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Silicate Dissolution Mechanism from Metakaolinite Using Density Functional Theory

Metakaolin (MK) is a high-quality, reactive nanomaterial that holds promising potential for large-scale use in improving the sustainability of cement and concrete production. It can replace cement due to its pozzolanic reaction with calcium hydroxide and water to form cementitious compounds. Therefo...

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Autores principales: Izadifar, Mohammadreza, Ukrainczyk, Neven, Koenders, Eduardus
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10096740/
https://www.ncbi.nlm.nih.gov/pubmed/37049290
http://dx.doi.org/10.3390/nano13071196
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author Izadifar, Mohammadreza
Ukrainczyk, Neven
Koenders, Eduardus
author_facet Izadifar, Mohammadreza
Ukrainczyk, Neven
Koenders, Eduardus
author_sort Izadifar, Mohammadreza
collection PubMed
description Metakaolin (MK) is a high-quality, reactive nanomaterial that holds promising potential for large-scale use in improving the sustainability of cement and concrete production. It can replace cement due to its pozzolanic reaction with calcium hydroxide and water to form cementitious compounds. Therefore, understanding the dissolution mechanism is crucial to fully comprehending its pozzolanic reactivity. In this study, we present an approach for computing the activation energies required for the dissolution of metakaolin (MK) silicate units at far-from-equilibrium conditions using the improved dimer method (IDM) and the transition-state theory (TST) within density functional theory (DFT). Four different models were prepared to calculate the activation energies required for breaking oxo-bridging bonds between silicate or aluminate units. Our results showed that the activation energy for breaking the oxo-bridging bond to a silicate neighbor is higher than that to an aluminate neighbor due to the ionic interaction. However, for complete silicate tetrahedra dissolution, a higher activation energy is required for breaking the oxo-bridging bond to the aluminate neighbor compared to the silicate neighbor. The findings provide methodology for missing input data to predict the mesoscopic dissolution rate, e.g., by the atomistic kinetic Monte Carlo (KMC) upscaling approach.
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spelling pubmed-100967402023-04-13 Silicate Dissolution Mechanism from Metakaolinite Using Density Functional Theory Izadifar, Mohammadreza Ukrainczyk, Neven Koenders, Eduardus Nanomaterials (Basel) Article Metakaolin (MK) is a high-quality, reactive nanomaterial that holds promising potential for large-scale use in improving the sustainability of cement and concrete production. It can replace cement due to its pozzolanic reaction with calcium hydroxide and water to form cementitious compounds. Therefore, understanding the dissolution mechanism is crucial to fully comprehending its pozzolanic reactivity. In this study, we present an approach for computing the activation energies required for the dissolution of metakaolin (MK) silicate units at far-from-equilibrium conditions using the improved dimer method (IDM) and the transition-state theory (TST) within density functional theory (DFT). Four different models were prepared to calculate the activation energies required for breaking oxo-bridging bonds between silicate or aluminate units. Our results showed that the activation energy for breaking the oxo-bridging bond to a silicate neighbor is higher than that to an aluminate neighbor due to the ionic interaction. However, for complete silicate tetrahedra dissolution, a higher activation energy is required for breaking the oxo-bridging bond to the aluminate neighbor compared to the silicate neighbor. The findings provide methodology for missing input data to predict the mesoscopic dissolution rate, e.g., by the atomistic kinetic Monte Carlo (KMC) upscaling approach. MDPI 2023-03-27 /pmc/articles/PMC10096740/ /pubmed/37049290 http://dx.doi.org/10.3390/nano13071196 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Izadifar, Mohammadreza
Ukrainczyk, Neven
Koenders, Eduardus
Silicate Dissolution Mechanism from Metakaolinite Using Density Functional Theory
title Silicate Dissolution Mechanism from Metakaolinite Using Density Functional Theory
title_full Silicate Dissolution Mechanism from Metakaolinite Using Density Functional Theory
title_fullStr Silicate Dissolution Mechanism from Metakaolinite Using Density Functional Theory
title_full_unstemmed Silicate Dissolution Mechanism from Metakaolinite Using Density Functional Theory
title_short Silicate Dissolution Mechanism from Metakaolinite Using Density Functional Theory
title_sort silicate dissolution mechanism from metakaolinite using density functional theory
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10096740/
https://www.ncbi.nlm.nih.gov/pubmed/37049290
http://dx.doi.org/10.3390/nano13071196
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