School of Resource and Environmental Sciences, Wuhan University, Wuhan, 430079, Hubei, People's Republic of China.
School of Information and Safety Engineering, Zhongnan University of Economics and Law, Wuhan, 430073, Hubei, People's Republic of China.
Environ Sci Pollut Res Int. 2020 Aug;27(24):30254-30264. doi: 10.1007/s11356-020-08133-4. Epub 2020 May 25.
The sewage sludge flocculated with ferrous sulfate (SFS) was prepared by one-step pyrolysis to obtain magnetic Fe-containing carbon. Results showed that only a small amount of FeO as well as extremely weak magnetism were observed at pyrolysis temperatures of less than 500 °C. SFS tended to exhibit intensive agglomeration, leading to the drastic increase of the crystalline-phase particle size at high pyrolysis temperature. The optimal pyrolysis temperature is 700 °C, corresponding to the production of some sulfides, an optimal content of FeO, and a suitable BET surface. Hg removal efficiency of SFS700 (SFS pyrolyzed at 700 °C) reached 80.7% at the reaction temperature of 125 °C. The presence of O and low concentration of SO enhanced the Hg removal, while the HO vapor and high SO concentration inhibited it. Meanwhile, good resistance for the adsorbent to moderate concentrations of SO and HO was observed. Moreover, the good magnetism performance is conducive to the recovery and utilization of the SFS700 in flue gas. Therefore, SFS can be used for Hg removal without any chemical modification after undergoing one-step pyrolysis and this study has guiding significance for the resource utilization and engineering practices.
采用一步热解法将硫酸亚铁（SFS）絮凝得到的污泥制备成磁性含碳铁。结果表明，在低于 500°C 的热解温度下，仅观察到少量的 FeO 和极弱的磁性。SFS 倾向于发生强烈的团聚，导致在高的热解温度下晶相颗粒尺寸急剧增加。最佳热解温度为 700°C，对应于一些硫化物的生成、FeO 的最佳含量和合适的 BET 表面积。在 125°C 的反应温度下，SFS700（在 700°C 下热解的 SFS）的 Hg 去除效率达到 80.7%。O 的存在和低浓度的 SO 增强了 Hg 的去除，而 HO 蒸汽和高浓度的 SO 则抑制了 Hg 的去除。同时，该吸附剂对中等浓度的 SO 和 HO 具有良好的抗性。此外，良好的磁性性能有利于 SFS700 在烟道气中的回收和利用。因此，SFS 无需经过任何化学改性即可进行一步热解，用于 Hg 的去除，该研究对资源利用和工程实践具有指导意义。
