气候变化领域集成服务门户(CCPortal): Molecular-scale description of interfacial mass transfer in phase-separated aqueous secondary organic aerosol

CCPortal

DOI	10.5194/acp-21-17687-2021
	Molecular-scale description of interfacial mass transfer in phase-separated aqueous secondary organic aerosol
	Lbadaoui-Darvas M.; Takahama S.; Nenes A.
发表日期	2021
ISSN	1680-7316
起始页码	17687
结束页码	17714
卷号	21 期号:23
英文摘要	Liquid-liquid phase-separated (LLPS) aerosol particles are known to exhibit increased cloud condensation nuclei (CCN) activity compared to well-mixed ones due to a complex effect of low surface tension and non-ideal mixing. The relation between the two contributions as well as the molecular-scale mechanism of water uptake in the presence of an internal interface within the particle is to date not fully understood. Here we attempt to gain understanding in these aspects through steered molecular dynamics simulation studies of water uptake by a vapor-hydroxy-cis-pinonic acid-water double interfacial system at 200 and 300ĝ€¯K. Simulated free-energy profiles are used to map the water uptake mechanism and are separated into energetic and entropic contributions to highlight its main thermodynamic driving forces. Atmospheric implications are discussed in terms of gas-particle partitioning, intraparticle water redistribution timescales and water vapor equilibrium saturation ratios. Our simulations reveal a strongly temperature-dependent water uptake mechanism, whose most prominent features are determined by local extrema in conformational and orientational entropies near the organic-water interface. This results in a low core uptake coefficient (ko/wCombining double low line0.03) and a concentration gradient of water in the organic shell at the higher temperature, while entropic effects are negligible at 200ĝ€¯K due to the association-entropic-Term reduction in the free-energy profiles. The concentration gradient, which results from non-ideal mixing-and is a major factor in increasing LLPS CCN activity-is responsible for maintaining liquid-liquid phase separation and low surface tension even at very high relative humidities, thus reducing critical supersaturations. Thermodynamic driving forces are rationalized to be generalizable across different compositions. The conditions under which single uptake coefficients can be used to describe growth kinetics as a function of temperature in LLPS particles are described. © Copyright:
语种	英语
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/246397
作者单位	Laboratory of Atmospheric Processes and Their Impacts, School of Architecture, Civil and Environmental Engineering, Lausanne, 1015, Switzerland; Center of Studies on Air Quality and Climate Change, Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas, Patras, 26504, Greece
推荐引用方式 GB/T 7714	Lbadaoui-Darvas M.,Takahama S.,Nenes A.. Molecular-scale description of interfacial mass transfer in phase-separated aqueous secondary organic aerosol[J],2021,21(23).
APA	Lbadaoui-Darvas M.,Takahama S.,&Nenes A..(2021).Molecular-scale description of interfacial mass transfer in phase-separated aqueous secondary organic aerosol.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(23).
MLA	Lbadaoui-Darvas M.,et al."Molecular-scale description of interfacial mass transfer in phase-separated aqueous secondary organic aerosol".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.23(2021).