Textural properties determined CO2 capture of tetraethylenepentamine loaded SiO2 nanowires from α-sepiolite

To understand the effect of porous parameters and chemical components on CO2 capturing performance of solid state amine absorbents and their kinetic parameters, a clay mineral-based CO2 absorbent was prepared by impregnating five different liquid amines onto SiO2 nanowire clusters from fibrous sepiolite (Sep). Characterization was conducted by XRD, SEM, FTIR, and N-2 adsorption-desorption isotherm, CO2 adsorption performances were measured by TGA. After acid treatment, the raw Sep mineral changed into amorphous silica nanowires, and the largest S-BET of the obtained SiO2 nanowires reached 320 m(2)/g, which was 8 times larger than the pristine mineral. Amongst the adapted amines, tetraethylenepentamine (TEPA) showed superiority in the CO2 adsorption capacity. The optimized adsorption capacity reached 3.7 mmol/g at 75 degrees C from a CO2 + N-2 mixture on a similar to 50 wt % TEPA loaded SiO2 sample, and the capacity remained 3.6 mmol/g after ten circles of adsorption/desorption tests. The pore size and pore structure of the matrix, rather than the surface area, will obviously affect the adsorption ability of the product. Kinetic parameters for the CO2 adsorption process fitted well with a fractional-order model, confirming that the CO2 adsorption process by the solid absorbent should be a combination of both physical and chemical reactions. Results in this article provide detailed parameters for preparing and understanding these clay mineral based solid state CO2 absorbents.