当前位置: X-MOL 学术ACS Earth Space Chem. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Joint Impacts of Acidity and Viscosity on the Formation of Secondary Organic Aerosol from Isoprene Epoxydiols (IEPOX) in Phase Separated Particles
ACS Earth and Space Chemistry ( IF 2.9 ) Pub Date : 2019-12-10 , DOI: 10.1021/acsearthspacechem.9b00209
Yue Zhang 1, 2 , Yuzhi Chen 1 , Ziying Lei 3 , Nicole E. Olson 4 , Matthieu Riva 5 , Abigail R. Koss 6 , Zhenfa Zhang 1 , Avram Gold 1 , John T. Jayne 2 , Douglas R. Worsnop 2 , Timothy B. Onasch 2 , Jesse H. Kroll 6, 7 , Barbara J. Turpin 1 , Andrew P. Ault 3, 4 , Jason D. Surratt 1
Affiliation  

Isoprene-derived secondary organic aerosol (SOA) is mainly formed through acid-catalyzed reactive uptake of isoprene-derived epoxydiols (IEPOX) onto sulfate aerosol particles. The effect of IEPOX-derived SOA on the physicochemical properties of existing aerosols and resulting capacity for further SOA formation remains unclear. This study systematically examined the influences of IEPOX-derived SOA on the phase state, morphology, and acidity of pre-existing sulfate aerosol particles, as well as their implications on the reactivity and evolution of these particles. By combining aerosol thermodynamic and viscosity modeling, our predictions show that aerosol viscosity and acidity change drastically after IEPOX reactive uptake, with the aerosol becoming less acidic (increasing by up to 1.5 pH units) and more viscous by 7 orders of magnitude, thereby significantly reducing the diffusion time scale of the molecules inside the particles. Decreased aerosol acidity and increased viscosity co-contribute to a self-limiting effect where newly formed IEPOX-derived SOA inhibits additional multiphase chemical reactions of IEPOX. The relative contribution to the inhibitory effect of pH versus viscosity depends on the initial ratio of the IEPOX-to-inorganic sulfate aerosol, which differs between geographic regions. Moreover, reduced aerosol acidity and increased kinetic limitation to diffusion leading to lower hydronium ions and slower mixing times may impede other multiphase chemical processes after the formation of IEPOX-derived SOA. This study highlights important interconnections between physical and chemical properties of aerosol particles that come from interactions of inorganic and organic components, which jointly influence the evolution of atmospheric aerosols.

中文翻译:

酸度和粘度对相分离颗粒中异戊二烯环氧二醇(IEPOX)形成次级有机气溶胶的共同影响

异戊二烯衍生的二次有机气溶胶(SOA)主要是通过异戊二烯衍生的环氧二醇(IEPOX)的酸催化反应性吸收到硫酸盐气溶胶颗粒上而形成的。IEPOX衍生的SOA对现有气溶胶的物理化学性质的影响以及由此产生的进一步形成SOA的能力仍不清楚。这项研究系统地考察了IEPOX衍生的SOA对预先存在的硫酸盐气溶胶颗粒的相态,形态和酸度的影响,以及它们对这些颗粒的反应性和演化的影响。通过结合气溶胶热力学模型和黏度模型,我们的预测表明,IEPOX反应性吸收后,气溶胶黏度和酸度发生了急剧变化,其中气溶胶的酸性降低(最多增加1.5个pH单位),而粘稠度提高了7个数量级,从而显着降低了颗粒在内部的扩散时间。降低的气溶胶酸度和增加的粘度共同导致了自我限制效应,其中新形成的源自IEPOX的SOA抑制了IEPOX的其他多相化学反应。pH对粘度的抑制作用的相对贡献取决于IEPOX与无机硫酸盐气溶胶的初始比例,这在不同的地理区域之间是不同的。此外,降低的气溶胶酸度和增加的扩散动力学限制会导致更低的水合氢离子和较慢的混合时间,可能会阻碍形成IEPOX的SOA后的其他多相化学过程。
更新日期:2019-12-11
down
wechat
bug