Electrochemical studies of technetium at a mercury electrode

Grassi, Joaquín; Devynck, Jacques; Trémillon, B.

doi:10.1016/s0003-2670(01)93194-0

Cited by 28 publications

(13 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Considerable increase of the limiting current of the second wave with growth of HN0 3 concentration in the solution (Fig. 2 A, 2B] does not permit to account the observed reduction process for Tc amalgamation, since the latter process has been reported to occur at more negative potentials (£ 1/2 , = -0.8 to -0.9 V/SCE) [1,3] its limiting current being independent on solution acidity. Analysis of CV data, obtained for the catalytic reduction process under study (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The latter compound interacts with Tc(III) resulting in formation of gaseous nitrogen oxides (3,4) and Tc(IV) adsorbed on HMDE surface. Regeneration of HN0 2 may take place according to reaction (5).…”

Section: Methodsmentioning

confidence: 99%

“…Electrochemical behavior of technetium(VII) ions in nitrate solutions [1,2] is much less studied if compare with the solutions of other mineral acids (HCl, H 2 S0 4 , HCIO4) [3][4][5][6][7], since electrochemical reduction of Tc0 4 ions at the electrode is complicated by the possible redox reaction of formed Tc species in the oxidation states (+3, +4) with nitrate ions and the products of their electrochemical reduction (N0 2 , NO, N 2 0 etc.) [2,8].…”

Section: Introductionmentioning

confidence: 99%

“…Such data on the mechanism of Tc reduction in nitric acid media seem to be of undoubtfull importance for the development of the Tc electrodeposition process applicable for the utilization in PUREX waste treatment. 3 and KOH (analytical grade) and bidistilled water. Triply distilled mercury (Merck) has been used for the electrode preparation.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Technetium Electrochemical Reduction in Nitric Solutions at Mercury and Carbon Electrodes

et al. 1997

View full text Add to dashboard Cite

Nitric acid / Electrochemical destruction / Technetium electrodeposition SummaryPolarographic and cyclic voltammetry (CV) measurements in nitric solutions of Tc(VII) (HNO, + ΚΝ0 3 ; μ = 1.0, pH = 0.0-6.0) at hanging mercury drop electrode (HMDE) indicate two reduction processes occurring at pH dependent E in = 0.069 to -0.205 V/SCE and pH independent E, a = -0.71 V/SCE correspondingly. The first process is referred to Tc(VII)/Tc(III) diffusion controlled reduction. Observed high absolute values and dependence of the limiting current both on Tc(VII] and NOj concentration in the solution allow to account the second reduction process for NOi ions destruction, catalyzed by Tc(IV, III) ions. Electrochemical destruction of N0 3 ions in solutions 2.0-4.0 Μ HNO, containing (0.2-2.0)10" 3 Μ Tc(VII) has been examined, using potentiostatic electrolysis with graphite cathode. In 4 Μ HN0 3 electrolysis at the potentials Ε = -0.6 to -1.0 V has been found to result in partial (5-35%) Tc electrodeposition, accompanied by acceleration of electrochemical denitration process. Mechanism of N0 3~ ions electrochemical destruction, including catalysis by the Tc(IV, III) hydrated oxides deposited at the electrode surface is discussed.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Technetium Electrochemical Reduction in Nitric Solutions at Mercury and Carbon Electrodes

et al. 1997

View full text Add to dashboard Cite

show abstract

“…Although several oxidation states of Tc are reported in the literature (ranging from +II to +VII) [6][7][8][9], Tc(VII) and Tc(IV) are the prevailing long-term stable redox states in the absence of any complexing ligand other than water under non reducing and reducing conditions, respectively. Heptavalent Tc exists as highly soluble and mobile pertechnetate anion (TcO 4 − ), whereas Tc(IV) forms sparingly soluble hydrous oxides (TcO 2 ⋅ xH 2 O(s)).…”

Section: Introductionmentioning

confidence: 99%

Redox chemistry of Tc(VII)/Tc(IV) in dilute to concentrated NaCl and MgCl₂ solutions

Yalçıntaş

Gaona²,

Scheinost

et al. 2014

Radiochimica Acta

View full text Add to dashboard Cite

Redox speciation of Tc in the aqueous phase was further confirmed by solvent extraction. A good agreement is obtained between the experimentally determined Tc redox distribution and thermodynamic calculations based on NEA-TDB (Nuclear Energy Agency, Thermochemical Database) and ionic strength corrections by SIT or Pitzer approaches. These observations indicate that experimental pH c and h values in buffered systems can be considered as reliable parameters to predict the redox behaviour of Tc in dilute to highly concentrated NaCl and MgCl 2 solutions. h of the system and aqueous concentration of Tc(IV) in equilibrium with TcO 2 ⋅ 1.6H 2 O(s) are strongly affected by elevated ionic strength, especially in the case of 4.5 M MgCl 2 solutions. In such concentrated brines and under alkaline conditions (pH c = pH max ∼ 9), kinetics play a relevant role and thermodynamic equilibrium for the system Tc(IV)(aq) ⇔ Tc(IV)(s) was not attained from oversaturation conditions within the timeframe of this study (395 days). Tc(VII) is reduced to Tc(IV) by magnetite, mackinawite and siderite suspensions at pH c = 8-9 in concentrated NaCl and MgCl 2 solutions. Sorption is very high in

show abstract

Some fundamentals of technetium chemistry

Schwochau

2000

Technetium

View full text Add to dashboard Cite

Electrochemical studies of technetium at a mercury electrode

Cited by 28 publications

References 16 publications

Technetium Electrochemical Reduction in Nitric Solutions at Mercury and Carbon Electrodes

Technetium Electrochemical Reduction in Nitric Solutions at Mercury and Carbon Electrodes

Redox chemistry of Tc(VII)/Tc(IV) in dilute to concentrated NaCl and MgCl₂ solutions

Some fundamentals of technetium chemistry

Contact Info

Product

Resources

About

Electrochemical studies of technetium at a mercury electrode

Cited by 28 publications

References 16 publications

Technetium Electrochemical Reduction in Nitric Solutions at Mercury and Carbon Electrodes

Technetium Electrochemical Reduction in Nitric Solutions at Mercury and Carbon Electrodes

Redox chemistry of Tc(VII)/Tc(IV) in dilute to concentrated NaCl and MgCl2 solutions

Some fundamentals of technetium chemistry

Contact Info

Product

Resources

About

Redox chemistry of Tc(VII)/Tc(IV) in dilute to concentrated NaCl and MgCl₂ solutions