Development of a kinetic-thermodynamic model for lime-stabilization of Na-bentonite
Abstract This study presents the first kinetic model to predict the solid and pore solution composition of Na-bentonite clay reacting with slaked lime over a period of 720 days. The model successfully accounts for most experimental data using a single kinetic rate constant. The following sequence of...
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BMC
2025-07-01
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| Series: | Geochemical Transactions |
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| Online Access: | https://doi.org/10.1186/s12932-025-00103-4 |
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| author | Tasneem Ahmadullah Maria Chrysochoou |
| author_facet | Tasneem Ahmadullah Maria Chrysochoou |
| author_sort | Tasneem Ahmadullah |
| collection | DOAJ |
| description | Abstract This study presents the first kinetic model to predict the solid and pore solution composition of Na-bentonite clay reacting with slaked lime over a period of 720 days. The model successfully accounts for most experimental data using a single kinetic rate constant. The following sequence of reactions was predicted by the model: initial rapid dissolution of portlandite within the first 7 days, leading to a decrease in pH and dissolved calcium, and concurrent formation of calcium silicate hydrates (C-S-H: jennite), calcium aluminate hydrate (C-A-H: C₄AH₁₃), calcium aluminosilicate hydrates (stratlingite) and hydrotalcite. After 7 days, jennite and stratlingite are predicted to transform into tobermorite-II, contributing to strength development up to 28 days. From 28 to 90 days, continued montmorillonite dissolution is predicted, along with minor formation of ettringite, partial tobermorite-II dissolution, and precipitation of secondary phases such as albite and talc. Experimentally, portlandite dissolution was confirmed by TGA and XRD and found to be complete within 7 days, in agreement with model predictions. However, other predicted solid-phase transformations (e.g., tobermorite-II formation and dissolution, ettringite, albite, and talc formation) could not be conclusively verified through experimental techniques. Aqueous phase measurements confirmed that the pH and Ca trends in solution, and that equilibrium was reached by 90 days. |
| format | Article |
| id | doaj-art-3efb05b21bc241f0850d2e17c1a63117 |
| institution | Kabale University |
| issn | 1467-4866 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | BMC |
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| series | Geochemical Transactions |
| spelling | doaj-art-3efb05b21bc241f0850d2e17c1a631172025-08-20T04:03:07ZengBMCGeochemical Transactions1467-48662025-07-0126111310.1186/s12932-025-00103-4Development of a kinetic-thermodynamic model for lime-stabilization of Na-bentoniteTasneem Ahmadullah0Maria Chrysochoou1Pacific Northwest National LaboratoryCollege of Engineering, University of MissouriAbstract This study presents the first kinetic model to predict the solid and pore solution composition of Na-bentonite clay reacting with slaked lime over a period of 720 days. The model successfully accounts for most experimental data using a single kinetic rate constant. The following sequence of reactions was predicted by the model: initial rapid dissolution of portlandite within the first 7 days, leading to a decrease in pH and dissolved calcium, and concurrent formation of calcium silicate hydrates (C-S-H: jennite), calcium aluminate hydrate (C-A-H: C₄AH₁₃), calcium aluminosilicate hydrates (stratlingite) and hydrotalcite. After 7 days, jennite and stratlingite are predicted to transform into tobermorite-II, contributing to strength development up to 28 days. From 28 to 90 days, continued montmorillonite dissolution is predicted, along with minor formation of ettringite, partial tobermorite-II dissolution, and precipitation of secondary phases such as albite and talc. Experimentally, portlandite dissolution was confirmed by TGA and XRD and found to be complete within 7 days, in agreement with model predictions. However, other predicted solid-phase transformations (e.g., tobermorite-II formation and dissolution, ettringite, albite, and talc formation) could not be conclusively verified through experimental techniques. Aqueous phase measurements confirmed that the pH and Ca trends in solution, and that equilibrium was reached by 90 days.https://doi.org/10.1186/s12932-025-00103-4Lime stabilizationGeochemical modelingChemical kineticsNa-bentonitePozzolanic reaction |
| spellingShingle | Tasneem Ahmadullah Maria Chrysochoou Development of a kinetic-thermodynamic model for lime-stabilization of Na-bentonite Geochemical Transactions Lime stabilization Geochemical modeling Chemical kinetics Na-bentonite Pozzolanic reaction |
| title | Development of a kinetic-thermodynamic model for lime-stabilization of Na-bentonite |
| title_full | Development of a kinetic-thermodynamic model for lime-stabilization of Na-bentonite |
| title_fullStr | Development of a kinetic-thermodynamic model for lime-stabilization of Na-bentonite |
| title_full_unstemmed | Development of a kinetic-thermodynamic model for lime-stabilization of Na-bentonite |
| title_short | Development of a kinetic-thermodynamic model for lime-stabilization of Na-bentonite |
| title_sort | development of a kinetic thermodynamic model for lime stabilization of na bentonite |
| topic | Lime stabilization Geochemical modeling Chemical kinetics Na-bentonite Pozzolanic reaction |
| url | https://doi.org/10.1186/s12932-025-00103-4 |
| work_keys_str_mv | AT tasneemahmadullah developmentofakineticthermodynamicmodelforlimestabilizationofnabentonite AT mariachrysochoou developmentofakineticthermodynamicmodelforlimestabilizationofnabentonite |