Carbon Black granules were modified in a rotating RF (13.56 MHz) plasma reactor fed with NH3/O2 gas mixtures, in order to graft acid (O‐containing) and/or basic (N‐containing) chemical groups and tune their surface acid/base character. X‐rays photoelectron spectroscopy was used to evaluate the surface chemical composition of the modified carbon surface. Boehm titrations, in OH−/H+ water solutions, and NH3/HCl vapour adsorption tests were performed on plasma treated Carbon Black, with the aim to check its capability of adsorbing acid and basic compounds from solution and in gas/vapour phase, respectively.