Preparation of Carbonaceous Heavy Metal Adsorbent from Coal Using Sulfur Impregnation

We attempted to prepare sulfur-impregnated adsorbent from coal for removal of heavy metals. A two-step process (pyrolysis and sulfur impregnation) was used. Raw coal was rapidly pyrolyzed to prepare char with a high specific surface area. It was sulfurized by H2S impregnation to obtain sulfur-impregnated char that could adsorb heavy metals. Pyrolysis char with high specific surface area can be obtained by rapid pyrolysis; sulfur can be added to rapid-pyrolysis char using H2 gas. Sulfur-impregnated char was more effective for adsorption of Pb2+, Cd2+, and Zn2+ than raw coal, rapid-pyrolysis char, and commercial charcoal.