State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Joint Laboratory of Environmental Pollution Process and Control in Guangdong-Hong Kong-Macao Greater Bay Area, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China.
Longhua Center for Disease Control and Prevention of Shenzhen, Shenzhen 518109, China.
Sci Total Environ. 2022 Sep 10;838(Pt 1):155974. doi: 10.1016/j.scitotenv.2022.155974. Epub 2022 May 16.
Deposition of anthropogenic aerosols may contribute significantly to dissolved Fe in the open ocean, affecting marine primary production and biogeochemical cycles; however, fractional solubility of Fe is not well understood for anthropogenic aerosols. This work investigated mass fractions, solubility, speciation and isotopic compositions of Fe in coal and municipal waste fly ash. Compared to desert dust (3.1 ± 1.1%), the average mass fraction of Fe was higher in coal fly ash (6.2 ± 2.7%) and lower in municipal waste fly ash (2.6 ± 0.4%), and the average Fe/Al ratios were rather similar for the three types of particles. Municipal waste fly ash showed highest Fe solubility (1.98 ± 0.43%) in acetate buffer (pH: 4.3), followed by desert dust (0.43 ± 0.30%) and coal fly ash (0.24 ± 0.28%), suggesting that not all the anthropogenic aerosols showed higher Fe solubility than desert dust. For the samples examined in our work, amorphous Fe appeared to be an important controlling factor for Fe solubility, which was not correlated with particle size or BET surface area. Compared to desert dust (-0.05‰ to 0.21‰), coal and municipal waste fly ash showed similar or even higher δFe values for total Fe (range: 0.05‰ to 0.75‰), implying that the presence of coal or municipal waste fly ash may not be able to explain significantly smaller δFe values reported for total Fe in ambient aerosols affected by anthropogenic sources.
人为气溶胶的沉积可能会显著增加开阔海域中溶解态铁的含量，从而影响海洋初级生产力和生物地球化学循环；然而，对于人为气溶胶，铁的分数溶解度还没有得到很好的理解。本工作研究了煤和城市垃圾飞灰中铁的质量分数、溶解度、形态和同位素组成。与沙漠尘（3.1±1.1%）相比，煤飞灰中的铁质量分数（6.2±2.7%）较高，而城市垃圾飞灰中的铁质量分数（2.6±0.4%）较低，三种类型的颗粒的平均铁/铝比值相当相似。城市垃圾飞灰在醋酸盐缓冲液（pH：4.3）中显示出最高的铁溶解度（1.98±0.43%），其次是沙漠尘（0.43±0.30%）和煤飞灰（0.24±0.28%），这表明并非所有人为气溶胶的铁溶解度都高于沙漠尘。对于我们工作中检查的样品，无定形铁似乎是铁溶解度的一个重要控制因素，而与粒径或 BET 表面积无关。与沙漠尘（-0.05‰至 0.21‰）相比，煤和城市垃圾飞灰中的总铁的δFe 值相似甚至更高（范围：0.05‰至 0.75‰），这意味着煤或城市垃圾飞灰的存在可能无法解释在人为源影响的环境气溶胶中总铁的 δFe 值较小的情况。
