Abstract
In this study, activated carbons were prepared and tested as CO2 adsorbents at a temperature of 273 K and at atmospheric pressure. African palm stone was used as the precursor material, which was initially impregnated with CaCl2 solutions at different concentrations. The textural characterization of activated carbons was performed by nitrogen adsorption at 77 K. The energetic parameters were determined by immersion calorimetry in benzene and water. In addition, the total acidity and basicity were estimated using Boehm titrations. A maximum surface area of 1700 m2 g−1 was obtained with a pore volume of 0.64 cm3 g−1. Immersion calorimetry provided results between −17.95 and −95.75 J g−1 in benzene and between −13.63 and −30.24 J g−1 in water. The materials had a maximum CO2 adsorption capacity of 5.75 mmol CO2 g−1. It was found that the adsorption of gas increased with the total basicity and decreased with acidity. Finally, correlations were established between the textural characteristics, determined by gas adsorption and the immersion enthalpy data.