Generation of uranyl/carbonate/hydroxide “coatings’' at the vaterite surface

Boughriet, A.; Gengembre, L.; Laureyns, J.; Récourt, Philippe; Langelin, H. R.; Nacer, A.

doi:10.1039/a909223d

Cited by 18 publications

(13 citation statements)

References 9 publications

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“…The tabular CaCO 3 particles show only two weak over-lapped bands at 1084 and 1092 cm -1 because of the low crystallinity of the particles. The spectral profile at 1084 and 1092 cm -1 is the characteristics of vaterite structure (Behrens et al, 1995;Boughriet et al, 2000;Lee et al, 2001), which verifies the crystal structure of the tabular CaCO 3 particles determined by SEM and XRD analyses.…”

Section: Resultssupporting

confidence: 70%

Synthesis of Calcium Carbonate Particles in Octylamine/Water Bilayer Systems

Wang

White

Adair

2014

KONA

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Calcium carbonate particles with various shapes and morphologies were prepared via precipitation in an octylamine/water self-assembly bilayer systems. Crystal structure and shape of the CaCO 3 particles were determined by the water to octylamine molar ratio R of the bilayer. At R = 16.0, phase pure calcite particles with a "hopper crystal" morphology were formed, the average particle size of the hopper crystal is 10 μm with welldefined edges on the hopper faces. Decrease the R ratio to 7.2 eventually leads to the formation of 3 μm tabular CaCO 3 particles which are predominated by vaterite structure. For an intermediate R of 10.8, spherical vaterite aggregates and rhombohedral calcite particles were produced. Thermal decomposition of the CaCO 3 particles was observed at around 710°C. The mechanism of particle evolution in the self-assembly bilayer, particularly the formation of "hopper crystal" calcite was discussed.

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Section: Resultssupporting

confidence: 70%

Synthesis of Calcium Carbonate Particles in Octylamine/Water Bilayer Systems

Wang

White

Adair

2014

KONA

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“…For CaCO 3 ,t he C1s peak at 289.3 eV represented the carbonate carbon in CaCO 3 while the C1sp eak at 284.9 eV could be assignedt oc arbon contamination. [17] To the best of our knowledge,t he C1sX PS spectrum for calcium acetate has not been reported in the literature. Therefore, the assignment of the C1sp eaks for calcium acetate was based on literature reporting the C1sX PS spectra of different carbon functional groups.…”

Section: Insights Into Acid Removal With Cacomentioning

confidence: 95%

Tailoring the Composition of Bio‐oil by Vapor‐Phase Removal of Organic Acids

2015

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Selective removal of organic acids from biomass pyrolysis vapors was demonstrated. A broad adsorbent range was tested with CaCO3 showing the best selectivity. Extensive material characterization demonstrated that the acid removal occurred through monolayer adsorption on CaCO3. Adsorbent regeneration was achieved by in situ heat treatment of the postreaction adsorbent where the adsorbed acid was converted into a ketone. The mitigation of the loss of other products was achieved by using surface modified CaCO3 materials, resulting in a significant improvement in the selectivity toward organic acid removal. The surface modification appeared to lead to formation of a metal-carboxylate intermediate consisting of both acetate and carbonate groups. Acetate group on the CaCO3 surface resulted in the suppression of side reactions. Generally, a higher acid removal was accompanied with a greater loss of other compounds, which could be tuned by using CaCO3 with different surface modification.

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“…The equilibrium constant K 103 for reaction (9) was then calculated for every temperature according to equation (10). Furthermore an estimated value for the formation Gibbs free energy is given, based on equation (11) and the values Δ f G°(UO 2 2+ ) = -989.5 kJ /mol and Δ f G°(CO 3 2 ) = -528.0 kJ/mol (Boughriet et al 2000 (9.174 ± 0.039)·10 -3 (9.210 ± 0.042)·10 -3 (9.239 ± 0.045)·10 -3 (9.269 ± 0.051)·10 -3 (9.285 ± 0.045)·10 -3 (9.295 ± 0.042)·10 -3 (9.308 ± 0.045)·10 -3 (9.331 ± 0.045)·10 -3 (9.354 ± 0.048)·10 -3 (9.374 ± 0.048)·10 -3 (9.390 ± 0.042)·10 -3 (9.410 ± 0.048)·10 -3 (9.433 ± 0.048)·10 -3 (9.466 ± 0.048)·10 -3 Fig.4. Table 1 shows the determined complex concentrations and the Gibbs free energies.…”

Section: Resultsmentioning

confidence: 99%

Uranium, Mining and Hydrogeology

Merkel

Hasche-Berger²

2008

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Generation of uranyl/carbonate/hydroxide “coatings’' at the vaterite surface

Cited by 18 publications

References 9 publications

Synthesis of Calcium Carbonate Particles in Octylamine/Water Bilayer Systems

Synthesis of Calcium Carbonate Particles in Octylamine/Water Bilayer Systems

Tailoring the Composition of Bio‐oil by Vapor‐Phase Removal of Organic Acids

Uranium, Mining and Hydrogeology

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