Shi Zhiqiang, Xu Miao, Wu Lingyan, Du Haiyan, Ji Te, Wu Jiayuan, Niu Zuoshun, Yang Yi
Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China.
Qingdao Engineering Research Center for Rural Environment, College of Resource and Environment, Qingdao Agricultural University, Qingdao 266109, China.
Sci Total Environ. 2024 Nov 20;952:175950. doi: 10.1016/j.scitotenv.2024.175950. Epub 2024 Aug 31.
Information on the emission of coal combustion-sourced magnetite nanoparticles (MNPs) is lacking, which is critical for their health-related risks. In this study, MNPs in coal fly ashes (CFAs) from various coal-fired power plants (CFPPs) in China equipped with various dust removal devices were extracted and quantified using single particle ICP-MS. The number concentrations of MNPs in CFAs captured by dust removal increased with stage, while their size decreased. Among all the dust removal devices, electrostatic-fabric-integrated precipitators showed the best removal of MNPs. Furthermore, throughout all the coal combustion by-products in a typical CFPP, MNPs in EFA (fly ash escaped from the stack) showed the highest number concentration (1.2 × 10 particles/mg) and lowest size (78 nm). Although the mass of CFA escaping through the stack is extremely low, it still had an emission rate of 1.9 × 10 particles/h, contributing 3.56 % of the total emissions of MNPs in number. In addition, the purity of MNPs and their associated toxic metals showed a size-dependent variation pattern. As the particle size of MNPs decreased, the proportion of Fe in MNPs increased from 43 % in bottom ash (BA) to 84 % in EFA, while the abundance of trace toxic metals in EFA was 3.3 times higher than that of BA. These MNPs with the highest purity can adsorb elevated concentrations of toxic metals, and can be discharged directly into the atmosphere, posing a risk of synergistic toxicity.
关于煤燃烧源磁铁矿纳米颗粒（MNPs）的排放信息尚缺，而这对于其健康相关风险至关重要。在本研究中，利用单颗粒电感耦合等离子体质谱法对中国配备各种除尘装置的不同燃煤电厂（CFPPs）的粉煤灰（CFAs）中的MNPs进行了提取和定量分析。除尘装置捕集的CFAs中MNPs的数量浓度随阶段增加，而其尺寸减小。在所有除尘装置中，静电布袋组合式除尘器对MNPs的去除效果最佳。此外，在一个典型CFPP的所有煤燃烧副产物中，EFA（从烟囱逃逸的飞灰）中的MNPs数量浓度最高（1.2×10颗粒/毫克）且尺寸最小（78纳米）。尽管通过烟囱逃逸的CFA质量极低，但其排放速率仍为1.9×10颗粒/小时，占MNPs总排放数量的3.56%。此外，MNPs及其相关有毒金属的纯度呈现出尺寸依赖性变化模式。随着MNPs粒径减小，MNPs中Fe的比例从底灰（BA）中的43%增至EFA中的84%，而EFA中痕量有毒金属的丰度比BA高3.3倍。这些纯度最高的MNPs能够吸附更高浓度的有毒金属，并可直接排放到大气中，构成协同毒性风险。
