The role of background electrolytes on the kinetics and mechanism of calcite dissolution
The influence of background electrolytes on the mechanism and kinetics of calcite dissolution was investigated using in situ Atomic Force Microscopy (AFM). Experiments were carried out far from equilibrium by passing alkali halide salt (NaCl, NaF, NaI, KCl and LiCl) solutions over calcite cleavage s...
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| Format: | Journal Article |
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Pergamon
2010
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| Online Access: | http://hdl.handle.net/20.500.11937/38014 |
| _version_ | 1848755204897374208 |
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| author | Ruiz-Agudo, E. Kowacz, M. Putnis, Christine Putnis, Andrew |
| author_facet | Ruiz-Agudo, E. Kowacz, M. Putnis, Christine Putnis, Andrew |
| author_sort | Ruiz-Agudo, E. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The influence of background electrolytes on the mechanism and kinetics of calcite dissolution was investigated using in situ Atomic Force Microscopy (AFM). Experiments were carried out far from equilibrium by passing alkali halide salt (NaCl, NaF, NaI, KCl and LiCl) solutions over calcite cleavage surfaces. This AFM study shows that all the electrolytes tested enhance the calcite dissolution rate. The effect and its magnitude is determined by the nature and concentration of the electrolyte solution. Changes in morphology of dissolution etch pits and dissolution rates are interpreted in terms of modification in water structure dynamics (i.e. in the activation energy barrier of breaking water-water interactions), as well as solute and surface hydration induced by the presence of different ions in solution. At low ionic strength, stabilization of water hydration shells of calcium ions by non-paired electrolytes leads to a reduction in the calcite dissolution rate compared to pure water. At high ionic strength, salts with a common anion yield similar dissolution rates, increasing in the order Cl- < I- < F- for salts with a common cation due to an increasing mobility of water around the calcium ion. Changes in etch pit morphology observed in the presence of F- and Li+ are explained by stabilization of etch pit edges bonded by like-charged ions and ion incorporation, respectively. As previously reported and confirmed here for the case of F-, highly hydrated ions increased the etch pit nucleation density on calcite surfaces compared to pure water. This may be related to a reduction in the energy barrier for etch pit nucleation due to disruption of the surface hydration layer. © 2009 Elsevier Ltd. All rights reserved. |
| first_indexed | 2025-11-14T08:52:36Z |
| format | Journal Article |
| id | curtin-20.500.11937-38014 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:52:36Z |
| publishDate | 2010 |
| publisher | Pergamon |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-380142017-09-13T14:13:45Z The role of background electrolytes on the kinetics and mechanism of calcite dissolution Ruiz-Agudo, E. Kowacz, M. Putnis, Christine Putnis, Andrew The influence of background electrolytes on the mechanism and kinetics of calcite dissolution was investigated using in situ Atomic Force Microscopy (AFM). Experiments were carried out far from equilibrium by passing alkali halide salt (NaCl, NaF, NaI, KCl and LiCl) solutions over calcite cleavage surfaces. This AFM study shows that all the electrolytes tested enhance the calcite dissolution rate. The effect and its magnitude is determined by the nature and concentration of the electrolyte solution. Changes in morphology of dissolution etch pits and dissolution rates are interpreted in terms of modification in water structure dynamics (i.e. in the activation energy barrier of breaking water-water interactions), as well as solute and surface hydration induced by the presence of different ions in solution. At low ionic strength, stabilization of water hydration shells of calcium ions by non-paired electrolytes leads to a reduction in the calcite dissolution rate compared to pure water. At high ionic strength, salts with a common anion yield similar dissolution rates, increasing in the order Cl- < I- < F- for salts with a common cation due to an increasing mobility of water around the calcium ion. Changes in etch pit morphology observed in the presence of F- and Li+ are explained by stabilization of etch pit edges bonded by like-charged ions and ion incorporation, respectively. As previously reported and confirmed here for the case of F-, highly hydrated ions increased the etch pit nucleation density on calcite surfaces compared to pure water. This may be related to a reduction in the energy barrier for etch pit nucleation due to disruption of the surface hydration layer. © 2009 Elsevier Ltd. All rights reserved. 2010 Journal Article http://hdl.handle.net/20.500.11937/38014 10.1016/j.gca.2009.11.004 Pergamon restricted |
| spellingShingle | Ruiz-Agudo, E. Kowacz, M. Putnis, Christine Putnis, Andrew The role of background electrolytes on the kinetics and mechanism of calcite dissolution |
| title | The role of background electrolytes on the kinetics and mechanism of calcite dissolution |
| title_full | The role of background electrolytes on the kinetics and mechanism of calcite dissolution |
| title_fullStr | The role of background electrolytes on the kinetics and mechanism of calcite dissolution |
| title_full_unstemmed | The role of background electrolytes on the kinetics and mechanism of calcite dissolution |
| title_short | The role of background electrolytes on the kinetics and mechanism of calcite dissolution |
| title_sort | role of background electrolytes on the kinetics and mechanism of calcite dissolution |
| url | http://hdl.handle.net/20.500.11937/38014 |