Selenium sorption by kaolinite and montmorillonite

Journal Article · Wed Jul 01 04:00:00 EDT 1987 · Soil Sci.; (United States)

DOI:https://doi.org/10.1097/00010694-198707000-00003· OSTI ID:5319132

Bar-Yosef, B; Meek, D

Toxic selenium (Se) concentrations were found recently in shallow ground water on the west side of the San Joaquin Valley in California. The origin of the Se and the mechanism by which it accumulated in the ground water are not known. The objective of this work was to study Se sorption by kaolinite and montmorillonite at different pH levels, as a model of Se sorption reactions in soils, and evaluate the role of adsorption in distributing Se between solution and solid phases of soils. Within an Se concentration range of 0 to about 12 ..mu..mol/L and pHs between 4 and 8, which cover the pH and Se concentrations in most affected drainage water, Se solubility in the studied suspensions was governed by adsorption. The sorption kinetics were best described by the Elovich equation. The adsorption decreased with elevating pH values and became negligible above pH 8. A modified competitive Langmuir model simulated satisfactorily Se retention by the two adsorbents under the studied experimental conditions. The greater adsorption of Se/sup 4/ than Se/sup 6/ by kaolinite and the different relative adsorption of Se/sup 4/ by kaolinite and montmorillonite above and below pH 7 were expressed in terms of model parameters. Hydroxyl ions were more effective in modifying the anions' adsorption capacity than competing with Se on common adsorption sites.

• Research Organization: Dept. of Agriculture, Fresno, CA (USA)
• OSTI ID: 5319132
• Journal Information: Soil Sci.; (United States), Journal Name: Soil Sci.; (United States) Vol. 144:1; ISSN SOSCA
• Country of Publication: United States
• Language: English

Related Subjects

510100* -- Environment
Terrestrial-- Basic Studies-- (-1989)
520200 -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ADSORPTION
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
ANIONS
CALIFORNIA
CHARGED PARTICLES
CLAYS
ECOLOGICAL CONCENTRATION
ELEMENTS
ENVIRONMENTAL TRANSPORT
EQUATIONS
FEDERAL REGION IX
GROUND WATER
HYDROGEN COMPOUNDS
HYDROXIDES
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IONS
KAOLINITE
KINETIC EQUATIONS
MASS TRANSFER
MATERIALS
MINERALS
MONTMORILLONITE
NORTH AMERICA
OXYGEN COMPOUNDS
PH VALUE
PHASE STUDIES
POLLUTION
RESPONSE MODIFYING FACTORS
SELENIUM
SEMIMETALS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
USA
VALENCE
WATER
WATER POLLUTION