Removal of elemental mercury from gas stream using sulfur-functionalized silica microspheres (S-SMs)

Abstract

Silica microspheres (SMs) was synthesized and modified through impregnation with elemental sulfur (S8) and carbon disulfide (CS2) to produce sulfur-functionalized silica microspheres (S-SMs). The morphology of SMs did not change after modification, however, its pore characteristics and sulfur content as expected did change significantly. The elemental mercury adsorption rate and capacity from synthetic gas stream increased with the presence of sulfur compounds in the SMs. For instance, at bed temperature of 50 °C, the adsorption capacity and rate of adsorbents (SMs, S8-SMs and CS2-SMs) were (5.71, 37.24, and 83.41 µg/g) and (0.319, 0.749, and 1.922 µg Hg°/g min), respectively. It was observed that the adsorption rate and the capacity increased with bed temperature only for the SMs, while decreasing for the S-SMs. This might be due to different governing adsorption mechanisms for both types of adsorbents.