Fundamental Data Acquisition toward Silver-Silver Chloride Reference Electrode

Yoon, Dalsung; Baggett, Adam; Phongikaroon, Supathorn; King, J. A.; Marsden, K. C.

doi:10.1149/2.0721906jes

Cited by 24 publications

(14 citation statements)

References 20 publications

(45 reference statements)

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“…38 The scan starts from the positive potential to the negative potential and returns to the original potential. The observed redox peaks of Cr (II), Fe(II), Co(II), and Ni(II) in LiCl-KCl were consistent with the previous measurements obtained by Park et Yang and Hudson 29 Yoon et al 30 Shirai et al 31 Barin et al Figure 3 shows the formal potentials of the four reactions. The results of numerical fitting and correlations were compared with previously reported values (see Table SI (available online at stacks.…”

Section: Resultssupporting

confidence: 89%

Spectroelectrochemical Behavior of Cr, Fe, Co, and Ni in LiCl-KCl Molten Salt for Decontaminating Radioactive Metallic Wastes

Yoon

Choi

2021

J. Electrochem. Soc.

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This study examines the thermodynamic, kinetic, and spectroscopic behaviors of Cr, Fe, Co, and Ni to lay the foundation to develop an electrochemical decontamination process for radioactive metallic wastes. Cyclic voltammetry combined with numerical fitting was used to obtain the formal potentials, standard rate constants, and diffusion coefficients of redox reactions, Cr(II)/Cr, Fe(II)/Fe(0), Co(II)/Co(0), and Ni(II)/Ni(0), in LiCl-KCl at 773 K. The order of the diffusion coefficients was 10–5 cm2 s−1, which agrees with the existing data and the standard rate constants showed similar values with the order of 10–3 cm s−1 between experimental correlations and numerical fitting. UV–vis-NIR absorption spectroscopy of the metallic constituents was performed to derive molar absorption coefficients and molecular structures in molten salt media. In particular, the redox reaction of Cr(III)/Cr(II) was investigated by chronoabsorptometry to obtain its formal potential, the number of electrons, and the diffusion coefficient of Cr(II). The obtained reaction properties were used in the numerical modeling of the ECE reaction in a Ni and Co binary system to reproduce the experimental results of CV, revealing the presence of chemical reaction. The findings of this study will be directly used for designing a decontamination process to produce acceptable waste forms and reduce waste volume.

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Section: Resultssupporting

confidence: 89%

Spectroelectrochemical Behavior of Cr, Fe, Co, and Ni in LiCl-KCl Molten Salt for Decontaminating Radioactive Metallic Wastes

Yoon

Choi

2021

J. Electrochem. Soc.

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“…9 To calculate the formal potential and activity coefficient of GdCl 3 , its Gibbs free energy of formation must be known, and it is needed to convert the Gd metal electrode potential vs the Ag/AgCl RE to a potential vs the Cl 2 /Cl − RE. For convenience, the potential difference of Ag/AgCl RE with respect to a Cl 2 /Cl − electrode from a recent study by Yoon et al 15 was used here. At 773 K, the Ag/AgCl electrode vs Cl 2 /Cl − RE is -1.21 V.…”

Section: Resultsmentioning

confidence: 99%

Study of Potentiometry for Monitoring Activity of GdCl₃ in Molten LiCl-KCl Salt

Cao¹,

Herrmann²,

Fredrickson³

et al. 2022

ECS Adv.

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In pyroprocessing spent nuclear fuels by electrorefining in molten LiCl-KCl salt, it is desired to monitor in real time the UCl3 concentration in the salt for safeguards purposes. Current chemical analysis of the highly radioactive salt for electrorefining by an inductively coupled plasma technique is inconvenient and usually time-consuming in generating the salt composition results. In this paper, we evaluated whether a simple potentiometry approach can be used for real-time monitoring of GdCl3, a surrogate for UCl3, in LiCl-KCl salt by measuring the open circuit potential of a Gd metal electrode with respect to Ag/AgCl reference electrode (RE) when GdCl3 salt is incrementally added to the LiCl-KCl salt. Additions of LaCl3, CeCl3 and NdCl3 salts were used for evaluating the effects of other chloride salts on the selectivity of the Gd metal electrode versus Ag/AgCl RE. The apparent Gibbs free energy and activity coefficient of GdCl3 in the LiCl-KCl-GdCl3 salt system were also calculated and compared with data in literature. During the study of GdCl3 activity measurement using potentiometry, we unexpectedly noticed that, over time, Gd metal is structurally unstable and can be dissolved in LiCl-KCl salt when GdCl3 is present.

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“…Since Yang and Hudson's equation was obtained from experiments where the lowest mole fraction of AgCl was 0.0146, the equation needed to be extrapolated for this study, which used 1 wt% of AgCl (0.0039 mole fraction). Recently, a new experimental equation was suggested by Yoon et al 37 They conducted experiments where the minimum mole fraction was 0.00039 (0.1 wt% of AgCl). To validate the standard apparent reduction potentials obtained in this study, both equations were applied and the results were compared.…”

Section: Resultsmentioning

confidence: 99%

Experimental Studies of Lanthanides Electro-Codeposition in Molten Salt to Evaluate a 1-D Electrorefining Computer Model

Jung¹,

Yim²

2020

J. Electrochem. Soc.

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Codeposition of elements is an important phenomenon in the analysis and understanding of mass transfer in electrorefining of pyroprocessing. This study investigated the codeposition of lanthanides in molten salt. Mass transport experiments were conducted to examine the accuracy of the 1D electrorefining model, ERAD. Three lanthanides (La, Ce, and Gd) were selected because their standard reduction potentials are close to each other which facilitates codeposition. For the electrodeposition experiments, six electrochemical cells were used with varying ratios of lanthanides and the electrode potential ranging from 0.00 V to 0.15 V. This controlled the codeposition environment. The resulting electrodeposits were analyzed by ICP-OES and compared with the simulation results from ERAD. The ERAD input parameters were determined through electrochemical studies. Theoretical codeposition ratios were also analyzed using polarization curves. The study indicated that the current density of each element played a major role in its codeposition, as did thermodynamically determined reduction potentials. The overall results were comprehensively investigated and showed that ERAD can reasonably show the tendency of the codeposition results obtained from the experiments. With minor revision, it is expected that this 1D computer code could be effectively utilized for modeling the mass transport of the electrorefining process of pyroprocessing.

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Fundamental Data Acquisition toward Silver-Silver Chloride Reference Electrode

Cited by 24 publications

References 20 publications

Spectroelectrochemical Behavior of Cr, Fe, Co, and Ni in LiCl-KCl Molten Salt for Decontaminating Radioactive Metallic Wastes

Spectroelectrochemical Behavior of Cr, Fe, Co, and Ni in LiCl-KCl Molten Salt for Decontaminating Radioactive Metallic Wastes

Study of Potentiometry for Monitoring Activity of GdCl₃ in Molten LiCl-KCl Salt

Experimental Studies of Lanthanides Electro-Codeposition in Molten Salt to Evaluate a 1-D Electrorefining Computer Model

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Fundamental Data Acquisition toward Silver-Silver Chloride Reference Electrode

Cited by 24 publications

References 20 publications

Spectroelectrochemical Behavior of Cr, Fe, Co, and Ni in LiCl-KCl Molten Salt for Decontaminating Radioactive Metallic Wastes

Spectroelectrochemical Behavior of Cr, Fe, Co, and Ni in LiCl-KCl Molten Salt for Decontaminating Radioactive Metallic Wastes

Study of Potentiometry for Monitoring Activity of GdCl3 in Molten LiCl-KCl Salt

Experimental Studies of Lanthanides Electro-Codeposition in Molten Salt to Evaluate a 1-D Electrorefining Computer Model

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Study of Potentiometry for Monitoring Activity of GdCl₃ in Molten LiCl-KCl Salt