Investigation of a stable synthetic sol–gel CaO sorbent for CO2 capture

In this study a synthetic calcium oxide sorbent was prepared using a sol–gel synthesis method. The synthesized CaO and a reference CaO, obtained through the calcination of commercial CaCO3, were characterized by means of X-ray diffraction, N2 adsorption and SEM microscopy. For the reference CaO, results from cyclic carbonation and calcination showed the typical behavior described in the literature. Conversely, the synthetic CaO, with a coral like morphology and higher surface area (45 m2/g), maintained its reactivity throughout 18 cycles, losing 55% over 70 consecutive cycles, with a residual reactivity value of 0.24 gCO2/gCaO. The morphology and structural changes of the synthesized CaO sample were examined and a deactivation mechanism was suggested.