Synergistic Reaction of SO2 with NO2 in Presence of H2O and NH3: A Potential Source of Sulfate Aerosol

International Journal of Molecular Sciences

卷:20

Zhiqiang Li¹  Chenxi Zhang²  Guochun Lv³  Xiaomin Sun³  Zehua Wang³  Ning Wang³ 

[1] Center for Optics Research and Engineering (CORE), Shandong University, Qingdao 266237, China;

[2] College of Biological and Environmental Engineering, Binzhou University, Binzhou 256600, China;

[3] Environment Research Institute, Shandong University, Jinan 250100, China;

关键词: sulfuric acid;    sulfur dioxide;    nitrogen dioxide;    synergistic oxidation;    hydrolysis reaction;   

DOI  :  10.3390/ijms20153746

来源: DOAJ

【 摘 要 】

Effect of H₂O and NH₃ on the synergistic oxidation reaction of SO₂ and NO₂ is investigated by theoretical calculation using the molecule system SO₂-2NO₂-nH₂O (n = 0, 1, 2, 3) and SO₂-2NO₂-nH₂O-mNH₃ (n = 0, 1, 2; m = 1, 2). Calculated results show that SO₂ is oxidized to SO₃ by N₂O₄ intermediate. The additional H₂O in the systems can reduce the energy barrier of oxidation step. The increasing number of H₂O molecules in the systems enhances the effect and promotes the production of HONO. When the proportion of H₂O to NH₃ is 1:1, with NH₃ included in the system, the energy barrier is lower than two pure H₂O molecules in the oxidation step. The present study indicates that the H₂O and NH₃ have thermodynamic effects on promoting the oxidation reaction of SO₂ and NO₂, and NH₃ has a more significant role in stabilizing product complexes. In these hydrolysis reactions, nethermost barrier energy (0.29 kcal/mol) can be found in the system SO₂-2NO₂-H₂O. It is obvious that the production of HONO is energetically favorable. A new reaction mechanism about SO₂ oxidation in the atmosphere is proposed, which can provide guidance for the further study of aerosol surface reactions.

【 授权许可】

Unknown