Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering , Jiangnan University , Wuxi 214122 , P. R. China.
Environ Sci Technol. 2020 Feb 4;54(3):1992-2001. doi: 10.1021/acs.est.9b06736. Epub 2020 Jan 14.
The existing technologies to control Hg emissions from coal-fired power plants can be improved to achieve the centralized control of Hg emissions, which continue to pose a risk of Hg exposure to human populations. In this work, MoS@γ-FeO, formed by the sulfuration of phosphomolybdic acid (HPMo)-grafted γ-FeO, was developed as a magnetic and regenerable sorbent to recover gaseous Hg from coal-fired flue gas as a cobenefit to the use of wet electrostatic precipitators. The thermal stability of γ-FeO was notably enhanced by HPMo grafting; thus, the magnetization of MoS@γ-FeO hardly decreased during the application. The kinetic analysis indicates that the chemical adsorption of gaseous Hg was mainly dependent on the amounts of surface S and surface adsorption sites. Although the amount of S on sulfurated γ-FeO decreased after HPMo grafting, the amount of surface adsorption sites significantly increased due to the formation of a layered MoS structure on the surface. Therefore, the ability of sulfurated γ-FeO to capture Hg was improved considerably after HPMo grafting. Furthermore, low concentrations of gaseous Hg in coal-fired flue gas can be gradually enriched by at least 1000 times by MoS@γ-FeO, which facilitates the recovery and centralized control of gaseous Hg in flue gas.
现有的燃煤电厂汞排放控制技术可以得到改进，以实现汞排放的集中控制，这将继续对人群暴露于汞的风险构成威胁。在这项工作中，通过磷钼酸（HPMo）接枝γ-FeO 的硫化作用，合成了 MoS@γ-FeO，作为一种磁性和可再生的吸附剂，从燃煤烟气中回收气态汞，作为湿式静电除尘器应用的副产物。HPMo 接枝显著提高了 γ-FeO 的热稳定性；因此，MoS@γ-FeO 的磁化强度在应用过程中几乎没有下降。动力学分析表明，气态汞的化学吸附主要取决于表面 S 和表面吸附位的数量。尽管硫代 γ-FeO 上的 S 含量在 HPMo 接枝后减少，但由于表面上形成了层状 MoS 结构，表面吸附位的数量显著增加。因此，HPMo 接枝后，硫代 γ-FeO 捕获汞的能力得到了显著提高。此外，MoS@γ-FeO 可以将燃煤烟气中低浓度的气态汞至少富集 1000 倍，这有利于回收和集中控制烟气中的气态汞。
