Clinoptilolite and MCM-41 impregnated with chitosan as a green novel adsorbent for CO2 capture

Abstract

The Clinoptilolite and Mobil Composition of Matter No. 41 (MCM-41), represented by natural inorganic and synthetic inorganic materials, respectively, were supported by chitosan and used as solid adsorbents for CO2 capture. Studying different parameters like temperature and pressure revealed that the highest adsorption capacities were observed at 25 ᵒC and 9 bar with values of 8.90 mmol/g for MCM-41@Chitosan and 9.01 mmol/g for Clinoptilolite@Chitosan. According to the isotherm study results, when Clinoptilolite@Chitosan was used as a solid adsorbent, the experimental results best fit both the Langmuir model and Freundlich model. For MCM-41@Chitosan, the Sips model exhibited the highest R2 value. The results of the Kinetic study demonstrated that the CO2 capture by MCM-41@Chitosan and Clinoptilolite@Chitosan involved physisorption, best aligned with the Elovich model described the CO2 adsorption process Furthermore, the thermodynamic study of both adsorbents indicated that as the temperature increased, the highest adsorption capacity decreased. Therefore, the CO2 capture process by both solid adsorbents was exothermic. The mass transfer parameters of Clinoptilolite@Chitosan and MCM-41@Chitosan were determined within a single-component system. Clinoptilolite@Chitosan exhibited a mass flux of 0.3488 mol/m2.s, a diffusion coefficient of 3.07 × 10−4 m2/s, and a mass transfer coefficient for CO2 molecules in the gas phase of 9.790 m/s. Meanwhile, MCM-41@Chitosan demonstrated a mass flux of 1.41 × 10−4 mol/m2.s, diffusion coefficient of 0.1517 m2/s and mass transfer coefficient of 0.1661 m/s.

Keywords

• CO2 capture
• Composite adsorbents
• Mass transfer
• Clinoptilolite
• MCM-41
• Chitosan