Grafting Morphologies of TEPA on SBA-15(P) and Its Effect on CO2 Adsorption Performance

Various amine-functionalized CO2 adsorbents were prepared by incorporating tetraethylene-penthamine (TEPA) onto SBA-15(P) by controlling the impregnation method and its process. The materials were characterized using X-ray diffraction (XRD), N-2-adsorption, elemental analysis, and Fourier transform infrared (FTIR) techniques. Their adsorptive capacities were determined by CO2-temperature programmed desorption (TPD). The results indicate that the dynamic impregnation process using a TEPA ethanol solution was successful in loading TEPA into the channels of SBA-15(P). Moreover, bonding formation between the highly dispersed TEPA and SBA-15(P) was facilitated to CO2 adsorption/desorption. Therefore, a binding mechanism is proposed. The -NH2 group of TEPA forms hydrogen bonds with -OH and C-O-C groups on SBA-15(P), which results in the better dispersion of TEPA. However, the dynamic impregnation process for the TEPA ethanol solution can effectively avoid the formation of hydrogen bonds between the intra- and inter-molecules resulting in the high adsorptive capacity of the amino groups in TEPA.