Aqueous phase oxidation of bisulfite influenced by nitrate and its photolysis
Aqueous phase oxidation of bisulfite influenced by nitrate and its photolysis
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硝酸盐影响亚硫酸氢盐的水相氧化及其光解
DOI：
10.1016/j.scitotenv.2021.147345
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发表时间：
2021
影响因子：
9.8
通讯作者：
Wang Lin
中科院分区：
文献类型：
--
作者：
Chen Lu;Kong Lingdong;Tong Songying;Yang Kejing;Jin Shengyan;Wang Chao;Xia Lianghai;Wang Lin
硝酸盐气溶胶在大气中无处不在。颗粒相和水相中的硝酸盐通过吸湿和光解作用影响大气中的各种化学过程。硝酸光解对so2非均相氧化的影响一直是人们关注的问题。然而，硝酸盐对大气硫酸盐气溶胶非均相水相形成的影响尚不十分清楚。研究了不同条件下硝酸盐对亚硫酸氢盐水相氧化的影响。结果表明，硝酸盐光解作用能促进亚硫酸氢盐氧化成硫酸盐，特别是在有O2存在的情况下。发现pH对反应有显著影响，硫酸铵通过调节溶液pH对提高水相硫酸盐产量有显著影响。卤素化学、硝酸盐及其光化学和S （IV）水氧化之间存在明显的协同作用，特别是硝酸盐及其光解氧化和S （IV）在酸性溶液中自由基链氧化产生的中间产物对卤素离子的氧化，导致卤素的氧化还原循环与亚硫酸氢盐的氧化耦合，促进亚硫酸氢盐的连续水氧化和硫酸盐的形成。此外，还揭示了硝酸盐本身在亚硫酸氢盐水相氧化中的作用。这些结果为研究so2在云雾滴和霾颗粒中的非均相水相氧化途径和机理提供了新的思路。
Nitrate aerosol is ubiquitous in the atmosphere. Nitrate in the particulate and aqueous phase can affect various atmospheric chemical processes through its hygroscopicity and photolysis. The impacts of nitrate photolysis on the heterogeneous oxidation of SO2have been attracting attention. However, the influence of nitrate on heterogeneous aqueous phase formation of atmospheric sulfate aerosol is still not very clear. In this study, the effects of nitrate on aqueous phase oxidation of bisulfite under different conditions were investigated. Results show that nitrate photolysis can promote the oxidation of bisulfite to sulfate, especially in the presence of O2. It is found that pH plays a significant role in the reaction, and ammonium sulfate has significant impacts on the enhancement of aqueous phase sulfate production through regulating the pH of solution. An apparent synergism is found among halogen chemistry, nitrate and its photochemistry and S (IV) aqueous oxidation, especially the oxidation of halide ions by nitrate and its photolysis and by the intermediate products produced by the free radical chain oxidation of S (IV) in acidic solution, leading to the coupling of the redox cycle of halogen with the oxidation of bisulfite, which promotes the continuous aqueous oxidation of bisulfite and the formation of sulfate. In addition, the role of nitrate itself in the aqueous phase oxidation of bisulfite is revealed. These results provide a new insight into the heterogeneous aqueous phase oxidation pathways and mechanisms of SO2in cloud and fog droplets and haze particles.