(248x) Carbon Dioxide Capture on Amine Modified MCM-36

Solid adsorbents are currently being investigated as replacements for liquid amine systems for the capture of carbon dioxide in industry. However, they are generally unable to match the carbon dioxide selectivity and capacity of liquid amine systems. In order to address this difficulty, many researchers have looked into the impregnation or covalent bonding of amine molecules onto a high surface area solid support, such as zeolites or nanostructured silicas. Our work has been on the investigation of the use of the amine-impregnation method on the layered MCM-36 structure, in order to determine if an optimal capture capacity can be achieved. MCM-36 is composed of microporous layers, stacked in a lamellar fashion, and contains both microporous channels accessible to CO2 and larger pore channels between each layer. It is possible to selectively functionalize the larger pore channels with PEI, because the amine is too large to enter the microporous layers. This creates a material with open diffusion channels for carbon dioxide as well as an amine functionalized zone between the layers. It was found that with increasing amine content, the diffusion properties and capture capacity was greatly reduced. Data suggests that amine loading eventually blocks the porous channels in MCM-36, leading to an upper limit in the capacity of the support which is far lower than that in the initial bare material. Our work shows that amine impregnation cannot further improve MCM-36 as a capture system.