Two activated carbons have been prepared by chemical activation of deinking paper sludge with K2CO3, with further carbonization in N-2 (AC-N-2) or CO2 (AC-CO2) and characterized in terms of proximate analyses, adsorption/desorption of N-2, skeletal and bulk pycnometry, acid/base and Boehms titrations, X-ray diffraction and scanning electron microscopyenergy dispersive spectroscopy (SEM-EDS) analyses. A commercial activated carbon (AC-COM) was subjected to the same characterization program for comparison purposes. Surface area/porosity followed the trend: AC-CO2 < AC-N-2 < AC-COM, revealing a good development of porosity in samples prepared in the laboratory but not approaching that of the commercial sample. Surface basicity, in turn, followed the trend: AC-CO2 > AC-N-2 >> AC-COM, due to the presence of CaCO3, which is a basic salt, in the carbons prepared. The three adsorbents were tested in the adsorption of SO2, where a proper selection of carbon particle size that maximized pore diffusion control led to a higher SO2 uptake. Adsorption equilibrium was successfully fitted to Langmuir and Freundlich isotherms. Final adsorption capacity was governed by textural properties, while adsorption affinity was influenced by both surface basicity and porosity.