MIL-100(Fe) supported Mn-based catalyst and its behavior in Hg° removal from flue gas

摘要

A novel magnetic composite catalyst of MnOx loaded on MIL-100(Fe) was prepared for the removal of Hg-0 from flue gas, via incipient wetness impregnation followed with calcination at 300 degrees C. The MIL-100(Fe) supported catalyst showed greater capacity of Hg-0 adsorption and oxidation than Fe2O3 supported catalyst at all test temperatures, showing Hg-0 removal efficiency of 77.4% at 250 degrees C with high GHSV of 18,000 h(-1). Besides the merit of high BET surface area and developed porous, the ultra-highly dispersed and homogeneous Fe sites on MIL(Fe) significantly promoted Hg-0 adsorption and oxidation via the synergy effect with MnOx. Furthermore, the catalyst exhibited magnetic property, which allowed easy separation of the catalyst from fly ash with a recovery of 104%. SO2, H2O and NH3 in flue gas were proved inhibited Hg-0 removal via different mechanisms. SO2 and H2O competed and desorbed Hg2+ on the surface of catalyst, while NH3 was more likely to compete adsorption sites with Hg-0.