Ternary uranyl-citrate-surface complex formation on geothite gibbsite, and phylosilicate minerals

Conference · Tue Oct 01 04:00:00 EDT 1996

OSTI ID:370507

Redden, G D; Li, J; Leckie, J O ^[1]

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1. Stanford Univ., CA (United States)

Liquid radioactive wastes that contain transuranic elements are often associated with complexing organic co-contaminants. Prediction of radionuclide transpose in contaminated groundwater will require accounting for the effect of both organic co-solutes and naturally occurring compounds. A study has been conducted on the adsorption of uranyl ion (UO{sub 2}{sup 2+}) on goethite, gibbsite, and phylosilicate minerals in the presence of varying concentrations of citric acid. Adsorption of either solute separately as functions of pH yield sorption curves that are generally typical for cations and anions with differences in features reflecting differences in properties of the surface functional groups. At equimolar concentrations of uranyl and citrate little effect on the sorption of either solute is observed. However, at higher citrate concentrations uranyl sorption dramatically increases with nearly complete uranyl sorption even at relatively low pH values. A stable bridging structure involving uranyl and citrate is implied. These results have significant relevance to radionuclide transport modeling where soluble chelators may increase rather than decrease sorption of uranyl.

• OSTI ID: 370507
• Report Number(s): CONF-960376--
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
54 ENVIRONMENTAL SCIENCES
ADSORPTION
ANIONS
CITRIC ACID
COMPLEXES
GIBBSITE
GOETHITE
MINERALS
PH VALUE
RADIOACTIVE WASTES
RADIONUCLIDE MIGRATION
SOILS
SORPTIVE PROPERTIES
SURFACES
URANIUM DIOXIDE