Titration of Aerosol pH through Droplet Coalescence
Titration of Aerosol pH through Droplet Coalescence
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DOI：
10.1021/acs.jpclett.9b00757
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发表时间：
2019-08-01
影响因子：
5.7
通讯作者：
Grassian, Vicki H.
中科院分区：
文献类型：
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作者：
Coddens, Ellen M.;Angle, Kyle J.;Grassian, Vicki H.
含水气溶胶以及云和雾滴的pH值对这些独特微环境中发生的化学反应具有重要影响。利用共轭酸/碱对推断pH值的变化，我们调查，第一次，在气溶胶pH值的变化后，聚结。特别是，我们表明，直径类似于8 μ m的单个含水气溶胶中的pH值可以通过气溶胶光镊中的液滴聚结来滴定。使用硫酸盐/硫酸氢盐和碳酸盐/碳酸氢盐作为模型系统，在引入含有强酸的较小气溶胶之前和之后确定捕获的气溶胶的pH。使用特定离子相互作用理论计算与较小的酸性气溶胶合并后的pH值变化。此外，我们表明，一个单独的气溶胶的pH值可以改变沿着一个相当宽的pH值范围内，铺平了道路，为未来的研究需要严格的pH值控制的水性气溶胶。
The pH of aqueous aerosols, as well as cloud and fog droplets, has an important influence on the chemistry that takes place within these unique microenvironments. Utilizing conjugate acid/base pairs to infer pH changes, we investigate, for the first time, changes in aerosol pH upon coalescence. In particular, we show that the pH within individual aqueous aerosols that are similar to 8 mu m in diameter can be titrated via droplet coalescence in an aerosol optical tweezer. Using sulfate/bisulfate and carbonate/bicarbonate as model systems, the pH of trapped aerosols is determined before and after introduction of smaller aerosols containing a strong acid. The pH change upon coalescence with the smaller, acidic aerosol is calculated using specific ion interaction theory. Furthermore, we show that the pH of an individual aerosol can be altered along a fairly wide range of pH values, paving the way for future studies requiring rigorous pH control of an aqueous aerosol.