Removal of methyl mercaptan was investigated using adsorption on virgin activated carbon (VAC) and modified activated carbons with acidic chemicals in the present work. CAC, NAC, AAC and SAC were represented as activated carbons modified with HCI, HNO$_{3}$, CH$_{3}$COOH and H$_{2}$S0$_{4}$ ,respectively The pore structures were evaluated using nitrogen isotherm. The surface properties of virgin activated carbon and modified activated carbons were characterized by EA, pH of carbon surface and acid value from Boehm titration. The modification of activated carbon with acidic chemicals resulted in a decrease in BET surface area, micropore volume and surface pH, but an increase in acid value. The order of the adsorption capacity of activated carbons was NAC>AAC>SAC>CAC>VAC, and in agreement with that of acid value of activated carbons, whereas in disagreement with that of micropore volume of activated carbons. It appeared that chemical adsorption played an important role in methyl mercaptan on modified activated carbons with acidic chemicals compared to virgin activated carbon. Modifying activated carbon with acidic chemicals enabled to significantly enhance removal of methyl mercaptan.