Guanidinylated poly(allylamine) supported on mesoporous silica for CO sub(2) capture from flue gas

The CO sub(2) adsorption performance of aminosilica adsorbents prepared by the impregnation of poly(allylamine) (PAA) and guanidinylated poly(allylamine) (GPAA) into silica mesocellular foam supports is evaluated. The effect of amine loading on the CO sub(2) capacity is consistent with previous reports of poly(allylamine) impregnated adsorbents, whereby the capacity increases initially with increasing amine loading and then drops at very high amine loadings, due to restricted access to the amine sites at high loadings. The CO sub(2) capacity of the new GPAA impregnated adsorbents decreases with an increase in adsorption temperature, showing comparable capacities to those for PAA impregnated adsorbents at low to moderate temperatures. However, at adsorption temperature higher than 75 degree C, the CO sub(2) capacities of GPAA adsorbents are higher than those for PAA adsorbents, similar to 70% higher at the highest temperature studied, 140 degree C. CO sub(2) adsorption-desorption cycling experiments show that the GPAA adsorbents have a better stability and regenerability at higher temperatures, making this class of materials suited for temperature swing cycles operating in a higher temperature regime than traditional aminosilica adsorbents based on PEI.