For the expansion of utilization of petroleum coke (petcoke), activated carbon (AC) was prepared from petcoke with potassium hydroxide (KOH) chemical activation, and pore structure and surface chemistry of the prepared AC were investigated. Moreover, adsorption behavior of ammonia (NH3) and hydrogen sulfide (H2S) on activated carbon prepared was studied. The specific surface area of AC increased with increasing activation temperature, meanwhile the acidic surface functional groups decreased. Pore-structure development was basically promoted with an increase in the KOH/petcoke weight ratio. Ammonia adsorption was found to proceed rapidly even at 303 K, and the amount of NH3 adsorbed was dependent on the surface acidic functionalities, especially for hydroxyl and carboxyl groups on AC surface. On the other hand, hydrogen sulfide adsorption test conducted at room temperature showed that adsorption of H2S proceeded with very slow rate, and the adsorption capacity of H2S was correlated with the pore characteristics of ACs, especially with the micropore surface area. (C) 2015 Elsevier B.V. All rights reserved.