A model-based evaluation of sorptive reactivities of hydrous ferric oxide and hematite for U(VI)

Je Hun Jang; Brian A. Dempsey; William D. Burgos

doi:10.1021/es070068f

A model-based evaluation of sorptive reactivities of hydrous ferric oxide and hematite for U(VI)

Je Hun Jang, Brian A. Dempsey, William D. Burgos

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60 Scopus citations

Abstract

The sorption of uranyl onto hydrous ferric oxide (HFO) or hematite was measured by discontinuously titrating the suspensions with uranyl at pH 5.9, 6.8, and 7.8 under P_CO2 = 10^-3.5atm (sorption isotherms). Batch reactors were used with equilibration times up to 48 days. Sorption of 1 μM uranyl onto HFO was also measured versus pH (sorption edge). A diffuse double layer surface complexation model was calibrated by invoking three sorption species that were consistent with spectroscopic evidence for predominance of bidentate complexes at neutral pH and uranyl-carbonato complexes: >SOH:UO₂OH⁺ (>SO)₂: UO ₂CO₃^-2, and (>SO)₂:(UO ₂)₃(OH)₅^-1. The model was consistent with previously published isotherm and edge data. The model successfully predicted sorption data onto hematite, only adjusting for different measured specific surface area. Success in application of the model to hematite indicates that the hydrated surface of hematite has similar sorptive reactivity as HFO.

Original language	English (US)
Pages (from-to)	4305-4310
Number of pages	6
Journal	Environmental Science and Technology
Volume	41
Issue number	12
DOIs	https://doi.org/10.1021/es070068f
State	Published - Jun 15 2007

All Science Journal Classification (ASJC) codes

General Chemistry
Environmental Chemistry

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10.1021/es070068f

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title = "A model-based evaluation of sorptive reactivities of hydrous ferric oxide and hematite for U(VI)",

abstract = "The sorption of uranyl onto hydrous ferric oxide (HFO) or hematite was measured by discontinuously titrating the suspensions with uranyl at pH 5.9, 6.8, and 7.8 under PCO2 = 10-3.5atm (sorption isotherms). Batch reactors were used with equilibration times up to 48 days. Sorption of 1 μM uranyl onto HFO was also measured versus pH (sorption edge). A diffuse double layer surface complexation model was calibrated by invoking three sorption species that were consistent with spectroscopic evidence for predominance of bidentate complexes at neutral pH and uranyl-carbonato complexes: >SOH:UO2OH+ (>SO)2: UO 2CO3-2, and (>SO)2:(UO 2)3(OH)5-1. The model was consistent with previously published isotherm and edge data. The model successfully predicted sorption data onto hematite, only adjusting for different measured specific surface area. Success in application of the model to hematite indicates that the hydrated surface of hematite has similar sorptive reactivity as HFO.",

author = "Jang, {Je Hun} and Dempsey, {Brian A.} and Burgos, {William D.}",

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AU - Jang, Je Hun

AU - Dempsey, Brian A.

AU - Burgos, William D.

PY - 2007/6/15

Y1 - 2007/6/15

N2 - The sorption of uranyl onto hydrous ferric oxide (HFO) or hematite was measured by discontinuously titrating the suspensions with uranyl at pH 5.9, 6.8, and 7.8 under PCO2 = 10-3.5atm (sorption isotherms). Batch reactors were used with equilibration times up to 48 days. Sorption of 1 μM uranyl onto HFO was also measured versus pH (sorption edge). A diffuse double layer surface complexation model was calibrated by invoking three sorption species that were consistent with spectroscopic evidence for predominance of bidentate complexes at neutral pH and uranyl-carbonato complexes: >SOH:UO2OH+ (>SO)2: UO 2CO3-2, and (>SO)2:(UO 2)3(OH)5-1. The model was consistent with previously published isotherm and edge data. The model successfully predicted sorption data onto hematite, only adjusting for different measured specific surface area. Success in application of the model to hematite indicates that the hydrated surface of hematite has similar sorptive reactivity as HFO.

AB - The sorption of uranyl onto hydrous ferric oxide (HFO) or hematite was measured by discontinuously titrating the suspensions with uranyl at pH 5.9, 6.8, and 7.8 under PCO2 = 10-3.5atm (sorption isotherms). Batch reactors were used with equilibration times up to 48 days. Sorption of 1 μM uranyl onto HFO was also measured versus pH (sorption edge). A diffuse double layer surface complexation model was calibrated by invoking three sorption species that were consistent with spectroscopic evidence for predominance of bidentate complexes at neutral pH and uranyl-carbonato complexes: >SOH:UO2OH+ (>SO)2: UO 2CO3-2, and (>SO)2:(UO 2)3(OH)5-1. The model was consistent with previously published isotherm and edge data. The model successfully predicted sorption data onto hematite, only adjusting for different measured specific surface area. Success in application of the model to hematite indicates that the hydrated surface of hematite has similar sorptive reactivity as HFO.

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A model-based evaluation of sorptive reactivities of hydrous ferric oxide and hematite for U(VI)

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