CO2 capture on amine impregnated mesoporous alumina-silica mixed oxide spheres

Spherical alumina-silica mixed oxide supports with hierarchical mesoporous structure were prepared by drip cast method using organic mesomorphous complexes of a cationic surfactant (CTAB). The microstructural properties of supports were greatly influenced by the Si/AI ratio and CTAB. The support with Si/AI ratio 5:1 shows the highest specific surface area, pore volume and a pore diameter of 11 nm. Supports were infiltrated with diethanolamine (DEA) by wet impregnation. The CO2 sorption is revealed from the detection of characteristic IR peaks of carbamate species. Carbon dioxide sorption and regeneration tests on the prepared sorbents have been performed using a laboratory scale plant equipped with a fixed-bed tubular unit operating in continuous flow mode. Maximum CO2 sorption capacity of 40 mg/g sorbent was achieved for sorbents with Si/AI ratio 5:1 and 36 wt% of DEA loading. The effect of different DEA loading on support revealed that by increasing the amount of DEA >36 wt%, there is a decrease in the CO2 sorption capacity of the sorbent. The lower CO2 capture capacity at higher amine content is attributed to the occlusion of mesopores with DEA molecules, which was evident from SEM analysis and N-2 adsorption/desorption analysis. (C) 2017 Elsevier B.V. All rights reserved.