CO2 Absorption and Magnesium Carbonate Precipitation in MgCl2–NH3–NH4Cl Solutions: Implications for Carbon Capture and Storage

Abstract

CO 2 absorption and carbonate precipitation are the two core processes controlling the reaction rate and path of CO 2 mineral sequestration. Whereas previous studies have focused on testing reactive crystallization and precipitation kinetics, much less attention has been paid to absorption, the key process determining the removal efficiency of CO 2 . In this study, adopting a novel wetted wall column reactor, we systematically explore the rates and mechanisms of carbon transformation from CO 2 gas to carbonates in MgCl 2 -NH 3 -NH 4 Cl solutions. We find that reactive diffusion in liquid film of the wetted wall column is the rate-limiting step of CO 2 absorption when proceeding chiefly through interactions between CO 2 (aq) and NH 3 (aq). We further quantified the reaction kinetic constant of the CO 2 -NH 3 reaction. Our results indicate that higher initial concentration of NH 4 Cl (≥ 2 mol·L −1 ) leads to the precipitation of roguinite, while nesquehonite appears to be the dominant Mg-carbonate without NH 4 Cl addition. We also noticed dypingite formation via phase transformation in hot water. This study provides new insight into the reaction kinetics of CO 2 mineral carbonation that indicates the potential of this technique for future application to industrial-scale CO 2 sequestration.

Advancements, Challenges, and Perspectives of Flue Gas Injection in Subsurface Formations: A Comprehensive Review

“…This is particularly important in the context of CCS, where flue gases from power plants are injected into geological formations for long-term storage. 107 Flue gases, which are produced during the combustion of fossil fuels, contain various components like CO 2 , NO X , SO X , and trace gases. When injected into the reservoir during EOR operations, these gases can interact with the minerals present in the formation, leading to dissolution and precipitation reactions.…”

“…The software also enables the modeling of the effects of other components present in flue gases, such as nitrogen oxides (NO X ) and sulfur oxides (SO X ), on the kinetics of geochemical reactions. This is particularly important in the context of CCS, where flue gases from power plants are injected into geological formations for long-term storage . Flue gases, which are produced during the combustion of fossil fuels, contain various components like CO 2 , NO X , SO X , and trace gases.…”

Advances in process development of aqueous CO2 mineralisation towards scalability

“…This could be explained by the length of alkyl chain and the van der Waals force between the precipitates and the additive and also the polar interaction from the hydrophilic groups which can transform the polymorphs. Zhu et al (2017) studied the MgCl2-NH3-NH4Cl system for CO2 mineralisation with a wetted wall column reactor. It was found that the diffusion of the reactants in the liquid film was the rate-limiting step based on the kinetics study.…”

Influence of Cations on Direct CO2 Capture and Mineral Film Formation: The Role of KCl and MgCl2 at the Air/Electrolyte/Iron Interface

“…On solid interfaces, metal oxide surfaces have been shown to have a high absorption capacity for CO 2 . Magnesium oxide (MgO) and calcium oxide (CaO), present in various water sources, are the preferred materials for CO 2 capture due to the high absorption rates of Mg 2+ and Ca 2+ . − Other studies have shown that metal hydroxides (Fe­(OH) 2 , Co­(OH) 2 , and Ni­(OH) 2 ) are efficient adsorbents for capturing CO 2 , producing metal carbonate (MCO 3 ) and H 2 O as products . Correlations have been found between CO 2 uptake and humidity, where water dissociation provides basic OH sites for reaction with the acidic CO 2 . ,, Studies have shown that oxide supports modified with other alkali metals have a high capacity for CO 2 adsorption .…”