Zhang Jun, Zhao Chunbao, Zhou Qiang, Hou Pingping, Li Xiao, Zhao Wei
School of Electronic Information, Nanjing Vocational College of Information Technology, Nanjing 210023, China.
School of Energy and Mechanical Engineering, Nanjing Normal University, Nanjing 210023, China.
ACS Omega. 2024 Aug 9;9(33):35837-35844. doi: 10.1021/acsomega.4c04630. eCollection 2024 Aug 20.
In the present work, CCl-adsorbed activated carbon pretreated by the mechanochemical method (CCl-AC) was produced for gas-phase mercury capture. The physicochemical properties of the CCl-AC sorbent were analyzed via N adsorption, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The mercury capture performance of the CCl-AC sorbent under different flue gas components was investigated in a fixed-bed experimental device. The programmed temperature desorption of mercury was used to determine the mercury capture product of the spent CCl-AC. Finally, the mass transfer factor model proposed by Fulazzaky was used to analyze mercury capture on the CCl-AC for clarifying its characteristics. The results showed that the prepared CCl-AC can be used as a mercury sorbent because of its high mercury capture performance. Mercury capture by the CCl-AC was interfered by SO and promoted by O and HO. Hg-temperature programmed desorption (Hg-TPD) analysis indicated that the main mercury capture products of the CCl-AC were HgCl and HgO. Because of the presence of SO in flue gas, there was a little HgSO formation on the sorbent. XPS analysis showed that the functional group of C-Cl played the dominant role in Hg capture, and part of the C-Cl groups were converted into Cl after mercury capture. The mercury desorption energy of the spent CCl-AC was 50.49 kJ/mol and stronger compared with that of raw activated carbon. Mass transfer analysis displayed that surface adsorption was the main form at the beginning of mercury adsorption, and the external mass transfer was the mercury adsorption rate-controlling step. Then, mercury adsorption entered the second stage; internal diffusion adsorption stage with internal mass transfer became the adsorption rate control step.
在本工作中，制备了通过机械化学方法预处理的用于气相汞捕集的CCl吸附活性炭（CCl-AC）。通过N吸附、扫描电子显微镜（SEM）和X射线光电子能谱（XPS）分析了CCl-AC吸附剂的物理化学性质。在固定床实验装置中研究了CCl-AC吸附剂在不同烟气成分下的汞捕集性能。采用汞程序升温脱附法测定了废CCl-AC的汞捕集产物。最后，利用Fulazzaky提出的传质因子模型分析了CCl-AC上的汞捕集情况，以阐明其特性。结果表明，所制备的CCl-AC因其高汞捕集性能可作为汞吸附剂。CCl-AC对汞的捕集受到SO的干扰，而受到O和HO的促进。汞程序升温脱附（Hg-TPD）分析表明，CCl-AC的主要汞捕集产物为HgCl和HgO。由于烟气中存在SO，吸附剂上有少量HgSO生成。XPS分析表明，C-Cl官能团在汞捕集中起主导作用，部分C-Cl基团在汞捕集后转化为Cl。废CCl-AC的汞脱附能为50.49 kJ/mol，比原始活性炭的更强。传质分析表明，汞吸附开始时表面吸附是主要形式，外部传质是汞吸附速率控制步骤。然后，汞吸附进入第二阶段；内部扩散吸附阶段，内部传质成为吸附速率控制步骤。
