the non-ideal mixing for our systems by representing the volume change of mixing using Redlich-Kister (RK) polynomials in terms of mass fraction or in terms of mole fraction, with both approaches performing similarly. Graphical Abstract