Ab initio molecular dynamics study of ion-specific olivine dissolution with implications to CO₂ mineralization geosequestration

CO₂ mineralization is the safest CO₂ geosequestration method with the highest sequestration capacity. Even though there have been lab and pilot-scale demonstrations, the complex chemical reaction is still elusive at atomic level. Here, I show that the ab initio molecular dynamics (AIMD) and metadynamics simulations enable quantitative analysis of reaction pathways, thermodynamics, and kinetics of the Mg²⁺ and Ca²⁺ ion dissolutions from CO₂-reactive minerals (olivine endmembers), which are the rate-determining steps for CO₂ mineralization geosequestration. The leaching of Ca²⁺ from the Ca-olivine surface is a ligand exchange process that results in a much lower energy barrier with 10³ times faster dissolution rate compared to the leaching of Mg²⁺, which the tight magnesium sites on the forsterite (Mg-olivine) surface forbid ligand exchange. My results have implications in CO₂ mineralization geosequestration operations including the exploration of the desired mineralogy and the evaluation of enhanced mineralization mechanisms from first principle.