Coal Fly Ash as a Source of Iron in Atmospheric Dust
Coal Fly Ash as a Source of Iron in Atmospheric Dust
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DOI：
10.1021/es204102f
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发表时间：
2012-02-21
影响因子：
11.4
通讯作者：
Grassian, Vicki H.
中科院分区：
文献类型：
--
作者：
Chen, Haihan;Laskin, Alexander;Grassian, Vicki H.
人为煤飞灰（FA）气溶胶可能是一个重要的来源，生物可利用的铁在开放的海洋。很少有测量比较大气铁的溶解度从人为气溶胶和其他来源。我们在这里报告的铁溶解的调查三个FA样品在酸性水溶液中，并比较亚利桑那州的测试粉尘（AZTD），矿物粉尘的参考材料的溶解度。pH值，模拟云处理，和太阳辐射对铁溶解度的影响进行了探讨。与先前报道的矿物粉尘结果相似，铝硅酸盐相中的铁提供了溶解铁的主要成分。FA的铁溶解度显著高于包含AZTD的结晶矿物的铁溶解度。模拟大气处理提高铁的溶解度，由于铝硅酸盐玻璃，FA颗粒中的主要材料的形态的显着变化。随着FA颗粒破碎成更小的碎片，铁不断释放到水溶液中。这些结果表明，溶解大气铁沉降通量的评估及其对海洋表面的地球化学的影响，应限制在源，环境pH值，铁形态，和太阳辐射。
Anthropogenic coal fly ash (FA) aerosol may represent a significant source of bioavailable iron in the open ocean. Few measurements have been made that compare the solubility of atmospheric iron from anthropogenic aerosols and other sources. We report here an investigation of iron dissolution for three FA samples in acidic aqueous solutions and compare the solubilities with that of Arizona test dust (AZTD), a reference material for mineral dust. The effects of pH, simulated cloud processing, and solar radiation on iron solubility have been explored. Similar to previously reported results on mineral dust, iron in aluminosilicate phases provides the predominant component of dissolved iron. Iron solubility of FA is substantially higher than of the crystalline minerals comprising AZTD. Simulated atmospheric processing elevates iron solubility due to significant changes in the morphology of aluminosilicate glass, a dominant material in FA particles. Iron is continuously released into the aqueous solution as FA particles break up into smaller fragments. These results suggest that the assessment of dissolved atmospheric iron deposition fluxes and their effect on the biogeochemistry at the ocean surface should be constrained by the source, environmental pH, iron speciation, and solar radiation.