Cochran Richard E, Jayarathne Thilina, Stone Elizabeth A, Grassian Vicki H
Department of Chemistry and Biochemistry, University of California San Diego , La Jolla, California 92093, United States.
Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States.
J Phys Chem Lett. 2016 May 5;7(9):1692-6. doi: 10.1021/acs.jpclett.6b00489. Epub 2016 Apr 22.
Although theories have been developed that describe surface activity of organic molecules at the air-water interface, few studies have tested how surface activity impacts the selective transfer of molecules from solution phase into the aerosol phase during bubble bursting. The selective transfer of a series of organic compounds that differ in their solubility and surface activity from solution into the aerosol phase is quantified experimentally for the first time. Aerosol was produced from solutions containing salts and a series of linear carboxlyates (LCs) and dicarboxylates (LDCs) using a bubble bursting process. Surface activity of these molecules dominated the transport across the interface, with enrichment factors of the more surface-active C4-C8 LCs (55 ± 8) being greater than those of C4-C8 LDCs (5 ± 1). Trends in the estimated surface concentrations of LCs at the liquid-air interface agreed well with their relative concentrations in the aerosol phase. In addition, enrichment of LCs was followed by enrichment of calcium with respect to other inorganic cations and depletion of chloride and sulfate.
尽管已经有理论描述了有机分子在气-水界面的表面活性，但很少有研究测试表面活性如何影响气泡破裂过程中分子从溶液相选择性转移到气溶胶相。首次通过实验对一系列在溶解度和表面活性上存在差异的有机化合物从溶液到气溶胶相的选择性转移进行了量化。使用气泡破裂过程从含有盐以及一系列线性羧酸盐（LCs）和二羧酸盐（LDCs）的溶液中产生气溶胶。这些分子的表面活性主导了跨界面的传输，表面活性更高的C4 - C8 LCs的富集因子（55 ± 8）大于C4 - C8 LDCs的富集因子（5 ± 1）。在液-气界面处估计的LCs表面浓度趋势与其在气溶胶相中的相对浓度非常吻合。此外，LCs富集之后是钙相对于其他无机阳离子的富集以及氯离子和硫酸根离子的消耗。
