AMINE-GRAFTED MESOPOROUS SILICA FOR CO2 CAPTURE

Abstract

Three-aminopropyltriethoxysilane modified MCM-41 mesoporous silicas were synthesized by grafting the organic groups on the support surface, using different molar ratios of SiO2: Aminosilane. The synthesized solids were characterized by N2 adsorption, XRD, FTIR and TG-DTA. MCM-41 has a specific surface area of about 1500 m2/g, while that of the functionalized materials falls around 600 m2/g, showing a tendency to decrease as the content of the functionalizing agent grows. The N2 adsorption isotherms of pure and functionalized materials are characteristic of mesoporous type IV materials. The structural properties were studied by FTIR and XRD. TG-DTA studies allow analyzing the thermal stability of the materials and determining the deposited amine content. The aminosilane modified mesoporous silica materials increase the CO2 adsorption capacity compared to that of the pure support. Freundlich, Dual Sites Sips and Dubinin-Radushkevich equation models, all explained data satisfactorily. Further analysis using Freundlich equation revealed that the model parameters showed linear correlation with APTES molar content in the samples.