Mulders, JJPA;
Tobler, DJ;
Oelkers, EH;
(2021)
Siderite nucleation pathways as a function of aqueous solution saturation state at 25 °C.
Chemical Geology
, 559
, Article 119947. 10.1016/j.chemgeo.2020.119947.
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Abstract
The mechanisms of siderite (FeCO3) nucleation from aqueous solution depend on the fluid saturation state. In this study we investigate the effect of aqueous fluid saturation on the nucleation pathway of siderite. Thereof, we performed a series of turbidity and batch experiments. Turbidity measurements indicate that at low saturation indices (SI < 3.69), siderite nucleation proceeds via the direct nucleation of crystalline siderite from the aqueous fluid. The direct precipitation of crystalline siderite is confirmed by X-Ray diffraction (XRD) analysis. This is the first study to report the direct nucleation of siderite at near-equilibrium conditions. At higher saturation indices (SI ≥ 3.69), nucleation proceeds via the initial precipitation of amorphous ferrous carbonate (AFC) followed by the nucleation and growth of crystalline siderite. XRD spectra confirm the initial precipitation of AFC and its transformation to crystalline siderite. Such differences in the nucleation mechanism likely affect both the reactivity of the resulting siderite and its isotopic composition. Insight into the aqueous fluid saturation state during siderite nucleation could thus be crucial for the accurate interpretation of the isotopic signature in natural systems.
| Type: | Article |
|---|---|
| Title: | Siderite nucleation pathways as a function of aqueous solution saturation state at 25 °C |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.chemgeo.2020.119947 |
| Publisher version: | https://doi.org/10.1016/j.chemgeo.2020.119947 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Siderite, Nucleation mechanisms, Saturation state, Amorphous ferrous carbonate |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10131249 |
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