Electrometric studies on uranyl molybdates as a function of pH

Prasad, Shiva; Barros, Jaqueline Viana

doi:10.1590/s0100-46701998000100005

Cited by 3 publications

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“…The model predicts that the reactor solution would become saturated with respect to uranyl oxide hydrate at a pH around 3; however, there is uncertainty as to the solubility product (K sp ) of uranyl molybdate. Sparse experimental data (e.g., Prasad and Barros 1998;Ferris 1961) suggest the log 10 K sp for uranyl molybdate falls in the range of -13 to -15 (for the basis reaction: UO 2 MoO 4 (s) ↔ UO 2 2+ + MoO 4…”

Section: Saturation State and Molybdenum Speciationmentioning

confidence: 99%

Report Documenting the Speciation of Metals in Homogeneous Reactor Solutions : RERTR Milestone Report

Jerden¹,

Fortner²,

Stepinski³

2014

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Section: Saturation State and Molybdenum Speciationmentioning

confidence: 99%

Report Documenting the Speciation of Metals in Homogeneous Reactor Solutions : RERTR Milestone Report

Jerden¹,

Fortner²,

Stepinski³

2014

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“…Some decrease in U(VI) removal in the presence of added molybdate might also be attributed to the formation of uranyl molybdate complexes. These species have limited solubility and hence could potentially reduce the bioavailability of U(VI) for microbial reduction (Prasad and Barros, 1998;Kiran and Apblett, 2004). …”

Section: Figure 4 Time Course Of U(vi) Reduction By Fbr Biomass Inmentioning

confidence: 99%

Uranium (VI) Reduction by Denitrifying Biomass

Gentile

et al. 2005

Bioremediation Journal

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Groundwater near the S3 ponds at the US Department of Energy's Y-12 site in Oak Ridge, Tennessee, is contaminated by high levels of nitrate (up to 160 mM) and U(VI) (∼0.3 mM). To minimize nitrate inhibition, the authors proposed extraction of contaminated groundwater, nitrate removal in a denitrifying fluidized bed bioreactor (FBR), and return of nitrate-free effluent to the aquifer to stimulate in situ microbial reduction of U(VI). In the presence of carbonate, U(VI) sorption to biomass was negligible, but in its absence, sorption was significant. Biomass reduced U(VI) to U(IV), exhibiting slow firstorder removal with respect to U(VI). Addition of electron donor increased rates. Addition of an inhibitor of sulfate reduction (molybdate) slowed the rate and inhibited sulfate reduction. Denitrifying β-Proteobacteria dominated clone libraries of SSU rRNA and dsrA gene sequences. Approximately 10% were low-G+C microorganisms that had 90% to 92% sequence identity with Sporomusa, Acetonema, and Propionispora. The dsrA sequences were dominated by a single clone with ∼80% nucleotide identity to dsrA of Desulfovibrio vulgaris sub sp. oxamicus. The authors conclude that some members of this denitrifyng community reduce uranium, and that sulfate-reducing bacteria likely contribute to this capability.

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Electrometric investigations on the formation of cerium(III) tungstates as a function of PH

et al. 2000

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The course of reaction between cerium(III) nitrate and different sodium tungstates (Na2WO4, Na10W12O41 and Na6W12O39) has been followed by means of pH and conductometric titrations between the reactants at different pH levels, in aqueous and alcoholic media, with each of the reagents alternatively used as titrant. The electrometric experiments provide definite evidence of the formation of normal-Ce2O3.3WO3 and para- 5Ce2O3.36WO3 tungstates of cerium in the vicinity of pH 6.2 and 5.3. The formation of normal tungstate is almost quantitative and the pH titrations offer a simple means for determination of cerium(III) or tungstate solutions at suitable concentrations and pH range.

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Electrometric studies on uranyl molybdates as a function of pH

Cited by 3 publications

References 0 publications

Report Documenting the Speciation of Metals in Homogeneous Reactor Solutions : RERTR Milestone Report

Report Documenting the Speciation of Metals in Homogeneous Reactor Solutions : RERTR Milestone Report

Uranium (VI) Reduction by Denitrifying Biomass

Electrometric investigations on the formation of cerium(III) tungstates as a function of PH

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