Evolution of Natural Ferroan Brucite Under Different Atmospheres
Abstract
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 Fe2+. 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 Fe2+. 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. Fe2+ in MgFe(OH)2 layers could be oxidized by O2 easily and give positive layers, CO2−3 produced by CO2 dissolving in water simultaneously was attracted to finally produce CO2−3 intercalated MgFe- layered double hydroxides (MgFe-CO2−3-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 Fe2+ 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.
