This was first attributed to the formation of carbonate anion radicals via the reaction OH Results obtained in the last decades point out that carbonates are key participants in a variety of oxidation processes. Usually the presence of CO2/HCO3-/CO32- is either forgotten or considered only as a buffer or proton transfer catalyst. Insights into K⁺ cations leaching and mineralization kinetics and their underlying mechanisms during the scCO2H2Oillite reaction is a matter of generalization in clay minerals for CO2 storage.ĬonspectusCO2, HCO3-, and CO32- are present in all aqueous media at pH > 4 if no major effort is made to remove them. This is a new report that demonstrates the mechanism of CO2 mineralization in clay minerals, presenting a potential solution for CO2 sequestration enhancement. These observations reveal that the clay-related mineralization is estimated to undergo an accumulated process, accessibly enhancing the amount of captured CO2. Magnesium carbonate nist webook free#Results of SEM-EDS, Raman and XPS measurements find that free CO2 clusters in contact with the leached interlayer cations can be converted into carbonate species through the mineralization reaction, precipitating at the surface and thus inducing interlayer swelling. In accordance with the experimental results, the K⁺ cations’ concentration in the filtrates progressively increases throughout the reaction. The leached K⁺ cations bond with the HCO3⁻ ions and later interact with the hydroxyl groups, forming K2CO3 molecules at the interface. Surface protonation leads to interlayer K⁺ cations hopping to the illite/fluids interface since the middle stage, mainly after 1 ns of the reaction. The MD simulation predicts the protonation of non-bridging oxygen (NBO) at the illite surface in the first picoseconds, resulting in HCO3⁻ ion formations via the bonding between CO2 molecules and hydroxyl group dissociated from H2O molecules. To clarify the storage mechanism, an alternative strategy for CO2 mineralization was investigated through molecular dynamics (MD) simulation and scCO2H2Oillite experiments. Understanding the reactive motion of mineral and fluids has dual advantages of resources and environment. The nucleation phenomenon of metal carbonates at ambient and supercritical conditions is explained from the perspective of cluster formation over time: Ca2+ ions can form prenucleation clusters at ambient temperature but show saturation with increasing temperature, whereas Na+ and Mg2+ ions show a rapid increase in cluster size and amount upon increasing time and temperature.Ĭlay minerals can be identified as a prospective target for long-term CO2 sequestration due to their accessible interlayer cations and periodic sheet structure. The formation and dissolution of bicarbonates and carbonates in solution were explored on the basis of the protonation capability in different systems. Residence time distribution analyses on different systems reveal the role of ions in accelerating and decelerating the dynamics of water and carbonate ions under different thermodynamic conditions. The angular distribution analysis explains the structural preference of carbonate ions to form carbonates and bicarbonates, where Na+ predominantly forms carbonates due to weaker angular strain, while Ca2+ and Mg2+ prefer to form bicarbonate monodentate in nature. The coordination radius and self-diffusion coefficient show good consistency with existing experimental and simulation results. The new metal carbonate force field has been validated using molecular dynamics simulations to study the solvation and reactivity of metal and carbonate ions in water at 300 K and 700 K. The Me-O-C (Me = metal) three-body valence angle parameters and Me-C non-reactive parameters of the force field have been optimized against quantum mechanical calculations including equations of state, heats of formation, heats of reaction, angle distortions and vibrational frequencies. This force field is fully transferable with previous ReaxFF water and water/electrolyte descriptions. A new ReaxFF reactive force field has been developed for metal carbonate systems including Na+, Ca2+, and Mg2+ cations and the CO32- anion.
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