Selenate Adsorption on Alluvial Soils
- Rosemary H. Neal and
- Garrison Sposito
The adsorption of selenate by four alluvial soils from the San Joaquin Valley, CA, was investigated under conditions of varying pH and equilibrating solution composition. Soil samples were prepared in the form of Na-saturated pastes. Adsorption experiments were carried out in 50 mol m−3 NaCl or NaClO4 background solution at initial selenate concentrations comparable to those found in field soils (5 mmol kg−1). The pH value and electrode potential (Eh) were monitored while the reaction mixtures were equilibrated using CO2-free air for stirring in a constant temperature apparatus. In contrast to the results obtained previously for selenite, positive selenate adsorption by the four soils was not detected over the pH range of 5.5 to 9 in either the NaCl or NaClO4 electrolyte background. Selenate was found to behave in a manner similar to sulfate in these soils, but was not negatively adsorbed to the extent exhibited by chloride.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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