A comparative study of the dissolution mechanisms of amorphous and crystalline feldspars at acidic pH conditions
Abstract The dissolution of amorphous and crystalline oligoclase, a Na-feldspar with traces of Ca and K, was investigated at 90 °C and acidic pH of 1.5 and 3 to unravel the impact of long- and short-range orders on silicate dissolution mechanisms. Experiments were conducted in solutions spiked with...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2022-04-01
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| Series: | npj Materials Degradation |
| Online Access: | https://doi.org/10.1038/s41529-022-00240-6 |
| _version_ | 1817988659011387392 |
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| author | Benjamin Cagnon Damien Daval Martiane Cabié Damien Lemarchand Stéphane Gin |
| author_facet | Benjamin Cagnon Damien Daval Martiane Cabié Damien Lemarchand Stéphane Gin |
| author_sort | Benjamin Cagnon |
| collection | DOAJ |
| description | Abstract The dissolution of amorphous and crystalline oligoclase, a Na-feldspar with traces of Ca and K, was investigated at 90 °C and acidic pH of 1.5 and 3 to unravel the impact of long- and short-range orders on silicate dissolution mechanisms. Experiments were conducted in solutions spiked with 29SiO2(aq) and saturated with respect to SiO2(am). Through morphology, structural, and composition characterizations, we showed that on the amorphous samples (glass samples), the altered layer was mostly formed by leaching, while a combination of both interfacial precipitation and leaching explains the layers formed on the crystalline sample. As expected, the altered layer was thicker at the most acidic pH and it became passivating on crystalline sample at pH 3. The alteration was faster on amorphous oligoclase than on its crystalline equivalent due to the more open structure of the glass. The preferential release of Al was suggested to play a key role, by weakening the silicate network of both substrates. Finally, in this study, a large overestimation of the global alteration of the materials was noticed based on the solution analyses. Discrepancies with solid analyses were attributed to an underestimation (≥2-fold factor) of the total reactive surface area. |
| first_indexed | 2024-04-14T00:37:45Z |
| format | Article |
| id | doaj.art-6dd1492c54194257a58b099e83a56779 |
| institution | Directory Open Access Journal |
| issn | 2397-2106 |
| language | English |
| last_indexed | 2024-04-14T00:37:45Z |
| publishDate | 2022-04-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj Materials Degradation |
| spelling | doaj.art-6dd1492c54194257a58b099e83a567792022-12-22T02:22:19ZengNature Portfolionpj Materials Degradation2397-21062022-04-016111310.1038/s41529-022-00240-6A comparative study of the dissolution mechanisms of amorphous and crystalline feldspars at acidic pH conditionsBenjamin Cagnon0Damien Daval1Martiane Cabié2Damien Lemarchand3Stéphane Gin4Université de Strasbourg/CNRS/ENGEES, ITESUniversité de Strasbourg/CNRS/ENGEES, ITESAix Marseille Univ, CNRS, Centrale Marseille, FSCM, CP2MUniversité de Strasbourg/CNRS/ENGEES, ITESCEA, DEN, DE2D, University of MontpellierAbstract The dissolution of amorphous and crystalline oligoclase, a Na-feldspar with traces of Ca and K, was investigated at 90 °C and acidic pH of 1.5 and 3 to unravel the impact of long- and short-range orders on silicate dissolution mechanisms. Experiments were conducted in solutions spiked with 29SiO2(aq) and saturated with respect to SiO2(am). Through morphology, structural, and composition characterizations, we showed that on the amorphous samples (glass samples), the altered layer was mostly formed by leaching, while a combination of both interfacial precipitation and leaching explains the layers formed on the crystalline sample. As expected, the altered layer was thicker at the most acidic pH and it became passivating on crystalline sample at pH 3. The alteration was faster on amorphous oligoclase than on its crystalline equivalent due to the more open structure of the glass. The preferential release of Al was suggested to play a key role, by weakening the silicate network of both substrates. Finally, in this study, a large overestimation of the global alteration of the materials was noticed based on the solution analyses. Discrepancies with solid analyses were attributed to an underestimation (≥2-fold factor) of the total reactive surface area.https://doi.org/10.1038/s41529-022-00240-6 |
| spellingShingle | Benjamin Cagnon Damien Daval Martiane Cabié Damien Lemarchand Stéphane Gin A comparative study of the dissolution mechanisms of amorphous and crystalline feldspars at acidic pH conditions npj Materials Degradation |
| title | A comparative study of the dissolution mechanisms of amorphous and crystalline feldspars at acidic pH conditions |
| title_full | A comparative study of the dissolution mechanisms of amorphous and crystalline feldspars at acidic pH conditions |
| title_fullStr | A comparative study of the dissolution mechanisms of amorphous and crystalline feldspars at acidic pH conditions |
| title_full_unstemmed | A comparative study of the dissolution mechanisms of amorphous and crystalline feldspars at acidic pH conditions |
| title_short | A comparative study of the dissolution mechanisms of amorphous and crystalline feldspars at acidic pH conditions |
| title_sort | comparative study of the dissolution mechanisms of amorphous and crystalline feldspars at acidic ph conditions |
| url | https://doi.org/10.1038/s41529-022-00240-6 |
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