Abstract Activated carbons are obtained by chemical activation of African Palm shells ( Elaeis guineensis ) with different impregnating agents, i. e. magnesium chloride (MgCl 2 ) and calcium chloride (CaCl 2 ) aqueous solutions at different concentrations (3, 5 and 7 % w/v) and temperatures (between 773 and 1073 K), in order to assess their influence on the development of the porosity. The activated carbons prepared are characterized in terms of both textural and chemical properties. The activated carbons have a surface area and a pore volume ranging between 19 and 501 m 2 .g −1 and 0.03–0.29 cm 3 .g −1 , respectively. Based on the obtained results, the samples with higher surface area and pore volume (i. e. those impregnated with MgCl 2 and CaCl 2 solutions and thermally treated at 1073 K) are selected to evaluate the adsorption capacity and affinity for CO 2 . CO 2 adsorption capacity varies between 1.78 and 2.95 mmolCO 2 .g −1 at 273 K and low pressure, and the activated carbon impregnated with the solution of MgCl 2 3% and activated at 1073 K (i. e. ACMg3-1073) showed the best performances. Finally, the kinetic results show that adsorption rate for sample ACMg3-1073 is enhanced by its micro-mesoporous nature, being the access routes to the micropores larger.