凹凸棒石(PG)负载MnOx催化剂脱除气态Hg0的研究

Hg0 removal by palygorskite (PG) supported MnOx catalyst

  • 摘要: 利用凹凸棒石(PG)负载Mn氧化物制备MnOx/PG催化剂并用于脱除模拟烟气中的Hg0,并采用比表面积分析(BET)、X射线衍射(XRD)、X射线光电子能谱(XPS)等技术对催化剂进行了分析表征。结果表明,MnOx和凹凸棒石的共同作用明显增强了对Hg0脱除性能,MnOx负载量为8%的MnOx/PG催化剂脱除Hg0的活性最高,在400 min内反应温度为210 ℃、空速为6000 h-1、汞质量浓度为80 μg/m3的条件下Hg0的脱除效率可达95%以上。O2对MnOx/PG催化剂脱除Hg0具有促进作用,而SO2和H2O具有抑制作用,但气氛中有O2存在时可明显减弱SO2的抑制作用。X射线衍射(XRD)、X射线光电子能谱分析(XPS)和程序升温脱附实验(TPD)等结果表明,活性组分MnOx在载体PG上分散良好,Hg0在MnOx/PG催化剂上的脱除过程包含了吸附、氧化、反应等步骤,生成了HgO和HgSO4并吸附在催化剂上。

     

    Abstract: The MnOx/PG catalysts were prepared by supporting Mn oxides to palygorskite (PG) and used to remove Hg0 in simulated flue gas, which were analyzd and characterized by the specific surface area analysis (BET), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that the co-effect of MnOx and PG significantly enhances the Hg0 removal performance; the MnOx/PG catalyst with 8% MnOx loading has the highest Hg0 removal activity. The Hg0 removal efficiency can maintain above 95% at 210 ℃ with a space velocity of 6000 h-1 and an inlet Hg0 concentration of 80 μg/m3 for 400 min. O2 can promote the Hg0 removal by MnOx/PG catalysts, while SO2 and H2O have inhibitory effects. In the presence of O2, the inhibitory effect of SO2 can be obviously weakened. The results of XRD, XPS and temperature programmed desorption experiments (TPD) indicate that the active components MnOx disperse well on the surface of PG. The removal process of Hg0 on the MnOx/PG catalyst includes the steps of adsorption, oxidation and reaction, and HgO and HgSO4 are generated and adsorbed on the catalyst.

     

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