Metal cation/anion adsorption on calcium carbonate: Implications to metal ion concentrations in groundwater
This chapter evaluates the sorption behavior of metallic ions on specimen calcite as a basis for determining the importance of calcite relative to other subsurface sorbents, such as layer silicates and oxides, in controlling metal ion concentration in calcareous groundwaters. A review of the literature shows the sorption of both metallic cations and anions on calcite over ranges in pH and CO{sub 2} partial pressure to be consistent with a surface-exchange process where cations exchange with surface Ca and anions exchange with surface CO{sub 3}. A general surface-exchange model was developed to account for the effects of Ca and CO{sub 3} concentrations, pH, and calcite surface area on cation and anion sorption onto calcite. The model was applied to recently developed experimental sorption data of Zn and SeO{sub 3} on specimen calcite in equilibrium CaCO{sub 3}(aq) suspensions. The surface-exchange model was able to describe the effects of pH on both cation and anion sorption, and provided good predictions of the effects of variable CO{sub 2}(g) pressure on Zn sorption and of PO{sub 4} on SeO{sub 3} sorption. The surface-exchange model, combined with sorption constants for other phases, was used to calculate Cd sorption to a hypothetical aquifer material containing a mixture of sorbents. The sorbent concentrations were fixed to those expected in groundwater zones. The multi-sorbent calculation documented the importance of calcite as a sorbent for metallic ions in groundwater.93 refs., 18 figs., 5 tabs.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (USA)
- Sponsoring Organization:
- DOE/ER; EPRI
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 6279318
- Report Number(s):
- PNL-SA-18360; CONF-8905356--1; ON: DE91005611; CNN: RP2485-03
- Country of Publication:
- United States
- Language:
- English
Similar Records
Solution ion effects on the surface exchange of selenite on calcite
The mechanism of Zn sup 2+ adsorption on calcite
Related Subjects
540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
ADSORPTION
ALKALINE EARTH METAL COMPOUNDS
ANIONS
CADMIUM
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CATIONS
CHARGED PARTICLES
CONTAMINATION
DATA
ECOLOGICAL CONCENTRATION
ELEMENTS
EXPERIMENTAL DATA
GROUND WATER
HYDROGEN COMPOUNDS
INFORMATION
IONS
MANAGEMENT
MATERIALS RECOVERY
MATHEMATICAL MODELS
METALS
MINERALS
NUMERICAL DATA
OXYGEN COMPOUNDS
PH VALUE
POLLUTION
PROCESSING
RECOVERY
SELENIUM COMPOUNDS
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
WASTE MANAGEMENT
WASTE PROCESSING
WATER
WATER POLLUTION
ZINC COMPOUNDS