Intrinsic Kinetics of Platy Hydrated Magnesium Silicate (Talc) for Geological CO2 Sequestration: Determination of Activation Barrier

Abstract

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.