Pd/Al2O3 Sorbents for Elemental Mercury Capture at High Temperatures in Syngas

To capture elemental mercury (Hg-0) at high temperatures in simulated syngas, Pd/Al2O3 sorbents were developed using an impregnation method. The Pd/Al2O3 sorbents with a Pd loading value of 8% exhibited high Hg-0 capture activity from 200 to 270 degrees C. Over 90% of the mercury capture by 8Pd/Al2O3 was achieved for operating temperatures up to 270 degrees C. The superior performance of Pd/Al2O3 sorbents could be primarily ascribed to the formation of a Pd-Hg amalgam. H-2 and CO were found to be promotional on Hg-0 capture because of the reduction of PdO to Pd metal. H2S significantly inhibited Hg-0 capture due to the consumption of the active palladium. HCl promoted Hg-0 capture, which could be ascribed to the catalytic oxidation of Hg-0 to HgCl2. H2O showed a prohibitive effect on Hg-0 removal. The regeneration experiments indicated that the spent Pd/Al2O3 sorbents could be facilely revivified and reused.