Evolution of Natural Ferroan Brucite Under Different Atmospheres.

The study on the evolution of natural ferroan brucite (MgFe(OH) 2) was beneficial to discovering the function of brucite in the geologic cycle and directing the reasonable utilization of brucite resources. In this study, natural MgFe(OH)2 was characterized in detail and Rietveld refinement was employed to determine the precise content and existing environment of Fe 2 + . The reaction products of MgFe(OH)2 under various atmospheric conditions, including CO2, O2 and a mixed atmosphere of CO2 and O2 were innovatively investigated to gain insights into the evolution process and the crucial role played by Fe 2 + . Accordingly, the evolution mechanism of MgFe(OH)2 under different atmospheres was afforded based on the characterization and molecular simulations like electron transfer and binding energy. Fe 2 + in MgFe(OH)2 layers could be oxidized by O2 easily and give positive layers, CO 3 2 − produced by CO2 dissolving in water simultaneously was attracted to finally produce CO 3 2 − intercalated MgFe- layered double hydroxides (MgFe-CO 3 2 − -LDHs) which could be used as adsorbents, catalysts and so on. This process was supported by thermodynamics and also the dominant evolution route due to the dynamic reason. The existence of Fe 2 + in MgFe(OH)2 resulted in the diversity of the evolution products. This work highlighted the composition and structure of evolution products of natural MgFe(OH)2 under different environment as well as its possible application field. The evolution of MgFe(OH)2 under various atmospheric conditions was studied. The existence of Fe 2 + changed the evolution route of MgFe(OH)2 and made the reaction products diverse. Fe 2 + in MgFe(OH)2 layers could be oxidized by O2, and CO2 could be then adsorbed on the surface to finally produce MgFe-CO 3 2 − -LDHs thermodynamically. Due to dynamic reasons, the layers of MgFe(OH)2 would become positive because of the oxidation of Fe 2 + , CO 3 2 − in water was simultaneously attracted to produce MgFe-CO 3 2 − -LDHs. [ABSTRACT FROM AUTHOR]