Photosensitized Degradation of DMSO Initiated by PAHs at the Air-Water Interface, as an Alternative Source of Organic Sulfur Compounds to the Atmosphere
Photosensitized Degradation of DMSO Initiated by PAHs at the Air-Water Interface, as an Alternative Source of Organic Sulfur Compounds to the Atmosphere
复制标题
PAH 在空气-水界面引发 DMSO 的光敏降解，作为大气中有机硫化合物的替代来源
DOI：
10.1029/2021jd035346
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发表时间：
2021-11-27
影响因子：
4.4
通讯作者：
Gligorovski, Sasho
中科院分区：
文献类型：
--
作者：
Jiang, Haoyu;Carena, Luca;Gligorovski, Sasho
有机化合物在水面上的光化学反应导致气相分子的形成，这可能有助于在大气中形成新的颗粒。在这里，我们观察到有机硫(OS)化合物的形成，这些化合物是已知的二次有机气溶胶(SOA)的前体，在含有典型的多环芳烃(PAHs)的水溶液中照射后形成，这些多环芳烃(PAHs)包括芘、荧菲和菲以及二甲基亚砜(DMSO)。用暂态吸收光谱测定了PAHs(3)的激发三重态与DMSO的反应活性，并在反应吉布斯能的理论计算基础上提出了DMSO降解的初步反应机理。利用新型膜进样-单光子电离飞行时间质谱仪，我们观察到甲烷磺酸、甲磺酸、甲磺酰甲烷、甲磺酸乙酯、羟基甲磺酸和2-羟基乙基甲磺酸的快速生成。这些结果表明，海面上普遍存在的PAHs和DMSO可能代表了白天OS化合物的另一种来源，即在未来的模型中应该考虑的光化学过程，以更好地描述大气中的SOA形成过程。
The photochemical reactions of organic compounds at the water surface lead to the formation of gas-phase molecules that may contribute to new particle formation in the atmosphere. Here, we observe the formation of organic sulfur (OS) compounds that are known secondary organic aerosol (SOA) precursors, upon irradiation of aqueous solutions containing typical polycyclic aromatic hydrocarbons (PAHs) such as pyrene, fluoranthene, and phenanthrene as well as dimethylsulfoxide (DMSO). The reactivity between the excited triplet states of PAHs ((3)PAHs*) and DMSO was determined by transient absorption spectroscopy and a tentative reaction mechanism for DMSO degradation was proposed, supported by theoretical calculations of the reaction Gibbs energies. In all cases, we observe rapid formation of methanesulfonic acid, methanesulfinic acid, methylsulfonylmethane, ethyl methanesulfonate, hydroxymethanesulfonic acid, and 2-hydroxyethanesulfonic acid by use of novel membrane inlet-single photon ionization-time of flight mass spectrometry. These results suggest that ubiquitous PAHs and DMSO at the sea surface may represent an alternative source of OS compounds during daytime, through photochemical processes that should be considered in future models to better represent the SOA formation processes in the atmosphere.