由于基于OH的氧化,溶解有机物质的碳同位素分离
Yunsong Zheng1, Yuxuan Tan2, Zhenchen Wan1
1State Key Laboratory of Geomicrobiology and Environmental Changes, China University of Geosciences, 68 Jincheng Street, Wuhan 430078, P. R. China.
Environmental science & technology
|May 2, 2025
概括
在溶解有机物 (DOM) 中量化基 (•OH) 氧化具有挑战性. 这项研究引入了一种基于同位素的新方法来测量OH氧化.
科学领域:
- 环境化学环境化学
- 同位素地球化学 同位素地球化学
- 有机地化学 有机地化学
背景情况:
- 由基 (•OH) 驱动的氧化对于溶解有机物 (DOM) 的转化和碳循环至关重要.
- 在环境科学中,量化OH氧化途径对DOM降解和CO2产生的特定贡献仍然是一个重大挑战.
研究的目的:
- 开发和应用一种基于碳同位素的新方法,以定量评估基于OH的氧化对DOM转化和CO2排放的贡献.
- 为了区分OH介导的DOM氧化与其他降解途径,如光化学和微生物过程.
主要方法:
- DOM及其氧化产物 (CO2) 的联合度和碳同位素分析 (δ13C).
- 对各种有机化合物和沉积物DOM的13C丰富系数 (ε值) 的分析.
- 应用终端混合模型来量化OH基矿化贡献.
主要成果:
- 对于芳香化合物 (-8.1‰至 -8.9‰),有机酸 (-4.2‰至 -28.9‰) 和沉积物DOM (-13.0‰) 的OH氧化,确定了不同的13C丰富系数 (ε值).
- 这些ε值明显比与光化学和微生物过程相关的值更为负,从而可以识别机制.
- 在特定的实验条件下,OH基矿化在二氧化碳总排放中的比例在20.9%至39.8%之间,明显高于空气氧化 (2%).
- 无机碳脱气被确定为沉积物氧化过程中二氧化碳排放的主要贡献者.
结论:
- 开发的基于同位素的工具提供了一种定量方法来评估OH氧化在DOM降解和CO2排放中的作用.
- 这些发现突出了基于OH的氧化对DOM碳流的显著,但经常被低估的贡献.
- 这种方法使得在各种环境中更好地理解和建模DOM转换过程.
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