Direct measurement of the viscosity of ternary aerosol mixtures
Direct measurement of the viscosity of ternary aerosol mixtures
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DOI：
10.1039/d2ea00160h
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发表时间：
2023-02-16
期刊：
影响因子：
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通讯作者：
Petters，Markus D.
中科院分区：
文献类型：
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作者：
Mahant，Sunandan;Iversen，Emil Mark;Petters，Markus D.
次生有机气溶胶占大气气溶胶的很大一部分。二次有机气溶胶的相态影响大气中的非均相和多相化学，从而影响气候。在以前的研究中，我们使用双串联差分迁移率分析仪技术来表征悬浮颗粒的温度和湿度依赖的粘度和玻璃化转变温度。然而，该技术需要高颗粒数浓度，是一个复杂的设置，是昂贵的，并且测量是耗时的。在这里，我们展示了一种新的简化和更具成本效益的方法来获得类似的数据。该技术用于测量由蔗糖/酒石酸/柠檬酸体系的二元和三元混合物组成的亚微米颗粒的粘度为~ 107 Pa s的温度。以蔗糖、酒石酸和柠檬酸作为大气中粘性有机气溶胶组分的代表。将数据子集与双串联差分迁移率分析仪方法的测量结果进行比较。结果表明两种方法吻合良好。使用Kasparoglu等人（2021,https://doi.org/10.5194/acp-21-1127-2021）中描述的参数相图模型的更新版本以及气溶胶无机-有机混合物官能团活度系数模型（aiomfacc - visc）粘度模块的预测，对相同的混合化学系统进行了建模。结果表明，适当的参数化混合规则适合于描述这些混合物。我们预计新技术将加速气溶胶相变在气溶胶研究中的发现。
Secondary organic aerosols contribute a large fraction to atmospheric aerosols. The phase states of secondary organic aerosols influence heterogeneous and multiphase chemistry in the atmosphere and thus climate. In previous studies we have used the dual tandem differential mobility analyzer technique to characterize the temperature- and humidity-dependent viscosity and glass transition temperature of suspended particles. However, the technique requires high particle number concentrations, is a complex setup, is expensive, and measurements are time consuming. Here we demonstrate a new simplified and more cost-effective method to obtain similar data. The technique was used to measure the temperature where the viscosity is ∼107 Pa s for submicron particles composed of binary and ternary mixtures of the sucrose/tartaric acid/citric acid system. Sucrose, tartaric acid and citric acid are taken as proxies for viscous organic aerosol components in the atmosphere. A subset of data were compared to measurements with the dual-tandem differential mobility analyzer method. Results show good agreement between the two techniques. The same mixed chemical systems were modeled using an updated version of the parametric phase diagram model described in Kasparoglu et al. (2021, https://doi.org/10.5194/acp-21-1127-2021) as well as the predictions with the viscosity module of the Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients model (AIOMFAC-VISC). Results show that appropriately parameterized mixing rules are suitable to describe these mixtures. We anticipate that the new technique will accelerate discovery of aerosol phase transitions in aerosol research.