Activated carbon adsorbents have been evaluated at high pressure, up to 4 MPa, to determine their applicability for the removal of CO2 from syngas generated from gasification. The CO2 adsorption capacity and diffusion mechanism were demonstrated to be dependent upon the adsorbent outgas conditions. Activated carbons have been demonstrated to have higher adsorption capacities than existing absorption systems up to 12 mmol g?1 at 4 MPa, under strong outgas conditions. Adsorption capacities on a weight basis have been demonstrated to be correlated with the surface area and micropore volume of the materials. However, performance on a volumetric basis is less well-defined and is controlled by the form and bulk density of the adsorbent. Complete cyclic regeneration of the adsorbents has been demonstrated by pressure swing regeneration cycles.