evaluation of the silica gel adsorbent potential for carbon dioxide capture: experimental and modeling

In this research, silica gel as a low-cost adsorbent for the uptake of carbon dioxide was investigated experimentally. the samples were characterized by xrd, bet and ft-ir. it shows that as pressure was increased from 2 to 8 bar, the co2 adsorption capability improved over time. at a pressure of 6 bar and a dose of 1 g of silica gel, the impact of temperature (25, 45, 65, and 85 °c) on the co2 adsorption capacity (mg/g) was determined. the process behavior was investigated using isotherm, kinetics and thermodynamic models. as the temperature rises at a constant pressure, the adsorption capacity decreases. the experimental data of the carbon dioxide adsorption using silica gel have a high correlation coefficient with both langmuir (0.998) and freundlich (0.999) models. the results of the carbon dioxide adsorption kinetics with the silica gel adsorbent show that the correlation coefficient (r2) of the second-order model and ritchie's second model are equal to 0.995 and have the highest value. the total pore volume was 0.005119 (cm3 g-1) and the specific surface area was 2.1723 (m2g−1). the maximum co2 adsorption capacity at 25 °c near 8 bar was 195.8 mg/g.