Radionuclides in the Geosphere: Sources, Mobility, Reactions in Natural Waters and Interactions with Solids

Lieser, Κ. H.

doi:10.1524/ract.1995.7071.special-issue.355

Cited by 91 publications

(35 citation statements)

References 140 publications

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“…From radioactive waste management view point, 90 Sr (t 1/2 = 29.1 y) possesses a particular importance due to its long half life and high yield (5.77%) during fission [1]. Various studies have been carried out to examine different aspects of the sorption behavior of Sr on a variety of solid materials [2][3][4][5][6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Sr²⁺uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

Shahwan¹,

Erten²

2005

Radiochimica Acta

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Sr2+ / Kaolinite / Magnesite Summary. The sorption behavior of Sr 2+ ions on natural minerals rich in kaolinite and magnesite was studied using SEM/EDS, XPS, XRPD, AAS/AES and DRIFT techniques. Quantitative analysis of the XPS data shows that magnesite is more effective in Sr 2+ uptake than kaolinite. DRIFT spectra and XRPD patterns indicate that the structures of both minerals were not affected upon Sr 2+ sorption. Intercalation of DMSO in kaolinite lamellae aiming at increasing the interlayer space did not significantly enhance the sorption capacity of the clay towards Sr 2+ probably due to the lack of a negative charge on the accessible sites. EDS mapping indicated that while the sorbed Sr is equally distributed on surface of natural kaolinite, it was associated -to a larger extent -with the regions richer in Mg in the case of natural magnesite. Comparing the uptake mechanisms of natural magnesite with that of pure MgCO 3 , it was seen that while natural magnesite sorbed Sr 2+ mainly through an ion exchange type mechanism, the formation of SrCO 3 coprecipitate was detected on the surface of the MgCO 3 at higher loadings.

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Section: Introductionmentioning

confidence: 99%

Characterization of Sr²⁺uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

Shahwan¹,

Erten²

2005

Radiochimica Acta

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“…Furthermore, Table 2 indicates that the total ESA of each of Ba 2+ and Co 2+ exceed the corresponding total EDA of the depleted ions. This probably indicates that, in addition to ion exchange, other sorption mechanisms might be operating, for example, incorporation of the sorbed ions in structural defects possessing permanent negative charge and hydrolytic sorption, which can be described by the following equation [7]:…”

Section: Resultsmentioning

confidence: 99%

ToF–SIMS depth profiling analysis of the uptake of Ba2+ and Co2+ ions by natural kaolinite clay

Shahwan

Erten

Black

et al. 2004

Journal of Colloid and Interface Science

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The sorption behavior of Ba 2+ and Co 2+ ions on a natural clay sample rich in kaolinite was studied using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Depth profiling at 10-Å steps was performed up to a 70-Å matrix depth of the clay prior to and following sorption. The results showed that Co 2+ is sorbed in slightly larger quantities than Ba 2+ , with significant numbers of ions fixed on the outermost surface of the clay. Depletion of the ions K + , Mg 2+ , and Ca 2+ from the clay lattice was observed to accompany enrichment with Co 2+ and Ba 2+ ions. The data obtained using X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM) indicated insignificant structural and morphological changes in the lattice of the clay upon sorption of both Ba 2+ and Co 2+ ions. Analysis using energy dispersive X-ray spectroscopy (EDS) showed that the average atomic percentage (±S.D.) of Ba and Co on kaolinite surface were 0.49 ± 0.11 and 0.61 ± 0.19, respectively, indicating a limited uptake capacity of natural kaolinite for both ions.

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“…Strontium is an element that possesses radioactive isotopes like 89 Sr (t 1/2 = 50.5 d) and 90 Sr (t 1/2 = 28.5 y), which are produced in high rates during the fission reactions and considered among the most important radionuclides from radioactive waste point of view (Lieser, 1995).…”

Section: Introductionmentioning

confidence: 99%

Study of the scavenging behavior and structural changes accompanying the interaction of aqueous Pb2+ and Sr2+ ions with calcite

2005

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The uptake of Pb 2+ and Sr 2+ ions from aqueous solutions by calcite was studied at various initial concentrations and pH conditions using the batch method under ambient conditions. XRPD, SEM/EDS, AAS/AES, and DRIFT techniques were used in characterizing the sorption process. The results indicated that the retention mechanism of Pb 2+ and Sr 2+ ions ranged from ion incorporation to precipitate overgrowth (cerussite, hydrocerussite for Pb, strontianite for Sr) depending on the concentration and pH conditions. The calcite structure seemed to be entirely vanishing upon formation of cerussite and hydrocerussite while partial dissolution of calcite occurred upon strontianite formation. The formation of precipitates showed rapid kinetics, and equilibrium seemed to be reached within about an hour from the start of mixing. SEM analysis showed that cerussite, hydrocerussite, and strontianite had columnar prismatic-like, tabular hexagonal-like, and needlelike morphologies. Based on a nine-month observation period, dry samples of hydrocerussite seemed to show more morphological stability than cerussite. EDS analysis indicated that Pb 2+ sorption is more favored than that of Sr 2+ , particularly in the phase of precipitate overgrowth. DRIFT analysis indicated a change in the symmetry of the carbonate groups in calcite matrix upon uptake of Pb 2+ and Sr 2+ cations.Keywords: calcite, Pb 2+ , Sr 2+ , strontianite, cerussite, hydrocerussite various metals and hence affecting the biogeochemical cycles of these metals in the environment. These minerals play a major rule in the chemical regulation of aquatic environments via precipitation, dissolution, and sorption reactions which are in turn controlled by the chemical processes taking place at the interface between the mineral lattice and the bulk solution (Morse, 1986). CaCO 3 can exist in three polymorphs; calcite, aragonite, and vaterite. Among these three polymorphs, calcite is the most thermodynamically stable one at room temperature and atmospheric pressure. Calcite possesses a rhombohedral/hexagonal structure with the trigonal carbonate ions being coplanar. The planes containing carbonate ions are perpendicular to the c-axis and they are rotated by 60° from one carbonate layer to the next (Kuriyavar et al., 2000).Knowledge of the nature of interaction of the metal ions with carbonate minerals is essential in predicting the extent to which they could be fated by these ions, the thing leading to retarding their dispersion into the environment. Recently, the increased applications of various surface-sensitive spectroscopic and microscopic techniques in sorption studies is enabling an understanding of this process on molecular-level the thing providing a better understanding of the mechanisms of interactions between different ions and sorbents. A limited number of such studies were devoted to characterizing the interac- INTRODUCTIONLead is an element that is continuously discharged into the biological environment as a result of various individual and industrial activities (g...

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Radionuclides in the Geosphere: Sources, Mobility, Reactions in Natural Waters and Interactions with Solids

Cited by 91 publications

References 140 publications

Characterization of Sr²⁺uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

Characterization of Sr²⁺uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

ToF–SIMS depth profiling analysis of the uptake of Ba2+ and Co2+ ions by natural kaolinite clay

Study of the scavenging behavior and structural changes accompanying the interaction of aqueous Pb2+ and Sr2+ ions with calcite

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Radionuclides in the Geosphere: Sources, Mobility, Reactions in Natural Waters and Interactions with Solids

Cited by 91 publications

References 140 publications

Characterization of Sr2+uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

Characterization of Sr2+uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

ToF–SIMS depth profiling analysis of the uptake of Ba2+ and Co2+ ions by natural kaolinite clay

Study of the scavenging behavior and structural changes accompanying the interaction of aqueous Pb2+ and Sr2+ ions with calcite

Contact Info

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Resources

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Characterization of Sr²⁺uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

Characterization of Sr²⁺uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT