Investigation on a novel CaO–Y2O3 sorbent for efficient CO2 mitigation

Abstract Different amounts of Y 2 O 3 were incorporated into CaO through a sol–gel combustion method and compared with two naturally occurring sorbent and CaO derived from calcium acetate on CO 2 capture performance. XRD, SEM, TEM and N 2 adsorption results revealed that homogeneously dispersed Y 2 O 3 nanoparticles notably improved the sorbent morphology, and therefore the capture performance. The carbonation rate in the fast stage was greatly enhanced via Y 2 O 3 addition and a linear relationship was established between the maximum carbonation rate and the volume of pores with diameters less than 220 nm. The sorbent containing 20 wt% Y 2 O 3 presented excellent cyclic CO 2 capture capacity as well as stability. After 10 cycles it absorbed 0.57 g CO 2 /g sorbent under mild conditions and still 0.49 g CO 2 /g sorbent under realistic conditions, respectively. Finally, calcination conditions significantly influenced the sorption performance and sorbent structure. Combined with pore size distribution measurement, enhanced sintering and reactivation, two counteractive roles brought by CO 2 addition during calcination, were elucidated.