Effect of Varying Amine Functionalities on CO2 Capture of Carboxylated Graphene Oxide-Based Cryogels.

Graphene cryogels synthesis is reported by amine modification of carboxylated graphene oxide via aqueous carbodiimide chemistry. The effect of the amine type on the formation of the cryogels and their properties is presented. In this respect, ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), were selected. The obtained cryogels were characterized by Fourier Transformed Infrared spectroscopy, thermogravimetric analysis, X-ray spectroscopy, and Scanning electron microscopy. The CO2 adsorption performance was evaluated as a function of amine modification. The results showed the best CO2 adsorption performance was exhibited by ethylenediamine modified aerogel, reaching 2 mmol g-1 at 1 bar and 298 K. While the total N content of the cryogels increased with increasing amine groups, the nitrogen configuration and contributions were determined to have more important influence on the adsorption properties. It is also revealed that the residual oxygen functionalities in the obtained cryogels represent another paramount factor to take into account for improving the CO2 capture properties of amine-modified graphene oxide (GO)-based cryogels.