Temporal evolution of dissolution kinetics of polycrystalline calcite

Bollermann, Till

doi:10.2475/01.2020.04

Cited by 20 publications

(24 citation statements)

References 60 publications

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“…Parametrization of the new model is according to literature data and utilizes several sitespecific rate contributors. These rate contributors are determined by statistical analysis of dissolution rate maps in VSI and -CT experiments (Bollermann and Fischer 2020). More specifically, local dissolution rates are measured at the micrometer-scale and the site-specific rate contributors are identified by clustering, where the rate contributors form centers of rate-clusters.…”

Section: Rate Componentsmentioning

confidence: 99%

“…Thus, the available rate components cover in part the pH-depending calcite dissolution rate function. Highest rates at crystal corners [Table 2 (1)] are based on surface data by Bollermann and Fischer (2020) and powder data measured by Rickard and Sjoeberg (1983). The specific material preparation of powder for dissolution experiments results in a high kink site density of such material; thus, the rate range is similar to that of the crystal corners.…”

Section: Rate Componentsmentioning

confidence: 99%

“…However, such combined data, i.e., averaged data of the complex multimodal rate spectrum, provide no site-specific information. Thus, Table 2 (2) provides crystal edge data based on a single dataset only (Bollermann and Fischer 2020). Crystal facets were analyzed using multiple microscopic methods for direct rate measurements, e.g., in Brand et al (2017).…”

Section: Rate Componentsmentioning

confidence: 99%

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Implementing the Variability of Crystal Surface Reactivity in Reactive Transport Modeling

2021

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Current reactive transport model (RTM) uses transport control as the sole arbiter of differences in reactivity. For the simulation of crystal dissolution, a constant reaction rate is assumed for the entire crystal surface as a function of chemical parameters. However, multiple dissolution experiments confirmed the existence of an intrinsic variability of reaction rates, spanning two to three orders of magnitude. Modeling this variance in the dissolution process is vital for predicting the dissolution of minerals in multiple systems. Novel approaches to solve this problem are currently under discussion. Critical applications include reactions in reservoir rocks, corrosion of materials, or contaminated soils. The goal of this study is to provide an algorithm for multi-rate dissolution of single crystals, to discuss its software implementation, and to present case studies illustrating the difference between the single rate and multi-rate dissolution models. This improved model approach is applied to a set of test cases in order to illustrate the difference between the new model and the standard approach. First, a Kossel crystal is utilized to illustrate the existence of critical rate modes of crystal faces, edges, and corners. A second system exemplifies the effect of multiple rate modes in a reservoir rock system during calcite cement dissolution in a sandstone. The results suggest that reported variations in average dissolution rates can be explained by the multi-rate model, depending on the geometric configurations of the crystal surfaces.

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Section: Rate Componentsmentioning

confidence: 99%

Section: Rate Componentsmentioning

confidence: 99%

Section: Rate Componentsmentioning

confidence: 99%

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Implementing the Variability of Crystal Surface Reactivity in Reactive Transport Modeling

2021

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“…The application of surface-sensitive methods, such as atomic force microscopy (AFM), − vertical scanning interferometry (VSI), − and transmission X-ray microscopy (TXM) − confirmed the intrinsic variability of crystal surface reactivity. Crystal corners and edges as well as nanorough surfaces showing etch pits, surface steps, and so forth show a higher reactivity than the flat areas. ,, This led to the interpretation that regions near the edges and corners with higher surface curvature tend to support higher dissolution rates. Specifically, the locally enhanced density of surface steps and kink sites of such surface portions does mechanistically control the observed differences in reactivity …”

Section: Introductionmentioning

confidence: 99%

“…Crystal corners and edges as well as nanorough surfaces showing etch pits, surface steps, and so forth show a higher reactivity than the flat areas. ,, This led to the interpretation that regions near the edges and corners with higher surface curvature tend to support higher dissolution rates. Specifically, the locally enhanced density of surface steps and kink sites of such surface portions does mechanistically control the observed differences in reactivity …”

Section: Introductionmentioning

confidence: 99%

Implementing Heterogeneous Crystal Surface Reactivity in Reactive Transport Simulations: The Example of Calcite Dissolution

Karimzadeh

2021

ACS Earth Space Chem.

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Both surface reactivity and fluid dynamics control the dissolution kinetics of crystalline material. In this study, we performed a 3D reactive transport simulation to investigate the impact of surface topography heterogeneity superimposed to fluid transport heterogeneity on the dissolution rate of calcite. The model simulates the chemical reaction of calcite dissolution, solute transport, and crystal surface geometry evolution. Importantly, we introduce heterogeneous surface reactivity into the reactive transport simulation. We test the surface slope factor as a proxy value for the intrinsic surface reactivity of dissolving crystal surface nanotopographies. Experimental data sets collected using vertical scanning interferometry validate this approach. The novel parametrization allows for the simulation of surface-controlled heterogeneous reactivity in reactive transport simulations of mineral surface dissolution.

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Variability of Radionuclide Sorption Efficiency on Muscovite Cleavage Planes

Schabernack,

Oliveira,

Heine

et al. 2023

Advcd Theory and Sims

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In deep geological repositories for nuclear waste, the surrounding rock formation serves as an important barrier against radionuclide migration. Multiple potential host rocks contain phyllosilicates, which have shown high efficiency in radionuclide sorption. Recent experimental studies report a heterogeneous distribution of adsorbed radionuclides on nanotopographic mineral surfaces. In this study, the energetic differences of surface sorption sites available at nanotopographic structures such as steps, pits, and terraces are investigated. Eleven important surface sites are selected and the energies of ad‐ and desorption reactions are obtained from density functional theory calculations. The adsorption energies are then used for the parameterization of a kinetic Monte Carlo model simulating the distribution of adsorbed europium on a typical nanotopographic muscovite surface. On muscovite, silicon step sites are favorable for europium sorption and lead to an increased adsorption in regions with high step concentrations. Under identical chemical conditions, sorption on typical nanotopographic surfaces is increased by a factor of three compared to atomically flat surfaces. Desorption occurs preferentially at terrace sites, leading to an overall 2.5 times increased retention at nanotopographic structures. This study provides a mechanistic explanation for heterogeneous sorption on nanotopographic mineral surfaces due to the availability of energetically favorable sorption sites.

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Temporal evolution of dissolution kinetics of polycrystalline calcite

Cited by 20 publications

References 60 publications

Implementing the Variability of Crystal Surface Reactivity in Reactive Transport Modeling

Implementing the Variability of Crystal Surface Reactivity in Reactive Transport Modeling

Implementing Heterogeneous Crystal Surface Reactivity in Reactive Transport Simulations: The Example of Calcite Dissolution

Variability of Radionuclide Sorption Efficiency on Muscovite Cleavage Planes

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