Enhanced Iron Solubility at Low pH in Global Aerosols
Enhanced Iron Solubility at Low pH in Global Aerosols
复制标题
DOI：
10.3390/atmos9050201
复制
发表时间：
2018-05
期刊：
影响因子：
--
通讯作者：
E. Ingall;Yan Feng;Amelia F. Longo;B. Lai;R. Shelley;W. Landing;P. Morton;A. Nenes;N. Mihalopoulos;K. Violaki;Yuan Gao;S. Sahai;Erin Castorina
中科院分区：
文献类型：
--
作者：
E. Ingall;Yan Feng;Amelia F. Longo;B. Lai;R. Shelley;W. Landing;P. Morton;A. Nenes;N. Mihalopoulos;K. Violaki;Yuan Gao;S. Sahai;Erin Castorina
利用基于同步辐射的铁近边X射线吸收光谱法对气溶胶铁的成分和氧化态进行了检测。通过将基于同步辐射的技术与水浸出液分析相结合，对从南大洋和大西洋多个地点以及印度诺伊达、百慕大和地中海东部（克里特岛）采集的样本，评估了氧化态和矿物学对气溶胶铁溶解度的影响。这些采样地点采集到了来自不同源区的含铁气溶胶，这些源区受到不同的海洋、矿物粉尘和人为影响。在所有地点，pH值对气溶胶铁的溶解度具有主导影响。当气溶胶样本的pH值接近中性时，铁的溶解度平均为3.4%；当样本的pH值低于4时，铁的溶解度增加到35%。这种观测到的气溶胶铁溶解度曲线与对气溶胶样本中主要含铁相Fe(III)氧化物溶解度的热力学预测是一致的。源区和传输路径也是影响铁溶解度的重要因素，因为来自人口密集地区或经过这些地区的样本往往含有更多的可溶性铁。尽管酸度似乎在全球范围内影响气溶胶铁的溶解度，但所有样本之间的直接关系因人为影响、气溶胶缓冲能力、矿物学和物理过程等因素而变得复杂。
The composition and oxidation state of aerosol iron were examined using synchrotron-based iron near-edge X-ray absorption spectroscopy. By combining synchrotron-based techniques with water leachate analysis, impacts of oxidation state and mineralogy on aerosol iron solubility were assessed for samples taken from multiple locations in the Southern and the Atlantic Oceans; and also from Noida (India), Bermuda, and the Eastern Mediterranean (Crete). These sampling locations capture iron-containing aerosols from different source regions with varying marine, mineral dust, and anthropogenic influences. Across all locations, pH had the dominating influence on aerosol iron solubility. When aerosol samples were approximately neutral pH, iron solubility was on average 3.4%; when samples were below pH 4, the iron solubility increased to 35%. This observed aerosol iron solubility profile is consistent with thermodynamic predictions for the solubility of Fe(III) oxides, the major iron containing phase in the aerosol samples. Source regions and transport paths were also important factors affecting iron solubility, as samples originating from or passing over populated regions tended to contain more soluble iron. Although the acidity appears to affect aerosol iron solubility globally, a direct relationship for all samples is confounded by factors such as anthropogenic influence, aerosol buffer capacity, mineralogy and physical processes.