| 引用本文: | 孙娟，丁喆正，易雅谊，陈彦奇，薛丽坤，王文兴，周学华.2022.实验室模拟研究硫酸铵和甘氨酸对乙醇醛与胺反应体系生成棕碳的影响[J].地球环境学报,13(2):226-239 |
| SUN Juan, DING Zhezheng, YI Yayi, CHEN Yanqi, XUE Likun, WANG Wenxing, ZHOU Xuehua.2022.The opposing influences of ammonium sulfate/glycine on the formation of brown carbon in glycolaldehyde with amine system in a laboratory simulation[J].Journal of Earth Environment,13(2):226-239 |
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| 摘要: |
| 二次有机气溶胶是有机气溶胶的重要组成部分。大气中羰基化合物与胺/铵反应可以产生吸光性有机气溶胶（如棕碳），对大气辐射和全球气候产生深刻影响。本文模拟研究了大气中硫酸铵和甘氨酸对乙醇醛与胺（如甲胺、甘氨酸）反应生成棕碳的影响。通过对反应溶液紫外—可见吸收光谱和反应动力学分析，发现硫酸铵对反应体系棕碳的生成起抑制作用，而甘氨酸和甲胺的混合可以协同促进棕碳生成；通过对产物进行质谱分析，发现反应机理主要为半缩醛/缩醛反应以及含氮化合物的亲核加成；通过对产物有机碳进行分析，发现当硫酸铵参与反应时，有利于大分子二次有机碳生成。这些发现对棕碳在大气中的形成途径、乙醇醛在化学模型中对棕碳形成的贡献以及对大气中其他羰基行为的预测具有重要意义。 |
| 关键词: 二次有机气溶胶 棕碳 实验室模拟 乙醇醛 硫酸铵 甘氨酸 甲胺 |
| DOI：10.7515/JEE222003 |
| CSTR： |
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| 基金项目:国家自然科学基金项目（21507070，91544213） |
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| The opposing influences of ammonium sulfate/glycine on the formation of brown carbon in glycolaldehyde with amine system in a laboratory simulation |
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SUN Juan, DING Zhezheng, YI Yayi, CHEN Yanqi, XUE Likun, WANG Wenxing, ZHOU Xuehua
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1. Environment Research Institute, Shandong University, Qingdao 266237, China
2. Qingdao Junray Intelligent Instrument Co., Ltd., Qingdao 266108, China
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| Abstract: |
| Background, aim, and scope Secondary organic aerosols (SOA) are important parts of organic aerosols. The reaction of carbonyl compounds with amine/ammonium can generate light-absorbing organic aerosol (i.e., brown carbon (BrC)) in the atmosphere, which affects both radiative forcing and global climate. This reaction has become an important aspect of atmospheric chemistry. In the aqueous reaction of glycolaldehyde (GAld) with amine/ammonium to form BrC, we aim to explore the different effects of ammonium sulfate (AS) /glycine (Gly) on the formation of BrC in this reaction system. Materials and methods Glycolaldehyde is the simplest hydroxycarbonyl compound in the atmosphere. We examined the ultraviolet-visible absorbance spectra, reaction kinetics, and the secondary organic carbon (SOC) masses of the mixed solutions of GAld. Moreover, we employed time-of-flight and ion trap mass spectrometry (LCMS-IT-TOF) to determine the reaction products. Results The results demonstrated that the absorbance and reaction rate of the products followed the order of GAld+methylamine (MA) +ASGAld+MA or GAld+Gly. Compared with the reaction of GAld with either MA or Gly, the GAld+MA+AS, GAld+Gly+AS, and GAld+MA+Gly reactions are increasingly favorable to produce the aqueous SOC. Furthermore, it was apt to form high-molecular-weight SOC with when AS participated in the reaction. Discussion After adding AS and Gly to the reaction system of GAld with amine, the two substances have opposite effects on BrC formation in the reaction system. These effects might be attributed to the changes of pH in the solutions, additional concentration variations of reactants with nitrogen (e.g., NH3, CH3NH2, and H2NCH2COO−), and the participation of NH3 and H2NCH2COO− in the reactions of GAld with amine after the addition of AS in GAld+MA or GAld+Gly and Gly in GAld+MA. In the GAld+MA+AS, GAld+Gly+AS reaction systems, AS reduces the pH value of the solution, thereby reducing the concentration of reactants and inhibiting the formation of BrC; in the GAld+MA+Gly reaction system, organic amines and inorganic ammonium jointly promote the formation of BrC. In the reaction process, the main reaction mechanism is the hemiacetal/acetal reaction of GAld, followed by nucleophilic addition reaction with nitrogen-containing substances to generate high molecular weight oligomers. Moreover, the mixed reaction systems can produce more secondary organic carbon than GAld with single MA and Gly. Conclusions The reaction rate agrees with the UV absorption, showing that AS inhibits BrC formation and the mixing of Gly and MA promotes BrC formation. The primary reaction mechanism is the hemiacetal/acetal reaction and nucleophilic attack. When AS participates in these reactions, it is conducive to the formation of macromolecular products. Recommendations and perspective The results have considerable implications on BrC formation in the atmosphere, the contribution of GAld to BrC formation in chemical models, and the predictions of the behaviors of other carbonyls in the atmosphere. |
| Key words: secondary organic aerosol brown carbon laboratory simulation glycolaldehyde ammonium sulfate glycine methylamine |
