| Summary: | MCM-41 and SBA-15 were chosen as nanoporous materials based on silica for its modification with amine groups. This modification was done by two methods: grafting method and wet impregnation method. The first method grafted-amine groups by chemical reaction between surface silanol groups in the nanoporous materials and 3-aminopropyltrimetoxilane (APTMS).In the wet impregnation method, low molecular weight polyethylenimine (PEI) is incorporated trough this method. These modified materials capture CO2 at low temperature. CO2 capture on the sorption sites by amine loading is believed to occur via chemisorption mechanism by formation of ammonium carbamate. The evaluation and analysis of CO2 adsorption was carried out by two methods: static mode and dynamic mode. The static mode is a pure CO2 adsorption-desorption isotherms at 298K. The isotherms of the functionalized materials show a behavior by chemisorption, capture at low pressure, being the desorption branch almost horizontal, while nanoporous silica isotherms is due a physical adsorption, low CO2 capture at low pressure and dependence with pressure, a complete reversibility of the desorption process. The dynamic mode is a thermogravimetry study at different N2/CO2 concentrations. Isothermal CO2 captures at 298K were carried out to evaluate the suitability of the samples for cyclic operation. The mass increase during the capture step was interpreted as CO2 adsorption capacity of the samples. The results obtained by both methods were compared, and, its differences were analyzed.
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