Abstract
Dissolution of mineral in water is ubiquitous in nature and industry, especially for the calcium silicate species. However, the behavior of such a complex chemical reaction is still unclear at atomic level. Here, we show that the ab initio molecular dynamics and metadynamics simulations enable quantitative analyses of reaction pathways, and the thermodynamics and kinetics of calcium ion dissolution from the tricalcium silicate (Ca3SiO5) surface. The calcium sites with different coordination environment leads to different reaction pathways and free energy barriers. The low free energy barriers lead to that the detachment of calcium ions is a ligand exchange and auto-catalytic process. Moreover, the water adsorption, proton exchange and diffusion of water into the surface layer accelerate the leaching of calcium ions from the surface step by step. The discovery in this work thus would be a landmark for revealing the mechanism of cement hydration.
Origin of Free Energy Barriers of Decarboxylation and the Reverse Process of CO2 Capture in Dimethylformamide and in Water
