Transformation of amorphous calcium carbonate in the presence of magnesium, phosphate, and mineral surfaces

Molnár, Zsombor; Dódony, István; Pósfai, Mihály

doi:10.1016/j.gca.2023.01.028

Cited by 15 publications

(3 citation statements)

References 54 publications

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“…2A; Fig. S2 and S3†) with d -values corresponding to those reported by Molnár et al 41 Mg-ACC particles contained a significant amount of Mg (Fig. 2B–C and Fig.…”

Section: Resultssupporting

confidence: 84%

Formation and properties of spindle-shaped aragonite mesocrystals from Mg-bearing solutions

Molnár,

Pekker,

Rečnik

et al. 2024

Nanoscale

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“…2A; Fig. S2 and S3†) with d -values corresponding to those reported by Molnár et al 41 Mg-ACC particles contained a significant amount of Mg (Fig. 2B–C and Fig.…”

Section: Resultssupporting

confidence: 84%

Formation and properties of spindle-shaped aragonite mesocrystals from Mg-bearing solutions

Molnár,

Pekker,

Rečnik

et al. 2024

Nanoscale

Self Cite

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“…The major minerals precipitated in the experiments were a smectite clay and a mixed Mg, Fe, Ca carbonate. The formation of these clays may enhance carbonate mineral precipitation (Molnar et al, 2021(Molnar et al, , 2023. The eventual formation of zeolite minerals was also suggested by the reactive fluid compositions during the experiments.…”

Section: Pre-injection Experimental Studiesmentioning

confidence: 73%

Carbon Capture and Storage: From Global Cycles to Global Solutions

Oelkers,

Gislason

2023

Geochem. Persp.

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Anthropogenic carbon emissions have overwhelmed the natural carbon cycle, leading to a dramatic increase in atmospheric CO2 concentration. The rate of this increase may be unprecedented in Earth’s history and is leading to a substantial increase in global temperatures, ocean acidification, sea level rise and potentially human health challenges. In this Geochemical Perspectives we review the natural carbon cycle and its link to global climate. Notably, as directly observed by field observations summarised in this volume, there is a natural negative feedback loop between increasing global temperature, continental weathering rates, and CO2 that has tended to limit Earth climate changes over geological time scales. Due to the rapid increase in atmospheric carbon concentrations, global average temperatures have increased by more than 1.2 °C since the start of the industrial revolution. One way to slow or even arrest this increasing global average temperature is through Carbon Capture and Storage (CCS). Carbon dioxide can be captured either from large industrial point sources or directly from the atmosphere. Taking account of the natural carbon cycle, the most secure approach to storing captured CO2 is by reacting it with mafic or ultramafic rocks to form stable carbonate minerals, a process referred to as “mineral carbonation”. Although mineral carbonation can occur and be accelerated at the Earth’s surface, due to the required scale and required time frames it is most effective in the subsurface. This subsurface mineralisation approach was developed into an industrial scale process through an academic-industrial collaboration called CarbFix. The history of CarbFix, from its beginnings as a concept through its installation as an industrial process is presented in detail. This Geochemical Perspectives concludes with an assessment of the future of subsurface mineralisation as a means to help address the global warming challenge, as well as a detailed list of potential research directions that need to be addressed to further upscale and optimise this carbon storage approach.

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“…This is in line with the buffering effect of HCO 3 − anions, which are converted to CO 3 2− at high pH (see eq 2) and with the incorporation of carbonate anions into the growing calcium carbonate precipitates, which also results in a pH decrease. 56,57 There was also no large increase in pH-sensitive fluorescence intensity in experiments performed under confinement (Figure S6B,C). These data show preferential dye incorporation into growing crystals associated with a strong local increase in the fluorescence intensity in regions with crystals and a drop in the fluorescence intensity of the confined solution (Figure S6D).…”

Section: ■ Materials and Methodsmentioning

confidence: 90%

Electrochemically Assisted Growth of Hopper and Tabular Calcite under Confinement

Dziadkowiec,

Linga,

Kalchgruber

et al. 2024

Crystal Growth & Design

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Crystallization under confinement is commonplace in nature and offers new pathways to engineer crystals with the desired morphologies in a controlled and reproducible manner. In this work, we demonstrate the electrochemically assisted, in situ formation of hopper and tabular calcite crystals within a wedge-like pore formed by confinement induced by the surface force apparatus (SFA). In this geometry, the distance between the confining surfaces decreases continuously from hundreds of micrometers to a few nanometers in a single experimental setup. Calcium carbonate precipitation followed in real-time is triggered by elevating the pH and thus supersaturation directly inside the pore. The pH increase is tracked with a fluorophore tracer and calculated analytically. The unusual calcite crystal habits are obtained in the absence of precipitation-modifying additives and vary as a function of the distance between the confining walls, where at the largest surface separations, hopper crystals form on the gold surface, whereas flat, tabular calcite forms on mica when the confining distance was below 5 μm. Hexagonal or triangular calcite plates exhibit surfaces dominantly defined by rough (001) planes and increase in their surface area-to-volume ratios with decreasing SFA pore thickness. Stabilization of calcite plates bound by (001) faces is a cooperative effect of the oriented growth of calcite on the confining, negatively charged mica walls and the confinement shape, which promotes the development of calcite morphology in the rapid crystal growth directions. The heterogeneous crystallization of calcite is preceded by the nucleation and spreading of a front composed of submicrometer-sized calcium carbonate particles visualized in situ in the SFA pore. Our work demonstrates abundant crystal growth under nanoscale confinement facilitated by elevated pH and a high surface charge of the confining walls.

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Transformation of amorphous calcium carbonate in the presence of magnesium, phosphate, and mineral surfaces

Cited by 15 publications

References 54 publications

Formation and properties of spindle-shaped aragonite mesocrystals from Mg-bearing solutions

Formation and properties of spindle-shaped aragonite mesocrystals from Mg-bearing solutions

Carbon Capture and Storage: From Global Cycles to Global Solutions

Electrochemically Assisted Growth of Hopper and Tabular Calcite under Confinement

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