Mineral carbonation using seawater as an alternative solvent represents a promising approach for carbon capture, utilization and storage (CCUS). Unlike conventional mineral carbonation that relies heavily on freshwater or chemical reagents, seawater provides an abundant and sustainable alternative solvent with inherent alkalinity and metal ions conducive to carbonation reactions; hence, mineral carbonation using seawater not only offers a viable solution to address freshwater scarcity concerns but also simultaneously reduces the cost and avoids the waste chemical generation. This study systematically investigated the effects of introduced CO₂ concentration (5–30%) and reaction temperature (10–30 °C) on carbonation performance in Ca and Mg systems using seawater. Results revealed distinct carbonation behaviors: the Ca system exhibited faster reaction kinetics with CO 2 predominantly captured as solid carbonates (CO 2 fixation capacity: 0.59 g-CO 2 /g-CaO), while the Mg system showed higher overall CO 2 uptake capacity (1.45 g-CO 2 /g-MgO) but lower CO 2 fixation capacity (0.03 g-CO 2 /g-MgO) due to greater retention in the aqueous phase. Lower introduced CO 2 concentrations and extended reaction times promoted solid carbonate formation, particularly in Mg systems. Temperature significantly influenced carbonate polymorphs in both Ca and Mg system. Orthogonal array analysis identified the relative significance of factors affecting CO 2 fixation capacity as: introduced CO 2 concentration > solid-liquid ratio > material type > temperature. The demonstrated effectiveness under low CO 2 concentrations suggests promising applicability for industrial flue gas without requiring costly purification and pressurization processes. These findings provide fundamental insights for optimizing seawater-based mineral carbonation as a sustainable CCUS technology.
Ho et al. (Sun,) studied this question.