Intrinsic kinetics of platy hydrated magnesium silicate (Talc) for geological CO₂ sequestration: Determination of activation barrier

Hydrated magnesium silicate (Mg₃Si₄O₁₀(OH)₂), commonly known as talc, is a direct carbonation agent. In this study, we investigated the utility of the carbonation reaction for CO₂ adsorption. To gain insight into talc carbonation, we performed CO₂ temperature-programmed-desorption and dynamic flow system experiments. Structural modifications proved that CO₂ adsorption occurred on the surface of the talc adsorbents to form carbonates. We achieved stable carbonation activities of talc by varying the temperature. In addition, the reaction kinetic model of talc carbonation based on the changes of CO₂ concentration was developed. From the observation that the activation energy of talc-based carbonation using the Arrhenius equation is 51.4 ± 4.8 kJ/mol, it is inferred that the chemical reaction is a rate-determining step for talc sequestration, based on relatively high activation energy.