负载氯的分级多孔炭制备及其脱汞性能的研究

以纳米碳酸钙为模板，水稻秸秆为碳前驱体，采用共热解法制备了负载氯的分级多孔生物质炭。在模拟烟气条件下，利用固定床实验台架研究了生物质碳材料对烟气中的单质汞（Hg⁰）的脱除性能。采用扫描电镜（SEM）、透射电镜（TEM）、N₂吸附-脱附（BET）、程序升温脱附（Hg-TPD）以及X射线光电子能谱（XPS）等方法对材料进行表征。结果表明，盐酸浸渍不仅可去除模板产物生成多孔结构，并且有效地将氯负载到材料表面。负载氯的分级多孔炭B1C1-Cl2的比表面积和总孔容分别达到398.1 m²/g和0.4923 cm³/g。在120℃，空速（GHSV）为225000 h^-1时，脱汞效率可达95%。多孔结构有利于气体扩散，高比表面积为材料提供了更多的反应位点，微孔-介孔内表面上的C-Cl共价键为脱汞的主要化学吸附活性位点。

Synthesis of hierarchical porous carbon loaded with chlorine and its mercury removal performance

Chlorine-loaded hierarchical porous bio-char was prepared by co-pyrolysis using nano-CaCO₃ as template and rice straw as carbon precursor. The removal of mercury (Hg⁰) from flue gas by porous materials was studied on a fixed bed test bench with simulated flue gas. The materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption-desorption (BET), temperature programmed desorption (Hg-TPD) and X-ray photoelectron spectroscopy (XPS). The results show that HCl impregnation not only removes the products on the template to form porous structures but also effectively loads chlorine onto the surface of the material. The specific surface area and total pore volume of B1C1-Cl2 are 398.1 m²/g and 0.4923 cm³/g, respectively. When the GHSV is 225000 h^-1 at 120 ℃, the removal efficiency of Hg⁰ by chemical adsorption is up to 95%. The porous structure is beneficial to gas diffusion and the high specific surface area can provide more active sites. The covalent groups (C-Cl) participating in the Hg⁰ removal process are the dominant chemical adsorption sites on the inner micro-mesopore surface.