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Caire, Jean-Pierre; Laurent, Flore; Cullie, S.; Dalard, F.; Fulconis, J.M.; Delagrange, H.

doi:10.1023/a:1025051306270

Cited by 15 publications

(7 citation statements)

References 2 publications

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“…Initially, ethanol was oxidized by ozone to produce acetaldehyde and acetic acid 24 (eqn 1 and 2). The production of acetic acid facilitated ozone to oxidize Ce +3 to Ce +4 , 25,26 (eqn 3). The excess acetate acted as a base to catalyze the conversion of acetaldehyde with ethanol to form the hemiacetal, 1-ethoxyethan-1-ol (eqn 4), which then formed complexes with the available cerium ions (eqn 5) (eqn 6).…”

Section: Resultsmentioning

confidence: 99%

Mechanistic insights into the acetate-accelerated synthesis of crystalline ceria nanoparticles

et al. 2020

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Section: Resultsmentioning

confidence: 99%

Mechanistic insights into the acetate-accelerated synthesis of crystalline ceria nanoparticles

et al. 2020

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“…Ce(III), so generated is then oxidized back to Ce(IV) by reaction with ozone ( E 0 = 2.07 V versus NHE), so as to maintain the required Ce(IV) concentration, hence the sustained corrosion rates and a lower treatment time. This oxidation of reduced cerium occurs as per the following chemical reaction Therein, dissolved ozone also undergoes a self-decomposition reaction to molecular oxygen.…”

Section: Introductionmentioning

confidence: 99%

“…The equipment was successfully decontaminated up to the desired release levels of radioactivity. Carie et al , pioneered the decontamination process for AISI 304 L steel by Ce(IV) in 4 M nitric acid (instead of sulfuric acid), in which the reduced cerium was also reoxidized by ozone. In the first part of their work, the authors reported a decontamination study targeted at obtaining a corrosion rate of ≈10 μm per day.…”

Section: Introductionmentioning

confidence: 99%

Oxidation of Ce(III) to Ce(IV) by Ozone in Nitric Acid Medium Using a Static Mixer: Mathematical Modeling and Experimental Validation

Singh

Vincent

Bhaskarwar

et al. 2017

Ind. Eng. Chem. Res.

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This paper deals with a cerium based redox chemical process which is employed to remove fixed radioactive contaminants from alpha bearing metallic surfaces, worldwide. Oxidation of cerium to its fourth valence state is a crucial step of this process. We present an inactive bench scale study to obtain the effect of various process parameters on conversion of Ce(III) to Ce(IV) by ozone in nitric acid medium, using an SMX type of static mixer. Two different mathematical models, one considering a simple semibatch mixed reactor configuration and another based on the concept of axial dispersion, were developed for predicting Ce(III) conversions using the said static mixer, in a full recycle mode. Simulation results from the models matched fairly well to experimental data, with respective mean absolute percentage deviations of 21.1% and 17.4%, computed over all the parameters. An attempt to extend these models for other non-nuclear environmental applications is also described.

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“…Common chemical techniques are mostly redox chemistry based and involve either simple one step treatments such as the cerium oxidant based MEDOC process (Metal Decontamination by Oxidation with Cerium) [5][6][7][8][9][10] or more complex multistep processes such as the permanganate oxidant based CORD process (Chemical Oxidising Reduction Decontamination) [11][12][13][14][15]. Importantly, in combination with actinide/transition metal complexants such as hydroxycarboxylic acids [2] or carbonates in the COL process (Carbonate-based Oxidative Leaching) [16][17][18][19], application of hydrogen peroxide has proved to be a useful single step process for spent uranium dioxide fuel pellet dissolution.…”

Section: Introductionmentioning

confidence: 99%

The effect of hydrogen peroxide on uranium oxide films on 316L stainless steel

Wilbraham

Boxall

Goddard

et al. 2015

Journal of Nuclear Materials

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h i g h l i g h t sThe first report of the presence of both UO 2 and polymeric UO 2 2+ in the same electrodeposited U oxide sample.The action of H 2 O 2 on electrodeposited U oxides is described using corrosion based concepts.Electrodeposited U oxide freely dissolves at hydrogen peroxide concentrations <100 lmol dm À3 .At [H 2 O 2 ] > 0.1 mmol dm À3 dissolution is inhibited by formation of a studtite passivation layer. At [H 2 O 2 ] P 1 mol dm À3 studtite formation competes with uranyl-peroxide complex formation. a b s t r a c tFor the first time the effect of hydrogen peroxide on the dissolution of electrodeposited uranium oxide films on 316L stainless steel planchets (acting as simulant uranium-contaminated metal surfaces) has been studied. Analysis of the H 2 O 2 -mediated film dissolution processes via open circuit potentiometry, alpha counting and SEM/EDX imaging has shown that in near-neutral solutions of pH 6.1 and at [H 2 O 2 ] 6 100 lmol dm À3 the electrodeposited uranium oxide layer is freely dissolving, the associated rate of film dissolution being significantly increased over leaching of similar films in pH 6.1 peroxide-free water. At H 2 O 2 concentrations between 1 mmol dm À3 and 0.1 mol dm À3 , formation of an insoluble studtite product layer occurs at the surface of the uranium oxide film. In analogy to corrosion processes on common metal substrates such as steel, the studtite layer effectively passivates the underlying uranium oxide layer against subsequent dissolution. Finally, at [H 2 O 2 ] > 0.1 mol dm À3 the uranium oxide film, again in analogy to common corrosion processes, behaves as if in a transpassive state and begins to dissolve. This transition from passive to transpassive behaviour in the effect of peroxide concentration on UO 2 films has not hitherto been observed or explored, either in terms of corrosion processes or otherwise. Through consideration of thermodynamic solubility product and complex formation constant data, we attribute the transition to the formation of soluble uranyl-peroxide complexes under mildly alkaline, high [H 2 O 2 ] conditions -a conclusion that has implications for the design of both acid minimal, metal ion oxidant-free decontamination strategies with low secondary waste arisings, and single step processes for spent nuclear fuel dissolution such as the Carbonate-based Oxidative Leaching (COL) process.

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Cited by 15 publications

References 2 publications

Mechanistic insights into the acetate-accelerated synthesis of crystalline ceria nanoparticles

Mechanistic insights into the acetate-accelerated synthesis of crystalline ceria nanoparticles

Oxidation of Ce(III) to Ce(IV) by Ozone in Nitric Acid Medium Using a Static Mixer: Mathematical Modeling and Experimental Validation

The effect of hydrogen peroxide on uranium oxide films on 316L stainless steel

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