Hydrodynamic factors influencing mineral dissolution rates

Pan, Feng; Ye, Shaoxiong; Martys, Nicos; Bullard, Jeffrey W.

doi:10.1016/j.chemgeo.2020.119578

Cited by 10 publications

(12 citation statements)

References 48 publications

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“…However, further calculations showed that the saturation was nonzero in this case. Similar calculations predicted that a flow rate of 35 mL/min of deionized water in the same cell gives an approximately zero saturation at the leading edge of the calcite crystal, i.e., at the points of the crystal closest to the inlet. In these conditions, Feng et al obtained the following rates at the leading edges of three studied samples, in μmol/(m 2 s): 0.2–0.3 (sample 3); ≈0.6 (sample 4); 0.3–0.4 (sample 5); see Figure 2 of that work.…”

Section: Discussionmentioning

confidence: 60%

“…Recent studies used DHM to obtain the calcite dissolution rate from surface retreats and obtained results that are representative of the conditions considered in our simulations. , …”

Section: Discussionmentioning

confidence: 93%

“…We consider dissolution under far-from-equilibrium conditions, i.e., with negligible precipitation. This is achieved with sufficiently fast convective transport near the crystal surface; see, e.g., recent experiments and hydrodynamic simulations by Feng et al that show how to reach that condition. The dissolution is modeled by irreversible detachment of sites from the crystal surface.…”

Section: Model and Methodsmentioning

confidence: 91%

“…The surface images obtained by Feng et al . have 650 pixels in each direction and resolution of 340 nm, so the lateral scan size is 221 μm.…”

Section: Discussionmentioning

confidence: 99%

“…The advances in microscopy techniques permit the study of calcite dissolution kinetics with high resolution and good accuracy, , which is a motivation to improve the existing models. From AFM images, the velocities of step propagation in different directions and the rates of pit nucleation and growth (at defects or in defect-free regions) were obtained under several conditions. ,− Improvement of AFM techniques allows the investigation of processes at a molecular scale. ,− Using vertical scanning interferometry (VSI), it is possible to obtain dissolution rate spectra of calcite surfaces, which reveal the effects of the local morphology on the local rates. − Digital holographic microscopy (DHM) is another useful technique to determine velocities of surface retreat. − …”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Simulations of Dissolution of Initially Flat Calcite Surfaces: Retreat Velocity Control and Surface Roughness Scaling

Carrasco

Machado

Reis

2021

ACS Earth Space Chem.

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The far-from-equilibrium alkaline dissolution of initially flat and defect-free calcite surfaces is modeled with kinetic Monte Carlo simulations of site detachment from a Kossel crystal and with scaling approaches. The surface retreat velocity is strongly dependent on the detachment rate of the highest coordination sites, which represent molecules in the middle of (101̅4) terraces. The comparison with a recent velocity estimate from digital holographic microscopy predicts the removal rate of those molecules between 2 × 10–7 and 4 × 10–6 s–1 at room temperature, which improves a previous estimate from a grain dissolution model. The activation energy for this molecular-scale process is estimated as 92 ± 6 kJ/mol (assuming the same prefactor ∼3 × 1010 s–1 of kink and step sites). The areal density of nonterrace sites (mostly steps and kinks) is also related to that removal rate, so we propose that the measurement of this density may provide independent estimates of the above quantities. Arrhenius plots of the retreat velocities obtained in high-temperature simulations predict the (macroscopic) activation energy of 69 ± 4 kJ/mol for dissolution of smooth surfaces. We also show that the scaling of the surface roughness in time and size is the same as in the Kardar–Parisi–Zhang (KPZ) equation of kinetic roughening. However, room-temperature roughening of initially smooth calcite surfaces is so slow that it is unlikely to be observed in typical experimental times and the alkaline conditions modeled here. Since the rates in acidic media are larger and arguing that the microscopic symmetries of the molecule detachment processes should be preserved, we suggest the investigation of KPZ scaling under those conditions.

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Section: Discussionmentioning

confidence: 60%

“…Recent studies used DHM to obtain the calcite dissolution rate from surface retreats and obtained results that are representative of the conditions considered in our simulations. , …”

Section: Discussionmentioning

confidence: 93%

Section: Model and Methodsmentioning

confidence: 91%

“…The surface images obtained by Feng et al . have 650 pixels in each direction and resolution of 340 nm, so the lateral scan size is 221 μm.…”

Section: Discussionmentioning

confidence: 99%