Investigation of the CO₂ adsorption isotherms on activated carbon by statistical physics treatment

The aim of this paper was to study CO₂ adsorption on the activated carbon (AC) prepared from olive waste. The AC was characterized via X-ray diffraction, Scanning Electron Microscopy (SEM) and N₂ adsorption-desorption. The adsorption isotherms were measured at various temperatures, namely, 298 K, 308 K, and 318 K. Based on the experimental result, a new model was generated and evaluated by means of a multilayer model with saturation. The physicochemical properties that characterize the CO₂ adsorption mechanism have been established using a physical statistical approach. The parameters which characterize the CO₂ adsorption isotherm, such as the number of carbon dioxide molecules per site (n), the receptor site densities [Formula: see text], and the energetic parameters (ΔE₁, ΔE₂) were studied. In addition, thermodynamic functions such as internal energy (E_int) and Gibbs free energy (G), were established using a physics model. Thus, the obtained results indicated that the CO₂ adsorption on the AC was exothermic and physisorption in nature. Furthermore, the results achieved with this model can be used to design and optimize an adsorption unit for CO₂ capture.