Kinetics and Mechanism of Chemical Reaction of CO 2 and Ba 2 Fe 2 O 5 Under Various CO 2 Partial Pressures

The reaction kinetics of the CO 2 absorption by Ba 2 Fe 2 O 5 , which shows a reversible reaction with CO 2 represented as Ba 2 Fe 2 O 5 + CO 2 ⇄ Ba CO 3 + Ba Fe 2 O 4 , was investigated by thermogravimetry under various CO 2 partial pressures [ P ( CO 2 )s]. The calculated Ellingham diagram of the reaction was found to show agreement with the variation in the equilibrium temperature of the reaction with P ( CO 2 ). The results of the morphology observation, specific surface area analysis, and TG measurement suggested that the CO 2 absorption mechanism of Ba 2 Fe 2 O 5 is described by a superficial reaction, a diffusion‐controlled process, and a sintering reaction as the reaction proceeds. The kinetics of CO 2 absorption for the diffusion‐controlled process has been analyzed with the Jander function, showing that the activation enthalpy was about 1.6 × 10 2 kJ/mol.