The pore structure and surface chemistry of commercial activated carbon were modified by microwave heating at 600 degrees C, 700 degrees C, and 800 degrees C and chemical treatment with NaOH, Na2CO3, and NaHCO3. The pore structures of the modified adsorbents were characterized by nitrogen adsorption/desorption; whereas, the surface functional groups were determined by Fourier transform infrared spectroscopy and Boehm titration. Furthermore, the effects of the microwave heating and chemical modification on the adsorption of acetone were investigated experimentally. The adsorption process was studied based on the adsorption equilibrium and adsorption energy of the adsorbents. The results indicate that the amount of acidic surface functional groups decreased; whereas, the amount of basic surface functional groups increased after the chemical and microwave heating treatments. Moreover, the microwave heating treatment was more effective than the chemical treatments for optimizing the pore structure of the activated carbon. The micropore volume showed good linear correlation with the adsorption capacity; whereas, the adsorption energy reflected that the adsorption of acetone on the ACs was mostly physical adsorption. The adsorption of acetone on ACs was better described by the Langmuir equation than the Freundlich equation.