Evaluation of CaO derived from Cerastoderma glaucum of Caspian beach as a natural sorbent for CO2 capture

In this work, Cerastoderma Glaucum (CG) as a bio-sorbent, a low-cost, and nontoxic material, was investigated for CO₂ capture. The analysis of CaO from CG was carried out using X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR), a scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX) and N₂ adsorption-desorption isotherm. The total pore volume was 0.0055 ​cm³/g, and the specific surface area (S_BET) was 1.9312 ​m²/g (BET: Brunauer–Emmett–Teller). The maximum CO₂ adsorption capacity reached 0.48 ​mmol/g at 25 ​°C and 4.5 ​bar. The CO₂ adsorption capacity was examined as a function of pressure. In the experiments, it was discovered that adsorption capacity increased with increasing pressure. As a second step, the isotherm models were used to determine how the adsorbent behaves. Hill, Freundlich, Koble–Corrigan, and Sips isotherm models are well correlated with the adsorption data experiments.