Mechanism sorption of carbon dioxide onto dam silt

Abstract In this paper, a study of the adsorption of carbon dioxide onto raw Chorfa silt material (Mascara, Algeria) was experimentally investigated using volumetric technique at 295 K and at a pressure range from 15.59 to 750 mm Hg. XRD, MEB, and BET analysis were used to characterize the adsorbent. This material consisted of calcite and illite as main components. Several models were used to describe the experimental isotherm such as Langmuir, Freundlich, Hill De Boer, and Sips. The best fit of adsorption isotherm data is obtained with the Sips model. The proposed methodology for the analysis of the experimental adsorption data allows the determination of the micropore volume (V0) and the characteristic energy (E) using Dubinin–Raduskevich equation. An experimental value of V0 equal to 0.875 cm3/g is obtained in very good agreement with those found using the “t-plot” method, it is equal to 0.920 cm3/g. The characteristic energy E is equal to 20.9 kJ/mol, this value indicates that the adsorption is of physical type. The unipore diffusion model was selected for sorption kinetic modeling. The diffusion process of CO2 in the silt is slow. A thermodynamic study showed spontaneous nature and feasibility of the adsorption process.