In this work, sewage sludge flocculated with ferrous sulfate (SFS) was treated by one-step pyrolysis and ZnCl₂ activation to obtain magnetic Fe-containing carbon, which was used to remove elemental mercury (Hg⁰) from flue gas. When 30% ZnCl₂ was added to SFS (names as SFS-30), sulfides, chloride, magnetic Fe_xO_y, as well as a suitable BET surface area were produced during pyrolysis. SFS-30 showed a maximum mercury removal efficiency of 96.1%. The presence of O₂ and a low SO₂ concentration enhanced Hg⁰ removal, while H₂O vapor and a high concentration of SO₂ inhibited it. The addition of ZnCl₂ increased the BET surface area as well as the conversion of sulfate to sulfide, which were both beneficial for Hg⁰ removal. In addition, the generated magnetism during the pyrolysis process assisted in the recovery and utilization of SFS-30 in flue gas. After being magnetically separated from a mixture with fly ash, spent SFS-30 was thermally regenerated and recycled. After 8 Hg⁰ capture and regeneration cycles, the removal efficiency was not notably degraded, demonstrating that SFS-30 prepared by one-step pyrolysis with ZnCl₂ activation can be used for Hg⁰ removal. The results of this study have guiding significance for practical engineering applications of this material.

在这项工作中，用硫酸亚铁（SFS）絮凝的污水污泥通过一步热解和ZnCl ₂活化处理获得磁性含铁碳，用于去除烟气中的元素汞（Hg ⁰）。当将 30% ZnCl ₂添加到 SFS（名称为 SFS-30）时，在热解过程中会产生硫化物、氯化物、磁性 Fe _x O _y以及合适的 BET 表面积。SFS-30 的最大汞去除效率为 96.1%。O ₂和低 SO ₂浓度的存在增强了 Hg ^{0 的}去除，而 H ₂ O 蒸汽和高浓度的 SO ₂抑制了它。添加 ZnCl ₂增加了 BET 表面积以及硫酸盐向硫化物的转化率，这两者都有利于 Hg ^{0 的}去除。此外，热解过程中产生的磁性有助于烟气中SFS-30的回收利用。在从粉煤灰混合物中磁性分离后，用过的 SFS-30 被热再生和回收。经过 8 次 Hg ⁰捕获和再生循环后，去除效率没有明显下降，表明一步热解和 ZnCl ₂活化制备的 SFS-30可用于 Hg ⁰移动。本研究结果对该材料的实际工程应用具有指导意义。