CO2 capture by the amine-modified mesoporous materials

Novel CO, adsorbents were prepared by grafting of two different aminosilanes on mesoporous silica MCM-41 and SBA-15. The properties of the mesoporous materials before and after surface modification were investigated by powder X-ray diffraction (XRD) pattern, solid-state Si-29 nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectra, and measurements of N-2 adsorption and desorption isothermal, which confirmed that ammosilanes were grafted on the surface of the channels in the mesoporous materials. Thermogravimetry analysis (TGA) evaluated the amounts of grafted amine to be about 1.5-2.9 mmol . g(-1). The CO2 adsorption capacities of MCM-41 increased from 0.67 mmol . g(-1) to 2.20 mmol . g(-1) after AEAPMDS (N-beta-(aminoethyl)-gamma-aminopropyl dimethoxy methylsilane) modification (p =101 kPa) at room temperature. The studies of the mechanism of CO, adsorption suggested that there were two main contributions for the increase: the chemical adsorption based on the active sites of amine groups and the capillary condensation caused by the nano-scale channels of the mesoporous materials.