在单个升起的微滴中直接量化pH值的变化以及酸盐和化物耗尽的动力学
Kyle J Angle1, Vicki H Grassian1
1Department of Chemistry and Biochemistry, University of California San Diego La Jolla CA 92093 USA vhgrassian@ucsd.edu.
Chemical science
|June 16, 2023
概括
水中的微滴比酸盐更快地失去化物,影响它们的湿度和pH值. 这种对气候和健康至关重要的酸性蒸发受到空气-水界面的气体分离的限制.
科学领域:
- 大气中的化学成分
- 环境科学环境科学
- 物理化学 物理化学
背景情况:
- 水性微滴和气溶显著影响人类健康和气候.
- 这些颗粒中的酸盐和化物减少会影响它们的湿度和pH值.
- 以前的研究表明,脱水过程中酸蒸发,但高相对湿度 (RH) 的速率仍然不清楚.
研究的目的:
- 通过酸 (HNO3) 和盐酸 (HCl) 从高RH的水性微滴中蒸发的酸和化物耗尽的动力学研究.
- 了解这些枯竭过程对微滴液体高度和pH的影响.
主要方法:
- 使用单个悬浮的微滴.
- 采用空腔增强的拉曼光谱法进行现场测量.
- 使用甘氨酸作为一种新的pH探测器,在几个小时内同时监测微滴组成和pH值.
主要成果:
- 从微滴中失去的速度比酸盐的损失更快.
- 计算的速率常数表明,耗尽主要受到空气-水界面和随后的气相分区形成的HCl或HNO3的限制.
- 酸蒸发甚至发生在高RH的完全水合液滴中.
结论:
- 这项研究阐明了高RH时微滴从酸蒸发的动力学.
- 这些发现强调了气相分离在控制酸盐和化物耗尽方面发挥的关键作用.
- 这些过程对于理解气溶云相互作用和大气化学是必不可少的.
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