Adsorption of CO2 on mesocellular siliceous foam iteratively functionalized with dendrimers

Melamine-type dendrimers are grafted to mesocellular siliceous foam (MCF) with ultralarge mesopores by stepwise alternating treatments of the substrate with 2,4,6-trichlorotriazine and ethylenediamine. MCF grafted dendrimers up to 4th generation are prepared and characterized. Very high organic loadings (55 wt% at the 4th generation) are achieved, with half of the initial substrate mesopores volume remaining unoccupied-leaving room for the rapid ingress and egress of small gas molecules. The product materials possess relatively high thermal stability-their decomposition starts at around 300 A degrees C. Adsorption measurements suggest that only the primary amine groups of these melamine type structures are active for CO2 chemisorption. The CO2 adsorption capacities of these adsorbents are improved relative to the unfunctionalized MCF, especially when considered on a wt% substrate basis.