School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, P. R. China.
Environ Sci Technol. 2022 Jan 4;56(1):642-651. doi: 10.1021/acs.est.1c06787. Epub 2021 Dec 13.
In this work, sulfureted phosphotungstic acid-grafted γ-FeO (HPW/γ-FeO) was investigated as a regenerable monolithic sorbent to recover gaseous Hg upstream of wet flue gas desulfurizations (FGDs), and the effects of HCl, SO, and HO on the chemical adsorption of Hg onto sulfureted HPW/γ-FeO were investigated with Hg balance analysis and kinetic analysis. Hg conversion over sulfureted HPW/γ-FeO was remarkably promoted in the presence of HCl, and most Hg was catalytically oxidized to HgCl. Moreover, the chemical adsorption of Hg was notably restrained as the key species for Hg transformation to HgS (i.e., S) was rapidly oxidized by Cl*. However, the effect of HCl on Hg conversion over sulfureted HPW/γ-FeO was almost counteracted by HO and SO as they competed with physically adsorbed Hg and S for the consumption of Cl*. Therefore, the chemical adsorption of Hg onto sulfureted HPW/γ-FeO in the presence of SO and HO was slightly inhibited by HCl, and only a small amount of HgCl was formed. Moreover, sulfureted HPW/γ-FeO exhibited a moderate ability for gaseous HgCl adsorption. As a result, sulfureted HPW/γ-FeO showed excellent performance in recovering Hg from the flue gas upstream of the FGDs for the centralized control of Hg emitted from coal-fired plants.
在这项工作中，研究了负载磷钨酸硫化亚铁（HPW/γ-FeO）作为一种可再生整体式吸附剂，用于在湿法烟气脱硫（FGD）上游回收气态 Hg，并用 Hg 平衡分析和动力学分析研究了 HCl、SO 和 HO 对 Hg 化学吸附到硫化 HPW/γ-FeO 的影响。在 HCl 的存在下，硫化 HPW/γ-FeO 上的 Hg 转化率显著提高，并且大部分 Hg 被催化氧化为 HgCl。此外，Hg 的化学吸附受到明显抑制，因为 Hg 向 HgS（即 S）转化的关键物种被 Cl迅速氧化。然而，HCl 对硫化 HPW/γ-FeO 上 Hg 转化率的影响几乎被 HO 和 SO 抵消，因为它们与物理吸附的 Hg 和 S 竞争，消耗 Cl。因此，在 SO 和 HO 的存在下，Hg 化学吸附到硫化 HPW/γ-FeO 上受到 HCl 的轻微抑制，仅形成少量 HgCl。此外，硫化 HPW/γ-FeO 对气态 HgCl 的吸附能力适中。因此，硫化 HPW/γ-FeO 在从 FGD 上游的烟道气中回收 Hg 方面表现出优异的性能，用于集中控制燃煤电厂排放的 Hg。
