Aqueous solubility diagrams for cementitious waste stabilization systems. 4. A carbonation model for Zn-doped calcium silicate hydrate by Gibbs energy minimization

Publication type:
Journal article
Metadata:
Autoren
Autoren-URL
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=fis-test-1&SrcAuth=WosAPI&KeyUT=WOS:000176591600037&DestLinkType=FullRecord&DestApp=WOS_CPL
DOI
10.1021/es010250v
eISSN
1520-5851
Externe Identifier
  • Clarivate Analytics Document Solution ID: 569GA
  • PubMed Identifier: 12144269
ISSN
0013-936X
Ausgabe der Veröffentlichung
13
Zeitschrift
ENVIRONMENTAL SCIENCE & TECHNOLOGY
Paginierung
2926 - 2931
Datum der Veröffentlichung
2002
Status
Published
Titel
Aqueous solubility diagrams for cementitious waste stabilization systems. 4. A carbonation model for Zn-doped calcium silicate hydrate by Gibbs energy minimization
Sub types
  • Article
Ausgabe der Zeitschrift
36

Data source: Web of Science (Lite)

Other metadata sources:
Autoren
DOI
10.1021/es010250v
eISSN
1520-5851
ISSN
0013-936X
Ausgabe der Veröffentlichung
13
Zeitschrift
Environmental Science & Technology
Sprache
en
Online publication date
2002
Paginierung
2926 - 2931
Datum der Veröffentlichung
2002
Status
Published
Herausgeber
American Chemical Society (ACS)
Herausgeber URL
http://dx.doi.org/10.1021/es010250v
Datum der Datenerfassung
2023
Titel
Aqueous Solubility Diagrams for Cementitious Waste Stabilization Systems. 4. A Carbonation Model for Zn-Doped Calcium Silicate Hydrate by Gibbs Energy Minimization
Ausgabe der Zeitschrift
36

Data source: Crossref

Abstract
A thermodynamic Gibbs energy minimization (GEM) solid solution-aqueous solution (SSAS) equilibrium model was used to determine the solubility of Zn from calcium silicate hydrate (CSH) phases doped with 0, 0.1, 1, 5, and 10% Zn at a unity (Ca+Zn)/Si molar ratio. Both the stoichiometry and standard molar Gibbs energy (G(o)298) of the Zn-bearing end-member in the ideal ternary Zn-bearing calcium silicate hydrate (CZSH) solid solution were determined by a "dual-thermodynamic" (GEM-DT) estimation technique. The SSAS model reproduces a complex sequence of reactions suggested to occur in a long-term weathering scenario of cementitious waste forms at subsurface repository conditions. The GEM model of CZSH leaching at several Zn loadings and solid/water (s/w) ratios in a C02-free system showed that, upon complete dissolution of portlandite and calcium zincate phases at decreasing s/w < 0.01 mol x kg(H2O)(-1), the total dissolved concentrations Si(aq), Ca(aq), and Zn(aq) are controlled by a CZSH solid solution of changing composition, with a trough-like Znaq drop by 2-3 orders of magnitude. Carbonation was simulated in another GEM model run series by CO2 titration of the system with initial s/w approximately 0.9 mol/kg(H2O). Formation of (Ca,Zn)-CO3 nonideal solid solution was predicted already at early reaction stage in the presence of both portlandite and calcium zincate hydrate phases. Upon their disappearance, pH, Zn(aq), C(aq), and fCO2 were predicted to change due to the incongruent dissolution of two concurrent CZSH-I and CZSH-II solid solutions, until the total re-partitioning of Ca and Zn into a carbonate solid solution coexisting with amorphous silica at fCO2 > 0.1 bar. Along this solid-phase transition, dissolved Zn(aq) concentrations follow a highly nonlinear trend. The model results predict that at low to moderate Zn loading (< or = 1% per mole Si), CZSH-type compounds can efficiently immobilize Zn in the near field of a cement-stabilized waste repository.
Addresses
  • Waste Management Laboratory, Paul Scherrer Institute, Villigen PSI, Switzerland.
Autoren
DOI
10.1021/es010250v
eISSN
1520-5851
Externe Identifier
  • PubMed Identifier: 12144269
Open access
false
ISSN
0013-936X
Ausgabe der Veröffentlichung
13
Zeitschrift
Environmental science & technology
Schlüsselwörter
  • Calcium Compounds
  • Zinc
  • Silicates
  • Environmental Pollution
  • Refuse Disposal
  • Solubility
  • Thermodynamics
  • Models, Theoretical
  • Manufactured Materials
Sprache
eng
Medium
Print
Paginierung
2926 - 2931
Datum der Veröffentlichung
2002
Status
Published
Datum der Datenerfassung
2002
Titel
Aqueous solubility diagrams for cementitious waste stabilization systems. 4. A carbonation model for Zn-doped calcium silicate hydrate by Gibbs energy minimization.
Sub types
  • Research Support, Non-U.S. Gov't
  • Journal Article
Ausgabe der Zeitschrift
36

Data source: Europe PubMed Central

Abstract
A thermodynamic Gibbs energy minimization (GEM) solid solution-aqueous solution (SSAS) equilibrium model was used to determine the solubility of Zn from calcium silicate hydrate (CSH) phases doped with 0, 0.1, 1, 5, and 10% Zn at a unity (Ca+Zn)/Si molar ratio. Both the stoichiometry and standard molar Gibbs energy (G(o)298) of the Zn-bearing end-member in the ideal ternary Zn-bearing calcium silicate hydrate (CZSH) solid solution were determined by a "dual-thermodynamic" (GEM-DT) estimation technique. The SSAS model reproduces a complex sequence of reactions suggested to occur in a long-term weathering scenario of cementitious waste forms at subsurface repository conditions. The GEM model of CZSH leaching at several Zn loadings and solid/water (s/w) ratios in a C02-free system showed that, upon complete dissolution of portlandite and calcium zincate phases at decreasing s/w < 0.01 mol x kg(H2O)(-1), the total dissolved concentrations Si(aq), Ca(aq), and Zn(aq) are controlled by a CZSH solid solution of changing composition, with a trough-like Znaq drop by 2-3 orders of magnitude. Carbonation was simulated in another GEM model run series by CO2 titration of the system with initial s/w approximately 0.9 mol/kg(H2O). Formation of (Ca,Zn)-CO3 nonideal solid solution was predicted already at early reaction stage in the presence of both portlandite and calcium zincate hydrate phases. Upon their disappearance, pH, Zn(aq), C(aq), and fCO2 were predicted to change due to the incongruent dissolution of two concurrent CZSH-I and CZSH-II solid solutions, until the total re-partitioning of Ca and Zn into a carbonate solid solution coexisting with amorphous silica at fCO2 > 0.1 bar. Along this solid-phase transition, dissolved Zn(aq) concentrations follow a highly nonlinear trend. The model results predict that at low to moderate Zn loading (< or = 1% per mole Si), CZSH-type compounds can efficiently immobilize Zn in the near field of a cement-stabilized waste repository.
Autoren
Autoren-URL
https://www.ncbi.nlm.nih.gov/pubmed/12144269
DOI
10.1021/es010250v
ISSN
0013-936X
Ausgabe der Veröffentlichung
13
Zeitschrift
Environ Sci Technol
Schlüsselwörter
  • Calcium Compounds
  • Environmental Pollution
  • Manufactured Materials
  • Models, Theoretical
  • Refuse Disposal
  • Silicates
  • Solubility
  • Thermodynamics
  • Zinc
Sprache
eng
Country
United States
Paginierung
2926 - 2931
Datum der Veröffentlichung
2002
Status
Published
Datum, an dem der Datensatz öffentlich gemacht wurde
2003
Titel
Aqueous solubility diagrams for cementitious waste stabilization systems. 4. A carbonation model for Zn-doped calcium silicate hydrate by Gibbs energy minimization.
Sub types
  • Journal Article
  • Research Support, Non-U.S. Gov't
Ausgabe der Zeitschrift
36

Data source: PubMed

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