Carbon dioxide adsorption by amine-functionalized Silicalite-1 zeolite: Impact of amination on surface properties and adsorption efficiency

Abstract

CO2 is present as an impurity in natural gas, flue gas, syngas, biogas, and several other gas streams emitted from industrial processes. To improve the quality of natural gas, syngas, and biogas, and to mitigate the greenhouse effect of CO2 on the environment, the removal of CO2 from such gas streams is of paramount importance. Crystalline microporous materials are promising for the adsorption of CO2 owing to their high surface area and tuneable pore size, making them effective for CO2 adsorption. In this work, we prepared Silicalite-1 material and functionalized it with amine groups by impregnation method. Comprehensive characterization using X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) was performed. Amination process reduced the surface area and porosity of Silicalite-1; however, it substantially increased the Silicalite-1 affinity for CO2 adsorption by several magnitudes. Comparative analysis with literature data shows a consistent trend of decreased BET surface area and porosity following amination across various zeolite types, accompanied by a corresponding reduction in CO2 adsorption capacity in mmol/g. These findings highlight the importance of balancing surface area reduction and adsorption affinity in designing functionalized zeolites for CO2 capture applications.

Keywords

• Air pollution
• Chemical processes
• CO2 capture
• Porous materials
• Sustainable processes