Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
Environ Sci Technol. 2012 Oct 16;46(20):11119-27. doi: 10.1021/es302558m. Epub 2012 Sep 25.
In this study, iron solubility from six combustion source particles was investigated in acidic media. For comparison, a Chinese loess (CL) dust was also included. The solubility experiments confirmed that iron solubility was highly variable and dependent on particle sources. Under dark and light conditions, the combustion source particles dissolved faster and to a greater extent relative to CL. Oil fly ash (FA) yielded the highest soluble iron as compared to the other samples. Total iron solubility fractions measured in the dark after 12 h ranged between 2.9 and 74.1% of the initial iron content for the combustion-derived particles (Oil FA > biomass burning particles (BP) > coal FA). Ferrous iron represented the dominant soluble form of Fe in the suspensions of straw BP and corn BP, while total dissolved Fe presented mainly as ferric iron in the cases of oil FA, coal FA, and CL. Mössbauer measurements and TEM analysis revealed that Fe in oil FA was commonly presented as nanosized Fe(3)O(4) aggregates and Fe/S-rich particles. Highly labile source of Fe in corn BP could be originated from amorphous Fe form mixed internally with K-rich particles. However, Fe in coal FA was dominated by the more insoluble forms of both Fe-bearing aluminosilicate glass and Fe oxides. The data presented herein showed that iron speciation varies by source and is an important factor controlling iron solubility from these anthropogenic emissions in acidic solutions, suggesting that the variability of iron solubility from combustion-derived particles is related to the inherent character and origin of the aerosols themselves. Such information can be useful in improving our understanding on iron solubility from combustion aerosols when they undergo acidic processing during atmospheric transport.
在本研究中，我们研究了六种燃烧源颗粒在酸性介质中的铁溶解度。为了进行比较，还包括了中国黄土（CL）粉尘。溶解度实验证实，铁的溶解度具有高度可变性，且取决于颗粒源。在黑暗和光照条件下，与 CL 相比，燃烧源颗粒的溶解速度更快，溶解程度更大。与其他样品相比，油飞灰（FA）的可溶铁含量最高。在黑暗条件下，经过 12 小时后测量的总铁溶解分数在燃烧源颗粒（油 FA>生物质燃烧颗粒（BP）>煤 FA）中占初始铁含量的 2.9%至 74.1%之间。在 straw BP 和 corn BP 的悬浮液中，亚铁铁代表了铁的主要可溶形式，而在油 FA、煤 FA 和 CL 的情况下，总溶解铁主要以高铁形式存在。穆斯堡尔测量和 TEM 分析表明，油 FA 中的铁通常以纳米级 Fe3O4 聚集体和富 Fe/S 颗粒的形式存在。在 corn BP 中，铁的高反应性来源可能源于与富 K 颗粒内部混合的非晶态 Fe 形式。然而，煤 FA 中的铁主要以含铁铝硅酸盐玻璃和 Fe 氧化物的更不溶性形式存在。本文提供的数据表明，铁的形态因来源而异，是控制这些人为排放物在酸性溶液中溶解的重要因素，这表明燃烧源颗粒的铁溶解度的可变性与气溶胶本身的固有特性和来源有关。这些信息有助于提高我们对燃烧气溶胶在大气传输过程中经历酸性处理时的铁溶解度的理解。
