A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site Geometry
Barite (Ba[SO<sub>4</sub>]) is one of the promising candidates for sequestration of radioactive waste. Barite can incorporate radium (Ra) and form ideal solid solutions, i.e., (Ba,Ra)[SO<sub>4</sub>]. Together with isostructural celestite (Sr[SO<sub>4</sub>]), ter...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-05-01
|
| Series: | Minerals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-163X/12/5/639 |
| _version_ | 1797497555584548864 |
|---|---|
| author | Inna Kurganskaya Nikolay Trofimov Andreas Luttge |
| author_facet | Inna Kurganskaya Nikolay Trofimov Andreas Luttge |
| author_sort | Inna Kurganskaya |
| collection | DOAJ |
| description | Barite (Ba[SO<sub>4</sub>]) is one of the promising candidates for sequestration of radioactive waste. Barite can incorporate radium (Ra) and form ideal solid solutions, i.e., (Ba,Ra)[SO<sub>4</sub>]. Together with isostructural celestite (Sr[SO<sub>4</sub>]), ternary solid solutions, (Ba,Sr,Ra)[SO<sub>4</sub>], may exist in natural conditions. Our fundamental understanding of the dissolution kinetics of isostructural sulfates is critically important for a better risk assessment of nuclear waste repositories utilizing this mineral for sequestration. So far, the barite-water interface has been studied with experimental methods and atomistic computer simulations. The direct connection between the molecular scale details of the interface structure and experimental observations at the microscopic scale is not yet well understood. Here, we began to investigate this connection by using a kinetic Monte Carlo approach to simulate the barite dissolution process. We constructed a microkinetic model for the dissolution process and identified the reactive sites. Identification of these sites is important for an improved understanding of the dissolution, adsorption, and crystal growth mechanisms at the barite–water interface. We parameterized the molecular detachment rates by using the experimentally observed etch pit morphologies and atomic step velocities. Our parameterization attempts demonstrated that local lattice coordination is not sufficient to differentiate between the kinetically important sites and estimate their detachment rates. We suggest that the water structure and dynamics at identified sites should substantially influence the detachment rates. However, it will require more work to improve the parameterization of the model by means of Molecular Dynamics and ab initio calculations. |
| first_indexed | 2024-03-10T03:20:53Z |
| format | Article |
| id | doaj.art-37d13bed03fc4fe49832aae43782a00e |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T03:20:53Z |
| publishDate | 2022-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-37d13bed03fc4fe49832aae43782a00e2023-11-23T12:19:51ZengMDPI AGMinerals2075-163X2022-05-0112563910.3390/min12050639A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site GeometryInna Kurganskaya0Nikolay Trofimov1Andreas Luttge2Geology Department (FB5), University of Bremen, Klagenfurter Str. 4, 28359 Bremen, GermanyGeology Department (FB5), University of Bremen, Klagenfurter Str. 4, 28359 Bremen, GermanyGeology Department (FB5), University of Bremen, Klagenfurter Str. 4, 28359 Bremen, GermanyBarite (Ba[SO<sub>4</sub>]) is one of the promising candidates for sequestration of radioactive waste. Barite can incorporate radium (Ra) and form ideal solid solutions, i.e., (Ba,Ra)[SO<sub>4</sub>]. Together with isostructural celestite (Sr[SO<sub>4</sub>]), ternary solid solutions, (Ba,Sr,Ra)[SO<sub>4</sub>], may exist in natural conditions. Our fundamental understanding of the dissolution kinetics of isostructural sulfates is critically important for a better risk assessment of nuclear waste repositories utilizing this mineral for sequestration. So far, the barite-water interface has been studied with experimental methods and atomistic computer simulations. The direct connection between the molecular scale details of the interface structure and experimental observations at the microscopic scale is not yet well understood. Here, we began to investigate this connection by using a kinetic Monte Carlo approach to simulate the barite dissolution process. We constructed a microkinetic model for the dissolution process and identified the reactive sites. Identification of these sites is important for an improved understanding of the dissolution, adsorption, and crystal growth mechanisms at the barite–water interface. We parameterized the molecular detachment rates by using the experimentally observed etch pit morphologies and atomic step velocities. Our parameterization attempts demonstrated that local lattice coordination is not sufficient to differentiate between the kinetically important sites and estimate their detachment rates. We suggest that the water structure and dynamics at identified sites should substantially influence the detachment rates. However, it will require more work to improve the parameterization of the model by means of Molecular Dynamics and ab initio calculations.https://www.mdpi.com/2075-163X/12/5/639kineticsmineral-water interfaceetch pitsbaritesulfatesMonte Carlo |
| spellingShingle | Inna Kurganskaya Nikolay Trofimov Andreas Luttge A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site Geometry Minerals kinetics mineral-water interface etch pits barite sulfates Monte Carlo |
| title | A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site Geometry |
| title_full | A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site Geometry |
| title_fullStr | A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site Geometry |
| title_full_unstemmed | A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site Geometry |
| title_short | A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site Geometry |
| title_sort | kinetic monte carlo approach to model barite dissolution the role of reactive site geometry |
| topic | kinetics mineral-water interface etch pits barite sulfates Monte Carlo |
| url | https://www.mdpi.com/2075-163X/12/5/639 |
| work_keys_str_mv | AT innakurganskaya akineticmontecarloapproachtomodelbaritedissolutiontheroleofreactivesitegeometry AT nikolaytrofimov akineticmontecarloapproachtomodelbaritedissolutiontheroleofreactivesitegeometry AT andreasluttge akineticmontecarloapproachtomodelbaritedissolutiontheroleofreactivesitegeometry AT innakurganskaya kineticmontecarloapproachtomodelbaritedissolutiontheroleofreactivesitegeometry AT nikolaytrofimov kineticmontecarloapproachtomodelbaritedissolutiontheroleofreactivesitegeometry AT andreasluttge kineticmontecarloapproachtomodelbaritedissolutiontheroleofreactivesitegeometry |