Activated carbon (AC) was prepared from hazelnut shells using two steps of carbonization followed by steam activation. Methylene blue dye was used as a probe for evaluation of the prepared activated carbon. In order to have a better comparison, a commercial grade of activated carbon (powdered) obtained from the Merck Company has also been used in this research as standard. In this paper we have also investigated adsorption of mercuric ion by impregnated activated carbon with different chemicals. It was found that sorption of mercuric ion from aqueous solution by activated carbon can be improved by impregnating AC with suitable chemicals such as sulfur-containing compounds.