Journal article
The energetics of nanophase calcite
Geochimica et cosmochimica acta, Vol.75(24), pp.7893-7905
2011
DOI: 10.1016/j.gca.2011.09.034
Abstract
Calcium carbonate (CaCO 3) is an important component of the near-surface environment. Understanding the nature of its precipitation is important for a variety of environmental processes, as well as for the geologic sequestration of anthropogenic carbon dioxide. Calcite is the most thermodynamically stable bulk polymorph, but energy crossovers may exist that could favor the precipitation of vaterite or aragonite with decreasing particle size. The purpose of this study is to determine the surface energy of calcite, which is the first step towards understanding the effect of particle size on thermodynamic stability in the calcium carbonate system. The enthalpies of five well-characterized calcite samples (four nanophase and one bulk) were measured by acid solution isothermal and water adsorption calorimetric techniques. From the calorimetric data, the surface energies of calcite were determined to be 1.48 ± 0.21 and 1.87 ± 0.16 J/m 2 for hydrous and anhydrous surfaces. These values are similar to those measured for many oxides but larger than predicted from computational models for idealized calcite surfaces. The surfaces of synthetic CaCO 3 particles contain a range of planes and defect structures, which may give rise to the difference between the experimental and modeled values.
Details
- Title: Subtitle
- The energetics of nanophase calcite
- Creators
- Tori Z ForbesA.V RadhaAlexandra Navrotsky
- Resource Type
- Journal article
- Publication Details
- Geochimica et cosmochimica acta, Vol.75(24), pp.7893-7905
- Publisher
- Elsevier Ltd
- DOI
- 10.1016/j.gca.2011.09.034
- ISSN
- 0016-7037
- eISSN
- 1872-9533
- Language
- English
- Date published
- 2011
- Academic Unit
- Chemistry; Civil and Environmental Engineering
- Record Identifier
- 9983985983702771
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