ScholarWorks@성균관대학교

초록

CO2 mineralization allows the transformation of magnesium hydroxide into magnesium carbonates under energy-efficient conditions. In this study, hydromagnesite (Mg5(CO3)4(OH)2.4H2O) was selectively synthesized via the carbonation of Mg(OH)2 in an aqueous sodium bicarbonate solution. Microwave heating provided rapid and uniform energy input to the reaction medium, thereby markedly suppressing the formation of metastable intermediates such as nesquehonite (MgCO3.3H2O) and dypingite (Mg5(CO3)4(OH)2.5H2O). When coupled with external CO2 feeding, the system maintained bicarbonate-rich and moderately alkaline conditions favored for Mg5(CO3)4(OH)2.4H2O crystallization while effectively inhibiting the formation of Na-Mg double carbonate phases. Structural, spectroscopic, and thermal analyses confirmed the complete carbonation of Mg(OH)2 and the formation of characteristic platelet-like Mg5(CO3)4(OH)2.4H2O. Furthermore, the post-carbonation solution demonstrated high reusability without the need for addition of sodium bicarbonate, underscoring its potential for continuous and scalable production of Mg5(CO3)4(OH)2.4H2O through repeated CO2 replenishment. Collectively, these results establish microwave-assisted carbonation as an efficient and practical route for producing phase-pure Mg5(CO3)4(OH)2.4H2O, offering concurrent benefits for CO2 mineralization and the manufacturing of high-value inorganic materials.

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