CO 2 adsorption by PAMAM dendrimers: Significant effect of impregnation into SBA-15

Adsorption capacities for dry CO 2 were determined for neat polyamidoamine (PAMAM) dendrimers (generation G0.0, 1.0, 2.0 and 3.0), mesoporous SBA-15 and impregnated adsorbents (50% by weight) consisting of SBA-15 as substrate and PAMAM dendrimer (G0.0, 1.0, 2.0 and 3.0) at 20, 75 and 105 °C. Neat PAMAM dendrimers adsorbed CO 2 very poorly. However, impregnation by these materials into SBA-15 improved their CO 2 adsorption capacity significantly, especially at 75 and 105 °C. Impregnation seems to break down internal H-bonding and allow the amine groups within the dendrimer to interact with CO 2. Elevated temperature improves CO 2 diffusion within the impregnated adsorbents, presumably due to improved mobility of the dendrimers, such that cyclic adsorption/desorption behaviour would be realised on a reasonable (10 min) time scale.