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

Abstract 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 /Al ratio and CTAB. The support with Si/Al 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 CO 2 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 CO 2 sorption capacity of 40 mg/g sorbent was achieved for sorbents with Si/Al 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 CO 2 sorption capacity of the sorbent. The lower CO 2 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.