Development of Coconut Shell Activated Carbon with Sulfur Impregnation for Vapor Phase Mercury Removal

In order to develop highly efficient but low-cost adsorbents for mercury control, coconut shell was chosen to prepare activated carbon, which was then impregnated with elemental sulfur at 400-800 degrees C for modification. Experimental studies on Hg-0 removal were investigated in a fixed bed reactor system. Coconut shell activated carbon impregnated with elemental sulfur at 500 degrees C exhibited better mercury adsorption capacity than commonly used activated carbon with high sulfur content. Factors including porous structure, sulfur content, and sulfur forms on adsorbent were all important for Hg-0 adsorption. Elevating the impregnation temperature decreased the total sulfur content, while optimizing the pore structure parameters. Elemental sulfur, thiophene, and sulfate were the main forms of sulfur deposited on the carbon surface promoting the Hg-0 adsorption capacity. Among them, elemental sulfur was the most effective.