In this work, a functionalized mesoporous carbon (CMK-3-O) was synthesized after oxidation with nitric acid and was used to adsorb dibenzothiophene (DBT) from model oil for the first time. Then, its performance was compared with that of CMK-3. The functionalized mesoporous carbon, CMK-3-O, showed better a capacitance performance for DBT adsorption than that of CMK-3. The maximum adsorption capacity was obtained for functionalized mesoporous carbon at optimum conditions with 6 M HNO3 aqueous solution and 30 min contact time. The physical and structural properties of CMK-3-O and CMK-3 were investigated with X-ray diffraction method (XRD), N-2 adsorption-desorption isotherm, FT-IR, and elemental analysis (CHNO). Results of the elemental analysis showed that the oxygen and nitrogen content has increased and the carbon content has decreased through oxidation treatment. The effects of various factors on the adsorption process (such as temperature, amount of adsorbent, contact time, and concentration) of DBT were studied. CMK-3-O showed a maximum adsorption capacity of 86.96 mg DBT g(-1) of CMK-3-O at optimized conditions (temperature, 25 degrees C; adsorbent dosage, 20 g L-1; contact time, 60 min), which was a higher adsorption capacity of that observed for CMK-3 (57.47 mg DBT g(-1) of CMK-3). Kinetic studies have revealed that the adsorption of DBT can be described by a pseudo-se%cond-order rate equation. Equilibrium data showed that adsorption process was best represented by the Langmuir model. The results also illustrated the fact that the regenerated adsorbent afforded 64.3 of the initial adsorption capacity after the two regeneration cycles.