Metal Oxide Particles as Atmospheric Nuclei: Exploring the Role of Metal Speciation in Heterogeneous Efflorescence and Ice Nucleation
Metal Oxide Particles as Atmospheric Nuclei: Exploring the Role of Metal Speciation in Heterogeneous Efflorescence and Ice Nucleation
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DOI：
10.1021/acsearthspacechem.2c00370
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发表时间：
2023-03-30
影响因子：
3.4
通讯作者：
Tolbert, Margaret A.
中科院分区：
文献类型：
--
作者：
Schiffman, Zachary R.;Fernanders, Marium S.;Tolbert, Margaret A.
矿物粉尘可以通过大气固体的成核作用间接影响气候，例如，通过混合相云中的非均匀成核冰或通过接触成核作用影响气溶胶和云的相态。矿物粉尘的单个成分的成核效果需要进一步研究。在这里，成核行为的金属氧化物纳米颗粒成分的大气矿物粉尘进行了研究。长工作距离光阱用于研究过渡金属氧化物对硫酸铵的接触和浸没成核，环境室用于探测金属氧化物颗粒上的沉积冰成核。以前的理论表明，冰成核和大气盐的非均质成核可以受到几个因素的影响，包括形态，晶格匹配和表面积。在这里，我们观察到的金属氧化物异质核的阳离子氧化态和它们的有效性之间的相关性，在接触风化模式和沉积冻结模式引起成核。与接触风化的活性相反，相同的金属氧化物颗粒浸入液滴中时，不会引起风化相对湿度的显著增加。这些实验表明，金属形态，可能作为阳离子电荷网站的结果，可能会发挥作用，在粒子表面引发的成核的有效性。
Mineral dust can indirectly impact climate by nucleation of atmospheric solids, for example, by heterogeneously nucleating ice in mixed-phase clouds or by impacting the phase of aerosols and clouds through contact nucleation. The effectiveness toward nucleation of individual components of mineral dust requires further study. Here, the nucleation behavior of metal oxide nanoparticle components of atmospheric mineral dust is investigated. A long-working-distance optical trap is used to study contact and immersion nucleation of ammonium sulfate by transition metal oxides, and an environmental chamber is used to probe depositional ice nucleation on metal oxide particles. Previous theory dictates that ice nucleation and heterogeneous nucleation of atmospheric salts can be impacted by several factors including morphology, lattice match, and surface area. Here, we observe a correlation between the cationic oxidation states of the metal oxide heterogeneous nuclei and their effectiveness in causing nucleation in both contact efflorescence mode and depositional freezing mode. In contrast to the activity of contact efflorescence, the same metal oxide particles did not cause a significant increase in efflorescence relative humidity when immersed in the droplet. These experiments suggest that metal speciation, possibly as a result of cationic charge sites, may play a role in the effectiveness of nucleation that is initiated at particle surfaces.