Synthesis of multi-morphology anhydrous MgCO3 from brucite solid waste employing molecular effect on CO2 conversion via biodegradable chelating-system

Abstract

Brucite solid waste generated during mining is challenging to utilize directly and is often discarded, occupying a substantial space and causing environmental damages. This study proposed a novel single-step method for synthesizing anhydrous MgCO₃ via brucite solid waste carbonation with simultaneous carbon dioxide sequestration, aiming to mitigate environmental impact and enhance economic value. The Vitamin C was chosen as it is easily degraded to provide carbon source for mineralization. Results indicated multi-morphology anhydrous MgCO₃ was obtained, and the highest carbon dioxide sequestration rate was 46.7 %. Vitamin C bound Mg^2 + through -OH, inhibiting [Mg(H₂O)₆]²⁺ formation. Degradation-derived organic molecules adsorbed onto crystal surfaces, inducing the oriented growth and assembly of anhydrous MgCO₃. Density functional theory calculations revealed the formation of O-Mg bonds between Vitamin C and Mg²⁺. O-Mg bonds, intermolecular hydrogen bonds, and van der Waals forces exist between organic molecules and anhydrous MgCO₃. This method is anticipated to be an eco-friendly short-process technology for anhydrous MgCO₃ synthesis, with implications for environmental sustainability and carbon utilization strategies. Additionally, anhydrous MgCO₃ exhibits broad application potential in flame retardancy and electronic component enhancement, while the carbon spheres derived from Vitamin C degradation can be recycled for use as electrodes and adsorption materials.