Iodine

About: Iodine is a research topic. Over the lifetime, 8936 publications have been published within this topic receiving 139981 citations. The topic is also known as: I & element 53.

Iodine and Iodine Compounds

Abstract: The article contains sections titled: 1. Introduction 2. Physical Properties 3. Chemical Properties 4. Occurrence 5. Production 6. Quality Specifications, Transportation, and Storage 7. Uses 8. Economic Aspects 9. Inorganic Iodine Compounds 10. Organic Iodine Compounds 11. Toxicology and Occupational Health

A resonance Raman/iodine Moessbauer investigation of the starch-iodine structure. Aqueous solution and iodine vapor preparations

Abstract: : The structure of the blue-black iodine complex of amylose (the linear, helical component of starch) prepared either from iodine and iodide in aqueous solution or from crystalline amylose and iodine vapor, has been studied by resonance Raman and iodine -129 Mossbauer spectroscopy. In both cases it is concluded that the identity of the major chromophore is essentially the same: the pentaiodide (I(5-1)) anion. For the material prepared from iodine vapor, the iodide required for (I(5-1)) formation is produced by hydrolysis or alcoholysis of iodine. The other product of this reaction, a hypoiodite, has been assigned in the iodine Mossbauer spectrum. (Author)

Removal and sequestration of iodide using silver-impregnated activated carbon.

Abstract: Two silver-impregnated activated carbons (SIACs) (0.05 and 1.05 wt % silver) and their virgin (i.e., unimpregnated) granular activated carbon (GAC) precursors were investigated for their ability to remove and sequester iodide from aqueous solutions in a series of batch sorption and leaching experiments. Silver content, total iodide concentration, and pH were the factors controlling the removal mechanisms of iodide. Iodide uptake increased with decreasing pH for both SIACs and their virgin GACs. The 0.05% SIAC behaved similarly to its virgin GAC in all experimental conditions because of its low silver content. At pH values of 7 and 8 there was a marked increased in iodide removal for the 1.05% SIAC over that of its virgin GAC, while their performances were similar at a pH of 5. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analyses prior to reaction with iodide showed the presence of metallic silver agglomerates on the 1.05% SIAC surface. After the reaction, elemental mapping with EDX showed the formation of silver iodide agglomerates. Oxidation of metallic silver was observed in the presence of oxygen, and the carbon surface appears to catalyze this reaction. When the molar ratio of silver to iodide was greater than 1 (i.e., M(Ag,SIAC) > M(I,TOTAL)), precipitation of silver iodide was the dominant removal mechanism. However, unreacted silver leached into solution with decreasing pH while iodide leaching did not occur. When M(Ag,SIAC) < M(I,TOTAL), silver iodide precipitation occurred until all available silver had reacted, and additional iodide was removed from solution by pH-dependent adsorption to the GAC. Under this condition, silver leaching did not occur while iodide leaching increased with increasing pH.

Changes in thyroidal function during adaptation to large doses of iodide

Abstract: Studies were conducted to determine the mechanism whereby the acute inhibitory effect of large doses of iodide on the organic binding of thyroidal iodide (Wolff-Chaikoff effect) is overcome during prolonged iodide administration (adaptation or escape phenomenon) Thyroids of control rats and of rats adapted to iodide in vivo were freed of inorganic iodide by in vivo administration of thiocyanate and in vitro leaching, and were then incubated in media containing inorganic I/sup 131/ of widely varying specific activity In vitro, when exposed to low concentrations of extracellular iodide, thyroids of control animals accumulated and organically bound more iodine than did adapted glands As the extracellular iodide concentration was increased, the total iodine accumulation in control thyroids increased; however, the quantity of iodine bound organically ultimately declined At this point, ratios of labeled mono- to diiodotyrosine rose Thus, a Wolff-Chaikoff effect was induced in vitro in control glands In adapted thyroids, far less iodine entered the thyroid, but especially at higher concentrations of extracellular iodide, the percentage of accumulated iodide bound organically did not decline so rapidly as in controls As a result, total organic binding rose progressively and, at high iodide concentrations in the medium, exceeded that in control glandsmore » Mono- to diiodotyrosine ratios did not increase Thus, escape from the inhlbitory effects of iodide was evident in vitro in adapted thyroids At each concentration of extracellular iodide, far less inorganic iodide was found in adapted than in control glands, and the concentration of thyroidal iodide achieved by adapted thyroids at the highest medium iodide concentratl ons used was far less than that sufficient to induce the Wolff-Chaikoff effect in control glands In the presence of blocking concentrations of methimazole, the iodidetransport capacity of adapted thyroids was far lower than that of control glands Qualitatively similar data were obtained in studies of the thyroids of control and adapted hypophysectomized rats Administration of thyroid-stimulating hormone to adapted rats did not alter their in vitro iodine metabolism, or their ability to resist the inhibitory effects of high concentrations of extracellular iodide These data suggest that adaptation to the inhibitory effects of large doses of iodide occurs through an intrinsic thyroidal mechanism that reduces the thyroidal iodidetransport capacity and thereby allows intrathyroidal iodide to decline to concentrations insufficient to sustain the Wolff-Chaikoff effect (auth)« less