Study of the reduction mechanism and the adsorption properties of uranium (VI)-cupferron complexes using various electrochemical techniques

Paneli, M.; Ouguenoune, H.; David, F.; Bolyos, A.

doi:10.1016/0003-2670(94)00632-v

Cited by 21 publications

(15 citation statements)

References 15 publications

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“…In order to maintain a constant pH of the electrolyte and, since we have also to consider the structure with time of the double layer at the electrode, we have chosen acetic buffer solutions, which was studied in a previous work [12].…”

Section: Methodsmentioning

confidence: 99%

“…However, as we will see, the time parameter playing an important role in the chemical and electrochemical reactions, we will also use new techniques which have been recently realised at the laboratory and programmed with LabView software. This is 3D Polarography [11] and 3D interracial differential capacity measurements [12] where intensity or capacity is measured as a function of potential and time.…”

Section: Methodsmentioning

confidence: 99%

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Electrochemical behaviour of technetium in acetic buffer

et al. 1999

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In order to understand the complex reduction mechanism of pertechnetate ions on mercury electrode we have developed electrochemical techniques which use an additional time parameter to the classical methods applied on mercury microelectrode: 3 Dimensional polarography and 3D differential capacity measurements have been investigated in addition with coulometry, cyclic voltammetry, and radioactivity determinations. We have concluded that the first VII -> III reduction wave, which has been described in literature, has to be associated with the successive VII -> V reactions followed by the disproportionation of Tc(V) and formation of Tc(VI) and insoluble tetravalent species which are adsorbed on the electrode and reduced to trivalent ions. Then, reduction of Tc(III) to Tc(0) is reached through Tc(II) and Tc(I) intermediate species. The intermediates are characterised depending on the time window of observation.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Electrochemical behaviour of technetium in acetic buffer

et al. 1999

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“…U(V) and U(V) ! U(III) [26] with the former peak appearing at more positive potentials. A recent study describing an AdSV scheme for the determination of uranium on a BiFE in the presence of cupferron indicated that in acetate buffer (pH 4.5) the U(VI) !…”

Section: Introductionmentioning

confidence: 96%

Adsorptive Stripping Voltammetric Determination of Trace Uranium with a Bismuth‐Film Electrode Based on the U(VI)→U(V) Reduction Step of the Uranium‐Cupferron Complex

2006

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This work reports the use of adsorptive stripping voltammetry (AdSV) for the determination of uranium on a preplated rotating-disk bismuth-film electrode (BiFE). The principle of the method relied on the complexation of U(VI) ions with cupferron and the subsequent adsorptive accumulation of the complex on the surface of the BiFE. The uranium in the accumulated complex was then reduced by means of a cathodic voltammetric scan while the analytically useful U(VI) ! U(V) reduction signal was monitored. The experimental variables as well as potential interferences were investigated and the figures of merit of the method were established. Using the selected conditions, the 3s limit of detection for uranium was 0.1 mg L À1 at a preconcentration time of 480 s and the relative standard deviation was 4.7% at the 5 mg L À1 level for a preconcentration time of 120 s (n ¼ 8). The accuracy of the method was established by analyzing a reference sea water sample.

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“…In the detection step, the anodic stripping was performed in the same acidic solution by scanning the potential from À 0.80 V to 0.40 V. The detection of 500 ppb (mg/L) U(VI) in 0.05 M CH 3 COONa at pH 5 using an unmodified carbon paste electrode did not yield any voltammetric response (current) for uranium, indicating that the conductive matrix was inert with respect to uranium adsorption. For the Ac-Phos SAMMS modified carbon paste electrode, the anodic peak of uranium appeared at À 0.37 V, which is likely associated with the oxidation of U(V) to U(VI) [20]. A series of experiments at different aqueous U(VI) concentrations showed that the current of this À 0.37 V peak was proportional to the U(VI) concentration.…”

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confidence: 96%

Carbon Paste Electrode Modified with Carbamoylphosphonic Acid Functionalized Mesoporous Silica: A New Mercury‐Free Sensor for Uranium Detection

et al. 2004

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This study reports a new approach for developing a uranium electrochemical sensor that is mercury-free, solid-state, and has less chance for ligand depletion than existing sensors. A carbon-paste electrode modified with carbamoylphosphonic acid self-assembled monolayer on mesoporous silica was developed for uranium detection based on an adsorptive square-wave stripping votammetry technique. Voltammetric responses for uranium detection are reported as a function of pH, preconcentration time, and aqueous phase uranium concentration. The uranium detection limit is 25 ppb after 5 minutes preconcentration and improved to 1 ppb after 20 minutes preconcentration. The relative standard deviations are normally less than 5%.

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Study of the reduction mechanism and the adsorption properties of uranium (VI)-cupferron complexes using various electrochemical techniques

Cited by 21 publications

References 15 publications

Electrochemical behaviour of technetium in acetic buffer

Electrochemical behaviour of technetium in acetic buffer

Adsorptive Stripping Voltammetric Determination of Trace Uranium with a Bismuth‐Film Electrode Based on the U(VI)→U(V) Reduction Step of the Uranium‐Cupferron Complex

Carbon Paste Electrode Modified with Carbamoylphosphonic Acid Functionalized Mesoporous Silica: A New Mercury‐Free Sensor for Uranium Detection

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