Surface complexation model of uranyl sorption on Georgia kaolinite

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dc.contributor.authorPayne, TEen_AU
dc.contributor.authorDavis, JAen_AU
dc.contributor.authorLumpkin, GRen_AU
dc.contributor.authorChisari, Ren_AU
dc.contributor.authorWaite, TDen_AU
dc.date.accessioned2025-01-09T01:43:59Zen_AU
dc.date.available2025-01-09T01:43:59Zen_AU
dc.date.issued2004-08en_AU
dc.date.statistics2024-08-09en_AU
dc.description.abstractThe adsorption of uranyl on standard Georgia kaolinites (KGa-1 and KGa-1B) was studied as a function of pH (3-10), total U (1 and 10 μmol/l), and mass loading of clay (4 and 40 g/l). The uptake of uranyl in air-equilibrated systems increased with pH and reached a maximum in the near-neutral pH range. At higher pH values, the sorption decreased due to the presence of aqueous uranyl carbonate complexes. One kaolinite sample was examined after the uranyl uptake experiments by transmission electron microscopy (TEM), using energy dispersive X-ray spectroscopy (EDS) to determine the U content. It was found that uranium was preferentially adsorbed by Ti-rich impurity phases (predominantly anatase), which are present in the kaolinite samples. Uranyl sorption on the Georgia kaolinites was simulated with U sorption reactions on both titanol and aluminol sites, using a simple non-electrostatic surface complexation model (SCM). The relative amounts of U-binding >TiOH and >AlOH sites were estimated from the TEM/EDS results. A ternary uranyl carbonate complex on the titanol site improved the fit to the experimental data in the higher pH range. The final model contained only three optimised log K values, and was able to simulate adsorption data across a wide range of experimental conditions. The >TiOH (anatase) sites appear to play an important role in retaining U at low uranyl concentrations. As kaolinite often contains trace TiO2, its presence may need to be taken into account when modelling the results of sorption experiments with radionuclides or trace metals on kaolinite. © 2004 Elsevier B.V.en_AU
dc.identifier.citationPayne, T. E., Davis, J. A., Lumpkin, G. R., Chisari, R., & Waite, T. D. (2004). Surface complexation model of uranyl sorption on Georgia kaolinite. Applied Clay Science, 26(1), 151-162. doi:10.1016/j.clay.2003.08.013en_AU
dc.identifier.issn0169-1317en_AU
dc.identifier.issue1-4en_AU
dc.identifier.pagination151-162en_AU
dc.identifier.urihttps://doi.org/10.1016/j.clay.2003.08.013en_AU
dc.identifier.urihttps://apo.ansto.gov.au/handle/10238/15858en_AU
dc.identifier.volume26en_AU
dc.languageEnglishen_AU
dc.language.isoenen_AU
dc.publisherElsevieren_AU
dc.subjectSorptionen_AU
dc.subjectpH Valueen_AU
dc.subjectKaoliniteen_AU
dc.subjectTransmission electron microscopyen_AU
dc.subjectSpectroscopyen_AU
dc.subjectUraniumen_AU
dc.subjectTitaniumen_AU
dc.subjectSoilsen_AU
dc.subjectContaminationen_AU
dc.subjectEnvironmenten_AU
dc.subjectAdsorptionen_AU
dc.titleSurface complexation model of uranyl sorption on Georgia kaoliniteen_AU
dc.typeBooken_AU
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