Bulk, Surface, and Gas-Phase Limited Water Transport in Aerosol
Bulk, Surface, and Gas-Phase Limited Water Transport in Aerosol
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DOI：
10.1021/jp3086667
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发表时间：
2012-11-15
影响因子：
2.9
通讯作者：
Reid, Jonathan P.
中科院分区：
文献类型：
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作者：
Davies, James F.;Haddrell, Allen E.;Reid, Jonathan P.
使用电动平衡与光散射技术相结合，研究了溶质种类对水性气溶胶液滴的传质的影响。特别是，我们探索了缓慢的体相扩散和表面有机膜的形成对水蒸发的限制。将离子盐溶液（特别是氯化钠和硫酸铵）的蒸发测量与分析模型框架的预测进行比较，强调了与量化气体扩散传输相关的不确定性。报告了低溶解度有机酸对传质的影响，并与模型预测和之前的工作进行了比较。当考虑到关键热物理量的不确定性时，估计可以通过这种方法解决的蒸发系数的极限值。研究了硫酸镁和蔗糖液滴蒸发过程中分别形成的凝胶和玻璃态，缓慢的本体相扩散对蒸发速率的限制。最后，探讨了表面活性剂对蒸发的影响，可溶性表面活性剂（例如十二烷基硫酸钠）通过减慢表面层动力学而很少或没有导致蒸发延迟。
The influence of solute species on mass transfer to and from aqueous aerosol droplets is investigated using an electrodynamic balance coupled with light scattering techniques. In particular, we explore the limitations imposed on water evaporation by slow bulk phase diffusion and by the formation of surface organic films. Measurements of evaporation from ionic salt solutions, specifically sodium chloride and ammonium sulfate, are compared with predictions from an analytical model framework, highlighting the uncertainties associated with quantifying gas diffusional transport. The influence of low solubility organic acids on mass transfer is reported and compared to both model predictions and previous work. The limiting value of the evaporation coefficient that can be resolved by this approach, when uncertainties in key thermophysical quantities are accounted for, is estimated. The limitation of slow bulk phase diffusion on the evaporation rate is investigated for gel and glass states formed during the evaporation of magnesium sulfate and sucrose droplets, respectively. Finally, the effect of surfactants on evaporation has been probed, with soluble surfactants (such as sodium dodecyl sulfate) leading to little or no retardation of evaporation through slowing of surface layer kinetics.