Enhancing cyclic stability and anti-sintering capacity of CaCO3-MgO sorbents for CO2 capture

Abstract

CaCO₃-MgO sorbents were prepared through mechanochemical methods to overcome the poor stability of MgO sorbents caused by sintering and agglomeration. The alkali metal salt-promoted MgCa5 (AMS-MgCa5) sorbent, with 5 wt% CaCO₃ doping, demonstrated the highest cycling stability, with an initial CO₂ capture capacity of 13.9 mmol/g, which stabilized at 9 mmol/g after 10 cycles, and the CO₂ capture ratio reached 77 %. The superior cycling stability of the sorbents was attributed to the existence of CaMg(CO₃)₂, which enhanced the capture rate during the CO₂ chemisorption process. Additionally, the doped CaCO₃ served as an inert support, enhancing CO₂ diffusion and mass transfer, ensuring the uniform coverage of alkali metal salt on the MgO surface, and inhibiting the growth of MgO particles.