Molecular Dynamics Study between Amine Solution and Calcium Hydroxide

Abstract

Carbon dioxide can be captured by amines and carried into calcium hydroxide to generate calcium carbonate. In this study, molecular dynamics simulations were performed to study the interaction energy and structure between amine solution and calcium hydroxide crystal slab at the molecular level. MDEA was chosen as a representative amine. According to the one-dimensional concentration function, it was found that at a low ratio of MDEA, it was preferentially distributed close to the calcium hydroxide. And as the content in the solution increased, MDEA was gradually distributed equally throughout the aqueous solution. Compared to water, the interaction energy between MDEA and calcium hydroxide is greatly reduced and gradually decreases with increasing amine content. This means that the interaction between the two is reduced, and the reaction is more difficult to occur. In addition, the system of carbon dioxide dissolved in a solution of amine and water was simulated. The distribution of carbonate and bicarbonate was found to be relatively uniform at MDEA ratios of 5% and became irregular above 20%.

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