Sorption of trace metals on calcite: applicability of the surface precipitation model
Published sorption isotherm data of Cd/sup 2 +/, Mn/sup 2 +/, Zn/sup 2 +/, and Co/sup 2 +/ on calcite are adequately described by the surface precipitation model which was originally developed by Farley et al. (1985) for the sorption of cations on metal oxides. In addition to monolayer adsorption, the model accounts for the formation of a surface phase with a composition that is described by a solid solution having as end members the sorbent calcium carbonate mineral and a pure carbonate precipitate of the sorbing trace metal. The model thus specifies a continuum between adsorption and precipitation. This feature is supported in the literature by observations on the reaction kinetics and the amount of surface coverage during trace metal sorption on calcite. The apparent adsorption constants of these trace metals, as derived from the model, can be ranked according to the degree to which their ionic radii match the ionic radius of Ca/sup 2 +/.
- Research Organization:
- Univ. of Utrecht (Netherlands)
- OSTI ID:
- 5064640
- Journal Information:
- Geochim. Cosmochim. Acta; (United States), Journal Name: Geochim. Cosmochim. Acta; (United States) Vol. 51:9; ISSN GCACA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580400* -- Geochemistry-- (-1989)
ADSORPTION
ALKALINE EARTH METAL COMPOUNDS
CADMIUM COMPOUNDS
CADMIUM IONS
CADMIUM OXIDES
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTION KINETICS
CHEMISTRY
COBALT COMPOUNDS
COBALT IONS
COBALT OXIDES
GEOCHEMISTRY
GEOLOGIC MODELS
IONS
KINETICS
MANGANESE COMPOUNDS
MANGANESE IONS
MANGANESE OXIDES
MINERALS
OXIDES
OXYGEN COMPOUNDS
PRECIPITATION
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SURFACE AREA
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
ZINC COMPOUNDS
ZINC IONS
ZINC OXIDES