Kinetic study of CO₂ adsorption of granular-type activated carbons prepared from palm shells

The adsorption kinetics of activated carbon (AC)-type adsorbent materials, which were prepared from a by-product of African palm (shells) processing by chemical activation with dehydrating metal salts at two different concentrations, was studied. N₂ physisorption was performed in order to determine the textural characteristics of the adsorbent solids, obtaining materials with BET areas between 721 and 1334 m²g^-1 and micropore volumes between 0.33 and 0.55 cm³g^-1; FTIR determination was also used as a chemical characterization technique in order to observe variations in the functional groups present. CO₂ adsorption was determined, obtaining values between 175 and 274 mg∙g^-1; these results are correlated with the physicochemical characteristics of the materials. With the experimental data obtained in this adsorption, the kinetic study was carried out taking into account the kinetic models of pseudo-first-order, pseudo-second-order, and intraparticle diffusion, showing a better adjustment to this last model of a physisorption process. Finally, CO₂ adsorption calorimetry was performed on the two adsorbents that presented the highest adsorption capacities, evidencing variations in the characteristics of the activated carbons with the change of the impregnant used. A correlation is observed between the speed of the CO₂ adsorption process and the adsorption capacity.