Chingin Konstantin, Yan Runhan, Zhong Dacai, Chen Huanwen
Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang 330013, China.
ACS Omega. 2018 Aug 7;3(8):8709-8717. doi: 10.1021/acsomega.8b01157. eCollection 2018 Aug 31.
The pronounced enrichment of surface-active compounds in the aerosols produced by bubble bursting plays a central role in the chemical transfer from the ocean into the atmosphere and has an important impact on the global Earth's climate. However, the mechanism of chemical enrichment in bursting bubble aerosols remains poorly understood and controversial due to the high complexity and diversity of experimental behaviors. Contrary to the common belief, here we show that the major share of surfactants in the jet droplets produced by individually bursting bubbles at a calm solution surface is released directly from the bubble surface rather than from the solution surface or subsurface microlayer. We reveal that surfactants are accumulated at the surface of a rising bubble in solution following three successive stages with strongly distinct adsorption profiles: linear kinetic, mixed kinetic, and equilibrium. The magnitude of surfactant enrichment in the aerosol is directly determined by which adsorption mode is in control by the moment of the bubble bursting at solution surface. Our mechanistic description explains the diversity of experimental observations regarding the surfactant enrichment in aerosol droplets and lays the ground for understanding the more complex behaviors associated with collective effects at the solution surface (e.g., breaking waves).
气泡破裂产生的气溶胶中表面活性化合物的显著富集在从海洋到大气的化学转移中起着核心作用，并对全球地球气候产生重要影响。然而，由于实验行为的高度复杂性和多样性，破裂气泡气溶胶中化学富集的机制仍知之甚少且存在争议。与普遍看法相反，我们在此表明，在平静溶液表面单个气泡破裂产生的射流液滴中，表面活性剂的主要部分是直接从气泡表面释放出来的，而不是从溶液表面或次表面微层释放出来的。我们揭示，表面活性剂在溶液中上升气泡的表面按照三个连续阶段积累，具有截然不同的吸附曲线：线性动力学、混合动力学和平衡。气溶胶中表面活性剂富集的程度直接取决于在溶液表面气泡破裂瞬间哪种吸附模式起控制作用。我们的机理描述解释了关于气溶胶液滴中表面活性剂富集的实验观察结果的多样性，并为理解与溶液表面集体效应（如破浪）相关的更复杂行为奠定了基础。
