微滴表面驱动和加速以质子控制的大小依赖的酸盐光解
Xiaowu Zhang1, Qishen Huang1, Yu-Xin Liu1
1School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Journal of the American Chemical Society
|June 2, 2025
概括
颗粒酸盐光解速率因液滴大小和pH值而有所不同. 这项研究揭示了微滴中表面驱动,大小依赖的光解,解释了反应性再生中的大气变化.
科学领域:
- 大气化学
- 环境科学
- 物理化学
背景情况:
- 颗粒酸盐光解释放出反应性氧化物种 (HONO和NOx),影响空气质量和气候.
- 现有关于酸盐光解速率的数据显示出显著的变化,对气溶中的质子和空气-水接口的作用尚不清楚.
- 了解这些过程对于准确的大气模型至关重要.
研究的目的:
- 研究pH和滴粒大小对酸盐光解速率系数的影响.
- 阐明酸盐光解中的质子和空气-水界面的作用.
- 解决报告中的酸盐光解速率的差异,并解释大气变化.
主要方法:
- 使用共聚焦拉曼光谱和气溶光学针技术.
- 在pH (3.2-7.4) 和半径 (3.7μm至6.0mm) 范围内测量酸盐光解速率系数 (j).
- 分析了光解速率与pH值和液滴大小的依赖性,确定了临界点.
主要成果:
- 酸盐光解速率系数在5.28×10−8到9.07×10−6s−1之间.
- 在pH值6. 5以下,光解率与pH值无关,在pH值6. 5以上,光解率下降.
- 确定了一个倾斜点半径 (r* = 706 μm),在此下,光解与半径相反,表明表面占主导地位.
结论:
- 酸盐光解主要发生在微滴的空气-水界面.
- 鉴定的尺寸依赖光解机制解释了大气颗粒酸盐光解速率的观察变化.
- 这些发现对于改善大气中循环和空气质量模型至关重要.
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