Towards an understanding of the sorption of U(VI) and Se(IV) on sodium bentonite

Boult, K. A.; Cowper, M. M.; Heath, Timothy G.; Sato, Haruo; Shibutani, Tomoki; Yui, Mikazu

doi:10.1016/s0169-7722(98)00122-3

Cited by 72 publications

(33 citation statements)

References 9 publications

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“…In Figure 1 The sorption tendency was also in agreement with the previous one [12]. The dominant sorption mechanism of Se(IV) onto goethite has been reported to be innersphere surface complexation [12,52,69]. The results of the current study can also be explained by inner-sphere surface complexation.…”

Section: Sorption Behavior Of Se(iv)supporting

confidence: 89%

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Sorption behavior of hydroselenide (HSe⁻) onto iron-containing minerals

Iida

Yamaguchi

Tanaka

2013

Journal of Nuclear Science and Technology

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The sorption behavior of selenium onto iron-containing minerals such as goethite, ferrous oxide, magnetite, and biotite under reducing conditions were investigated by batch sorption experiments. Selenium was spiked as HSe − and Se 4 2− in the experimental solutions and reducing conditions were maintained throughout the sorption periods. The sorption behaviors of HSe − were analyzed by the triple-layer surface complexation model with the Visual Minteq computer program. The sorption data and the model calculations suggested that the dominant sorption mechanisms of HSe − were inner-sphere surface complexation for goethite and ferrous oxide but outer-sphere surface complexation for magnetite and biotite. The intrinsic equilibrium constant of the inner-sphere surface complexation reaction of HSe − with goethite, logK int HSe = 6.0, was determined by the fitting to the experimental results. The value of the equilibrium constant for outer-sphere complexation for magnetite and biotite was estimated to be around 12.

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Section: Sorption Behavior Of Se(iv)supporting

confidence: 89%

“…The sorption of Se(IV) onto ≡FeOH sites can be described as inner-sphere surface complexation [12,22,27,52,69]. Biotite includes aluminol (≡AlOH) and silanol (≡SiOH) sites on the edge surfaces, in addition to ≡FeOH sites [3].…”

Section: Sorption Behavior Of Se (Iv)mentioning

confidence: 99%

Sorption behavior of hydroselenide (HSe⁻) onto iron-containing minerals

Iida

Yamaguchi

Tanaka

2013

Journal of Nuclear Science and Technology

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“…The macroscopic adsorption of Se(IV) was predicted using the data from Boult et al (1998) in 10 mM NaCl (Fig. 3).…”

mentioning

confidence: 99%

Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay

Charlet

Scheinost²,

Tournassat

et al. 2007

Geochimica et Cosmochimica Acta

183

129

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Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay. Geochimica et Cosmochimica Acta, Elsevier, 2007, 71 (23) , selenite was sorbed as outer-sphere sorption complex, covering only part of the positive edge sites, as verified by a structure-based MUSIC model and Se K-edge XAS (X-ray absorption spectroscopy). When selenite was added to montmorillonite previously equilibrated with Fe 2+ solution however, slow reduction of Se and formation of a solid phase was observed with Se K-edge XANES (x-ray absorption near-edge spectroscopy) and EXAFS (extended x-ray absorption finestructure) spectroscopy. Iterative transformation factor analysis of XANES and EXAFS spectra suggested that only one Se reaction product formed, which was identified as nano-particulate Se(0). Even after one month, only 75% of the initially sorbed Se(IV) was reduced to this solid species. Mössbauer spectrometry revealed that before and after addition and reduction of Se, 5% of total sorbed Fe occurred as

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“…K d values exceeded 10 5 in the pH range of 6 though 8 but decreased as pH increased above 9. The decrease in U sorption above pH 9 is likely the result uranyl carbonate formation that has been documented to strongly affect sorption of uranium (Boult et al, 1998;). Interestingly, the sorption of U by the synthetic hydroxyapatite was less sensitive to pH than the bovine apatites.…”

Section: Sorption Experimentsmentioning

confidence: 98%

Containment of uranium in the proposed Egyptian geologic repository for radioactive waste using hydroxyapatite.

Moore¹,

Hasan²,

Headley³

et al. 2004

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Currently, the Egyptian Atomic Energy Authority is designing a shallow-land disposal facility for low-level radioactive waste. To insure containment and prevent migration of radionuclides from the site, the use of a reactive backfill material is being considered. One material under consideration is hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 , which has a high affinity for the sorption of many radionuclides. Hydroxyapatite has many properties that make it an ideal material for use as a backfill including low water solubility (K sp >10 -40 ), high stability under reducing and oxidizing conditions over a wide temperature range, availability, and low cost. However, there is often considerable variation in the properties of apatites depending on source and method of preparation. In this work, we characterized and compared a synthetic hydroxyapatite with hydroxyapatites prepared from cattle bone calcined at 500°C, 700°C, 900°C and 1100°C. The analysis indicated the synthetic hydroxyapatite was similar in morphology to 500°C prepared cattle hydroxyapatite. With increasing calcination temperature the crystallinity and crystal size of the hydroxyapatites increased and the BET surface area and carbonate concentration decreased. Batch sorption experiments were performed to determine the effectiveness of each material to sorb uranium. Sorption of U was strong regardless of apatite type indicating all apatite materials evaluated. Sixty day desorption experiments indicated desorption of uranium for each hydroxyapatite was negligible. 4Intentionally Left Blank 5

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Towards an understanding of the sorption of U(VI) and Se(IV) on sodium bentonite

Cited by 72 publications

References 9 publications

Sorption behavior of hydroselenide (HSe⁻) onto iron-containing minerals

Sorption behavior of hydroselenide (HSe⁻) onto iron-containing minerals

Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay

Containment of uranium in the proposed Egyptian geologic repository for radioactive waste using hydroxyapatite.

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Towards an understanding of the sorption of U(VI) and Se(IV) on sodium bentonite

Cited by 72 publications

References 9 publications

Sorption behavior of hydroselenide (HSe−) onto iron-containing minerals

Sorption behavior of hydroselenide (HSe−) onto iron-containing minerals

Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay

Containment of uranium in the proposed Egyptian geologic repository for radioactive waste using hydroxyapatite.

Contact Info

Product

Resources

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Sorption behavior of hydroselenide (HSe⁻) onto iron-containing minerals

Sorption behavior of hydroselenide (HSe⁻) onto iron-containing minerals