Improvements of CaO-based sorbents for cyclic CO2 capture using a wet mixing process

CaO-based sorbents are suitable candidates for CO2 capture at high temperatures. However, the CO2 capture capacity of untreated CaO-based sorbents decreases sharply after a few cycles. In this paper, a wet mixing method was employed to synthesize CaO-molecular sieve-alumina ceramic sorbents for CO2 capture. Cyclic experiments were carried out in a thermogravimetric analyzer (TGA). The sorbent using molecular sieve and alumina ceramic as the calcium precursors showed the best cyclic CO2 uptake capacity, 0.41 g CO2/g sorbent after 20 cycles of calcination and carbonation. The synthesized materials were characterized by X-ray diffraction (XRD), nitrogen adsorption and desorption isotherms test, and scanning electron microscopy (SEM)/energy dispersive spectrometer (EDS). The sorbent showed a better sintering-resistant property and a more porous microstructure during multiple calcination and carbonation cycles.