One of the most important challenges in separation and purification processes is the efficient capture of carbon dioxide (CO2).1 Several materials have been developed for CO₂ capture, and their development requires an understanding of the role of pore size.2-3 This study presents a comparative investigation of the amination of two siliceous materials, silicalite-1 - a microporous material, and MCM-41, a mesoporous material - and their CO₂ adsorption capacities under identical conditions. Both materials were synthesized and functionalized with amines, followed by thorough characterization through X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA).
The results revealed that the amine-functionalized mesoporous silica material exhibited a slight decrease in BET surface area and CO₂ adsorption capacity, indicating some alteration in its structural integrity post-functionalization. Conversely, the microporous silica material experienced a significant reduction in both surface area and CO₂ adsorption capacity, suggesting that its smaller pore structure may be more sensitive to the functionalization process. Notably, both materials displayed increased CO₂ affinity following amination, with the microporous material showing a more pronounced enhancement. This pronounced increase in CO₂ affinity suggests that while the microporous material may lose overall capacity, its ability to selectively adsorb CO₂ is significantly improved.
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