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Iodide
The Experts below are selected from a list of 198 Experts worldwide ranked by ideXlab platform
James Degruson – One of the best experts on this subject based on the ideXlab platform.
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Effect of sodium Iodide additive on the electrochemical performance of sodium/nickel chloride cells
Journal of Applied Electrochemistry, 2000Co-Authors: Jai Prakash, L. Redey, Donald R. Vissers, James DegrusonAbstract:The effect of sodium Iodide and sulfur additives on the performance of Na/β′′-alumina/NaAlCl_4/NiCl_2/Ni cells was investigated in quasi-sealed laboratory research cells (0.5–1.0 Ah capacity) and in sealed full-size cells (4 Ah capacity). It was found that sodium Iodide additive especially in combination with sulfur in Na/NiCl_2 cells significantly increases the usable capacity and reduces the impedance of the Na/NiCl_2 cells. It is proposed that the use of sodium Iodide enhances the energy and power performance of the NiCl_2 electrode by two different mechanisms. The first mechanism, Iodide ion doping of the anodically formed solid NiCl_2, is dominant at potentials lower than that of iodine evolution. The doping effect of the Iodide ions produces a higher-capacity, lower-impedance NiCl_2 layer on the positive elecelectrode. The second mechanism, anodic formation of very reactive iodine species, is effective when the cell is cycled through the iodine evolution potential range (2.8–3.1 V vs Na). During this process, the dissolved iodine species improve electrode kinetics through liquid-phase mass transport. Use of the sodium Iodide additive is safe in sealed cells, causing no over-pressurizing problems. A maximum pressure increase of only 10 kPa was detected by a pressure sensor during severe overcharge tests.
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effect of sodium Iodide additive on the electrochemical performance of sodium nickel chloride cells
Journal of Applied Electrochemistry, 2000Co-Authors: Jai Prakash, L. Redey, Donald R. Vissers, James DegrusonAbstract:The effect of sodium Iodide and sulfur additives on the performance of Na/β′′-alumina/NaAlCl4/NiCl2/Ni cells was investigated in quasi-sealed laboratory research cells (0.5–1.0 Ah capacity) and in sealed full-size cells (4 Ah capacity). It was found that sodium Iodide additive especially in combination with sulfur in Na/NiCl2 cells significantly increases the usable capacity and reduces the impedance of the Na/NiCl2 cells. It is proposed that the use of sodium Iodide enhances the energy and power performance of the NiCl2 electrode by two different mechanisms. The first mechanism, Iodide ion doping of the anodically formed solid NiCl2, is dominant at potentials lower than that of iodine evolution. The doping effect of the Iodide ions produces a higher-capacity, lower-impedance NiCl2 layer on the positive elecelectrode. The second mechanism, anodic formation of very reactive iodine species, is effective when the cell is cycled through the iodine evolution potential range (2.8–3.1 V vs Na). During this process, the dissolved iodine species improve electrode kinetics through liquid-phase mass transport. Use of the sodium Iodide additive is safe in sealed cells, causing no over-pressurizing problems. A maximum pressure increase of only 10 kPa was detected by a pressure sensor during severe overcharge tests.
Jai Prakash – One of the best experts on this subject based on the ideXlab platform.
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Effect of sodium Iodide additive on the electrochemical performance of sodium/nickel chloride cells
Journal of Applied Electrochemistry, 2000Co-Authors: Jai Prakash, L. Redey, Donald R. Vissers, James DegrusonAbstract:The effect of sodium Iodide and sulfur additives on the performance of Na/β′′-alumina/NaAlCl_4/NiCl_2/Ni cells was investigated in quasi-sealed laboratory research cells (0.5–1.0 Ah capacity) and in sealed full-size cells (4 Ah capacity). It was found that sodium Iodide additive especially in combination with sulfur in Na/NiCl_2 cells significantly increases the usable capacity and reduces the impedance of the Na/NiCl_2 cells. It is proposed that the use of sodium Iodide enhances the energy and power performance of the NiCl_2 electrode by two different mechanisms. The first mechanism, Iodide ion doping of the anodically formed solid NiCl_2, is dominant at potentials lower than that of iodine evolution. The doping effect of the Iodide ions produces a higher-capacity, lower-impedance NiCl_2 layer on the positive electrode. The second mechanism, anodic formation of very reactive iodine species, is effective when the cell is cycled through the iodine evolution potential range (2.8–3.1 V vs Na). During this process, the dissolved iodine species improve electrode kinetics through liquid-phase mass transport. Use of the sodium Iodide additive is safe in sealed cells, causing no over-pressurizing problems. A maximum pressure increase of only 10 kPa was detected by a pressure sensor during severe overcharge tests.
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effect of sodium Iodide additive on the electrochemical performance of sodium nickel chloride cells
Journal of Applied Electrochemistry, 2000Co-Authors: Jai Prakash, L. Redey, Donald R. Vissers, James DegrusonAbstract:The effect of sodium Iodide and sulfur additives on the performance of Na/β′′-alumina/NaAlCl4/NiCl2/Ni cells was investigated in quasi-sealed laboratory research cells (0.5–1.0 Ah capacity) and in sealed full-size cells (4 Ah capacity). It was found that sodium Iodide additive especially in combination with sulfur in Na/NiCl2 cells significantly increases the usable capacity and reduces the impedance of the Na/NiCl2 cells. It is proposed that the use of sodium Iodide enhances the energy and power performance of the NiCl2 electrode by two different mechanisms. The first mechanism, Iodide ion doping of the anodically formed solid NiCl2, is dominant at potentials lower than that of iodine evolution. The doping effect of the Iodide ions produces a higher-capacity, lower-impedance NiCl2 layer on the positive electrode. The second mechanism, anodic formation of very reactive iodine species, is effective when the cell is cycled through the iodine evolution potential range (2.8–3.1 V vs Na). During this process, the dissolved iodine species improve electrode kinetics through liquid-phase mass transport. Use of the sodium Iodide additive is safe in sealed cells, causing no over-pressurizing problems. A maximum pressure increase of only 10 kPa was detected by a pressure sensor during severe overcharge tests.
Tomoya Uruga – One of the best experts on this subject based on the ideXlab platform.
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speciation of iodine in solid environmental samples by iodine k edge xanes application to soils and ferromanganese oxides
Science of The Total Environment, 2006Co-Authors: Sayuri Kodama, Yoshio Takahashi, Kazu Okumura, Tomoya UrugaAbstract:Abstract A method was developed for speciation of iodine in solid materials using X-ray absorption near-edge structure (XANES). This method was used to identify the iodine species (mainly inorganic iodine) in environmental samples. It was shown that the XANES spectra of Iodide and iodate sorbed within solid materials can be simulated by the linear combination of the spectra of Iodide and iodate ions in water. The distribution coefficient ( K d ) between soil and water was obtained independently for Iodide and iodate, based on iodine speciation both in the solid phase, by XANES, and in the aqueous phase, by HPLC-ICP-MS. It was found that the K d of iodate is larger than that of Iodide by a factor of more than six, showing the more soluble nature of Iodide. It was suggested that iodate can form in soil even when Iodide is injected into the soil–water system under conditions within the Iodide-stable field of the Eh–pH diagram of iodine. This is caused by the much higher affinity of iodate for solid surfaces than Iodide. In soil samples under various water saturation conditions, or various Eh conditions, the Iodide fraction in water increases with decreasing Eh, which results in an increase in the dissolved total iodine fraction in soil water. The speciation method using XANES was also applied to iodine in a natural soil sample and marine ferromanganese oxides. It is suggested that iodine K-edge XANES is a promising tool for determining the Iodide / iodate ratio in natural solid samples, which contributes to better understanding of the behavior of iodine at the Earth’s surface.
Lewis E. Braverman – One of the best experts on this subject based on the ideXlab platform.
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Role of iodine in thyroid physiology
Expert Review of Endocrinology & Metabolism, 2010Co-Authors: Angela M. Leung, Elizabeth N Pearce, Lewis E. BravermanAbstract:Adequate levels of iodine, a trace element variably distributed on the earth, are required for the synthesis of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). The Iodide cycle consists of a series of transport, oxidation and coupling steps in thyroid follicular cells to produce thyroid hormone. The sodium/Iodide symporter (NIS) transports Iodide into the thyrocyte. Competitive inhibitors of NIS, such as perchlorate and thiocyanate, can decrease the entrance of Iodide into the follicular cell. Pendrin is the primary protein that is responsible for Iodide efflux out of the thyrocyte and into the follicular lumen. T4 is deiodinated in target tissues to produce the active form of thyroid hormone, T3, and other metabolites. Exposure to excessive iodine or chronic iodine deficiency may result in various clinical disorders. The Wolff–Chaikoff effect and Jod-Basedow phenomenon describe mechanisms of thyroid autoregulation and dysregulation, respectively, during iodine excess. Population studies ha…
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Escape from the Acute Wolff-Chaikoff Effect Is Associated with a Decrease in Thyroid Sodium/Iodide Symporter Messenger Ribonucleic Acid and Protein
Endocrinology, 1999Co-Authors: Guemalli R. Cardona, Shih-lieh Fang, Michael C. Previti, Sharon Alex, Nancy Carrasco, William W Chin, Lewis E. BravermanAbstract:In 1948, Wolff and Chaikoff reported that organic binding of Iodide in the thyroid was decreased when plasma Iodide levels were elevated (acute Wolff-Chaikoff effect), and that adaptation or escape from the acute effect occurred in approximately 2 days, in the presence of continued high plasma Iodide concentrations. We later demonstrated that the escape is attributable to a decrease in Iodide transport into the thyroid, lowering the intrathyroidal iodine content below a critical inhibitory threshold and allowing organification of Iodide to resume. We have now measured the rat thyroid sodium/Iodide symporter (NIS) messenger RNA (mRNA) and protein levels, in response to both chronic and acute Iodide excess, in an attempt to determine the mechanism responsible for the decreased Iodide transport. Rats were given 0.05% NaI in their drinking water for 1 and 6 days in the chronic experiments, and a single 2000-μg dose of NaI ip in the acute experiments. Serum was collected for iodine and hormone measurements, an…
Clemens Walther – One of the best experts on this subject based on the ideXlab platform.
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Sorption of iodine in soils: insight from selective sequential extractions and X-ray absorption spectroscopy
Environmental Science and Pollution Research, 2019Co-Authors: Fabian Köhler, Beate Riebe, Andreas C. Scheinost, Claudia König, Alex Hölzer, Clemens WaltherAbstract:The environmental fate of iodine is of general geochemical interest as well as of substantial concern in the context of nuclear waste repositories and reprocessing plants. Soils, and in particular soil orgaorganic matter (SOM), are known to play a major role in retaining and storing iodine. Therefore, we investigated Iodide and iodate sorption by four different reference soils for contact times up to 30 days. Selective sequential extractions and X-ray absoabsorption specspectroscopy (XAS) were used to characterize binding behavior to different soil components, and the oxidation state and local structure of iodine. For Iodide, sorption was fast with 73 to 96% being sorbed within the first 24 h, whereas iodate sorption increased from 11–41% to 62–85% after 30 days. The organic fraction contained most of the adsorbed Iodide and iodate. XAS revealed a rapid change of Iodide into organically bound iodine when exposed to soil, while iodate did not change its speciation. Migration behavior of both iodine species has to be considered as Iodide appears to be the less mobile species due to fast binding to SOM, but with the potential risk of mobilization when oxidized to iodate.