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在水相中通过NO₃^•的氧化过程中,棕色碳的光学变化和分子转化

Yu Lei¹, Xin Lei², Ge Tian¹

¹Key Laboratory of Photochemistry, Institute of Chemistry Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, Beijing 100190, P. R. China.

Environmental science & technology

|February 6, 2024

概括

夜间的基 (NO3•) 氧化会根据其来源改变棕色碳 (BrC) 的光学特性. 这项研究揭示了BrC.

科学领域:

大气化学大气化学
环境科学环境科学
频谱学是一种光谱学.

背景情况:

棕色碳 (BrC) 的夜间氧化由酸盐基 (NO3•) 显著影响其大气辐射强迫.
3•氧化对大气水中的BrC光学性质的特定影响以及潜在的机制尚不清楚.

研究的目的:

为了研究NO3•氧化对来自大气水中的不同来源的棕色碳 (BrC) 的光学特性的影响.
阐明参与碳NO3驱动转化反应的反应机制.
为了确定BrC作为大气水中的NO3•的沉积点的重要性.

主要方法:

BrC代理物暴露于NO3•的环境相关度下.
使用光谱光度学分析光学属性变化的分析.
使用里埃变换离子循环子子共振质谱法 (FT-ICR MS) 进行分子转换的表征.
通过短暂吸收光谱学和甲 (NaBH4) 减少实验来研究反应机制.

主要成果:

在NO3•暴露后,BrC中的光学变化与来源不同:燃烧生物质的BrC显示出增强的光吸收性,而城市气溶和性物质显示出漂白.
NO3• 在燃烧生物质的BrC中氧化形成的吸光化有机物种.
在城市气溶和性物质中,NO3•破坏了电荷转移复合体内的电子捐赠体,通过光谱学和还原实验确定.
实际BrCs (k = (1.8 ± 0.6) × 107 M<0xE1><0xB5><0x84>−1s−1) 的NO3•的测量速率常数明显高于单个有机碳 (OC) 组件.

结论:

在大气水中的NO3•氧化过程中,BrC的光学性质发生源依赖的变化.
根据BrC的来源,NO3•与BrC的反应涉及形成新的吸光物种或破坏电子捐赠体.
棕色碳代表了大气水中NO3•的大量,以前被低估的沉,影响大气化学和气候.
这项研究提供了关键的动力学和机械学的见解BrC老化NO3•,帮助气候影响评估.

关键词:

NO3• 没有.3•水槽可以使用.大气中的水相是大气中的水相.棕色碳是一种棕色碳.分子转化分子转化

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