Sodium Iodide Solution Research Articles

Atomic absorption: another way for phase transition characterization

Phase transitions ocurring in compounds present at ppm levels in powders can be qualitatively and quantitatively observed by atomic absorption spectrometry. Thermodynamic and kinetic aspects of atomic vapour formation during a phase transition are considered. A first generation apparatus for phase transition characterization by atomic absorption spectrometry (PTCAAS) measurements by a fluidized bed technique is presented. As a typical application of this new technique, the determination of ppm amounts of a mixture of mercury(I) and mercury(II) salts in sodium iodide is discussed. The PTCAAS method allows thermal analysis of minor components present in powdered mixtures or as surface layers on solid substrates. By these means one can often obtain data concerning physical state, oxidization state and behaviour during reactions or near equilibrium conditions of low concentration species, for which usual thermal analysis, X ray diffraction or electron microprobe techniques become ineffective. Thus, it could be shown that drying a molar solution of sodium iodide containing less than 10 ppm of sodium iodomercurate results in the formation of solid mercury(I) iodide and correlated destruction of the mercurate complex.

An investigation on ionic solvation by refractometric measurements and electrostatic interaction calculations

Lithium bromide, lithium perchlorate and sodium iodide solutions in acetonitrile, water and methanol have been analyzed by refractometry. Refractive index ( n) and density ( d) measurements provide an experimental value of the mean optical polarizability ḡa of solvated ions as a function of the solvation numbers ( n + and n -). The comparison with ḡa values calculated from a simple additivity model indicates the existence of solvation effects. More complete calculations by a dipole induced dipole method, taking into account interactive electrostatic effects, yield more precise information on the solvation. Thus, in acetonitrile, n + values from 3 to 4 for Li + and about 5 for Na + are evaluated, an ion-pair structure being favoured, in agreement with previous infrared (IR) observations. Moreover, these calculations provide an explanation for the high values of n + observed in previous light scattering experiments. In methanol and water, the expected orders of magnitude are obtained, in particular the change in ḡa values due to solvation in water is very low.

An investigation on ionic solvation by Rayleigh light scattering measurements

Lithium bromide and sodium iodide solutions in acetonitrile have been analysed by Rayleigh light scattering (RLS). Relative depolarized intensity (it r) measurements give the optical anisot- ropy of solvated ions as a function of the total solvation number ( n s = n ++ n −) and allow a lower limit of n sto he obtained. Depolarization ratio (ϱ n) measurements yield more precise determi- nations, for instance n +=5.2 for Li + and 6.4 for Na +, assuming n −=1 for Br − and l −. Infrared (IR) experiments lead to lower n + values for Li + (3–4). Higher values of n s in RLS can be due to the second shell of coordination beyond the cation which is not detected by IR absorption.

LDV MEASUREMENTS OF SOLID-LIQUID SLURRY FLOW USING REFRACTIVE INDEX MATCHING TECHNIQUE

ABSTRACT A refractive index matched facility for studying solid-liquid slurry flow was developed. The refractive index matching of the solid and liquid facilitates the use of non-intrusive—laser velocimetry to measure solid and liquid velocities for slurries with solid concentrations as high as 50 percent by volume. Silica gel and sodium iodide solution in water were used us the refractive index matched solid and liquid respectively. Tests were conducted on solid liquid slurry with 5 percent solid concentration by volume in the Reynolds number range of 700 to 8000. The Reynolds number ranges for the four flow regimes, stationary bed, saltation, heterogeneous and homogeneous flow were identified. It was shown that signal processing technique utilizing histograms and signal amplitude discrimination can be used to discriminate between liquid and solid velocities. The details of the facility and the results of the tests conducted on the slurry are discussed in this paper.

Heat of solution and electric conductivity of electrolytes in water–tetrahydrofuran mixtures

Integral heats of solution of sodium perchlorate (NaClO4) in water–tetrahydrofuran (THF) mixtures from 0 to 100 mol% THF have been measured. The electric conductivity of NaClO4 solutions in binary solvents containing from 0 to 80 mol% THF have also been measured, as have the conductivities of solutions of sodium chloride (NaCl) and sodium iodide (NaI) in mixtures containing from 0 to 35 mol% THF. Molar electro-conductivities, Walden products and association equilibria constants have been determined. Taking into account ion-pair association, standard enthalpies of solution have been recalculated.

ChemInform Abstract: Electrical Conductivities of Halide Salts in Aqueous Formamide Solutions.

The electrical conductivities of sodium chloride and sodium iodide solutions in formamide-water mixtures of different composition have been measured at 25°C. From these data, the limiting equivalent conductances for these salts have been determined. The correspondingWalden products are compared together with the one reported for sodium bromide in the same solvent mixtures, and they are analysed as functions of the anion size. Further, the limiting ionic equivalent conductances are estimated for the different ions. The variation of the ionicWalden products with solvent composition is discussed in terms of ionic solvation and solvent structure.

Electrical conductivities of halide salts in aqueous formamide solutions

The electrical conductivities of sodium chloride and sodium iodide solutions in formamide-water mixtures of different composition have been measured at 25°C. From these data, the limiting equivalent conductances for these salts have been determined. The correspondingWalden products are compared together with the one reported for sodium bromide in the same solvent mixtures, and they are analysed as functions of the anion size. Further, the limiting ionic equivalent conductances are estimated for the different ions. The variation of the ionicWalden products with solvent composition is discussed in terms of ionic solvation and solvent structure.

Determination of inorganic and organotin compounds in sea water by graphite furnace atomic absorption spectrometry

Inorganic tin and organotin compounds in artificial sea water were determined at sub-p.p.b. levels. These compounds are separated from matrix elements in aqueous solutions by benzene extraction of their iodide forms from a 2 M sulphuric acid-1.5 M sodium iodide solution containing 1%m/V ascorbic acid. The organic phase was partially vaporised to pre-concentrate the analytes and was injected directly into the treated graphite tube; the signal was measured by a Zeeman atomic absorption spectrometer. Using a matrix modifier, inorganic tin could be directly determined at sub-p.p.m. levels in the presence of organotin compounds.

The colligative properties of certain electrolytes and non-electrolytes in methanol

Osmotic coefficients for methanol solutions of sodium iodide are calculated from recently published vapor pressure data. These data furnish a reference solute for other isopiestic studies in this solvent. Data are reported for three additional electrolytes and two non-electrolytes. These data are compared with the osmotic coefficients of the same solutes in water to illustrate and in some instances to elucidate the relative importance of various interactions in solutions.

Enhancement of protein synthesis by neuroblastoma cells exposed to ultrasound cavitation

Enhancement of the cavitational effect of iodine release from sodium iodide solution during repetitive 1‐MHz tone burst excitation of the solution of a rotating test tube has been reported. [V. Ciaravino, H. G. Flynn, and M. W. Miller, Ultrasound Med. Biol. 7, 159–166 (1981)]. This enhancement was attributed to concurrent operation of two mechanisms: depletion of small nuclei from the cw mode size distribution generated during a tone burst, and survival from the previous tone burst of small nuclei lying in the same size range that is depleted in the cw mode. Twenty‐four hours after exposing C1300 neuroblatoma cells (N2A) in rotating tubes to 1‐MHz ultrasound tone bursts [1:1, durations from 6 to 600 ms; 3.4 W/cm2 spatial peak, burst average intensity, and 5 min total treatment duration (on + off periods)] at 37°C, enhancement of protein synthesis compared to control cells was observed. Protein synthesis was measured by uptake of 3H‐leucine. The similarity between results observed for cavitation‐stimulated iodine release and cellular protein synthesis is highly suggestive of cavitation as the cause for this biological effect. [Work supported by PHS.]

Vapor pressure measurements on non-aqueous electrolyte solutions. Part 3: Solutions of sodium lodide in ethanol, 2-propanol, and acetonitrile

Precise vapor pressure data for solutions of Nal in ethanol from 0.04 to 1.9m, and 2-propanol and acetonitrile from approximately 0.06 to 1.5m are communicated and discussed. Polynomials in molalities are given for calculating precise reference values. Osmotic coefficients were calculated by taking into account the second virial coefficients of solvent vapors. Discussion of the data at low concentrations is based on the chemical model of electrolyte solutions and ion-pair association constants are compared to those obtained from other properties of sodium iodide solutions. Pitzer equations are used to reproduce osmotic and activity coefficients at high concentrations; the set of Pitzer parameters for methanol solutions b=3.2, α1 = 2.0, and α2 = 20.0 may be used for ethanol, 2-propanol, and acetonitrile solutions.

Synthesis, structure and low temperature magnetism of the new lithium and sodium insertion compounds: LiFe(II)ClMoO 4 and NaFe(II)ClMoO 4

The recently described tetragonal layered compound Fe(III)ClMoO 4 is found to undergo reversible lithium and sodium ion insertion by stirring the solid in an acetonitrile solution of lithium or sodium iodide under argon. Reaction occurs via a topochemical redox-insertion mechanism where Fe 3+ is reduced to Fe 2+. LiFe(II)ClMoO 4 is monoclinic with a = 6.9944(6), b = 6.8712(6), c = 5.0146(5) A ̊ and β = 91.270(5)° (space group P2 I/m). NaFe(II)ClMoO 4 appears to be orthorhombic with a = 7.174(2), b = 7.185(1) and c = 5.183(1) A ̊ . The structure of LiFe(II)ClMoO 4, determined by a Rietveld refinement of neutron powder diffraction data, is essentially the same as that of the precursor and contains Li ions in distorted octahedral sites between the layers. Also, the Fe atoms are shifted to a position where they are 6-coordinated compared to the 5-coordination observed in the ferric precursor. Zero field Mössbauer spectra for the lithium compound undergo hyperfine splitting that corresponds to a three-dimensional magnetic ordering process with T Néel∼ 68.5K. Low-dimensionality antiferromagnetism (probably one-dimensional chain in nature) is evident as a, broad maximum in the D.C. susceptibility at Tχ max ∼ 73 K. This is approximately 30 kelvins less than a similar low-dimensionality maximum observed in χ m for the ferric precursor. Mössbauer spectra for the sodium insertion compound suggest cooperative three- dimensional magnetic order below ∼ 45 K.

Studies of the ion distribution in the surface of a liquid solution of sodium iodide in tetramethylguanidine–water using electron spectroscopy

Enhanced signals from sodium iodide in tetramethylguanidine containing water indicate that sodium and iodide ions are concentrated in the surface layer of the liquid solution.

Calorimetric investigation of NaI–alcohol interactions in alcohol + alcohol mixtures

Enthalpies of solution of sodium iodide in mixtures of methanol with ethanol, n-propyl alcohol and isopropyl alcohol have been measured at 298.15 K over the entire range of mixture compositions. Standard solution enthalpies exhibit maxima in the region of high n-propyl alcohol and isopropyl alcohol contents in the system, while in the case of the methanol + ethanol system the standard enthalpy has a monotonic character. Enthalpic NaI–alcohol pair-interaction coefficients for the systems under study have been calculated and analysed.

Ion Exchange from a Nonaqueous Solution. Zinc (II) Bromide and Iodide in Ethylene Glycol

Abstract The distribution behavior of the zinc ion in sodium bromide and iodide solutions between the cation-exchange resin for forced-flow liquid chromatography and the absolute or aqueous ethylene-glycol phase was investigated radiometrically. From the experimental data, consecutive complex formation constants for zinc bromide and iodide in the glycol have been calculated by the nonlinear least-squares method. The results are as follows: in absolute glycol β1Br=2.60 and β2Br=3.91 for zinc bromide, β1I=2.36 and β2I=3.04 for zinc iodide; in 5 wt% aqueous glycol β1Br=2.30, β2Br=3.32, and in 10 wt% aqueous glycol, β1Br=1.87, β2Br=2.78, respectively.

Turbulence Structure and Heat Transfer of Pipe Flow with Cascade Smooth Turbulence Surface Promoters

Turbulent flow structure and heat transfer in a pipe with arc shaped cascade turbulence surface promoters are experimentally studied for applying to the thermoelectric ocean thermal energy conversion (OTEC). Mean velocities and turbulence properties such as turbulence energy and Reynolds shear stress are measured by the one color laser Doppler velocimeter with Bragg cell. To exactly measure the whole flow field, especially the one around the promoter, a glass tube with a smooth rib and water solution of sodium iodide having the same refrative index as the pipe material are used as the test section and the working fluid, respectively, to prevent the refraction of the laser beam at the interface between them. Relations among turbulence energy, Reynolds shear stress, pressure loss and local heat transfer conefficient are discussed on the basis of the experimental results for the different rib heights.

Peculiar properties of sodium lodide in alcohols, acetone, and alcohol-water mixtures at lower temperatures

The enthalpies of solution of sodium iodide in methanol, ethanol and acetone and in mixtures of methanol and ethanol with water were measured over wide ranges of electrolyte concentration and temperature. Standard enthalpies of solution, transfer enthalpies of NaI from alcohols to alcohol-water mixtures, and temperature coefficients of enthalpies of solution have been calculated. Thermodyanmic characteristics of solution and solvation of the Na+ and I− ions in acetone and ethanol were determined at 243–298 K. It is noted that at lower temperatures the disruption of solvent structure by ions is a local effect. The presence of negative solvation of the Na+ and I− ions in alcohol-water mixtures at lower temperatures is demonstrated.

Ultrasonic Absorption in Solutions of Sodium Iodide in Isopropyl Alcohol and Isopropyl Alcohol–Water Mixtures

Abstract Ultrasonic relaxational absorption was observed in solutions of NaI in i-PrOH. Assuming the excess ultrasonic absorption to be caused by the relaxation of the dissociation equilibrium of NaI in the solutions, the dissociation and recombination rates of NaI, the Arrhenius activation energy, and the enthalpy and volume changes due to dissociation were calculated; these were compared with the values estimated from other methods. An increase of the dissociation constant of NaI was observed with an increase in the concentration of H2O in i-PrOH–H2O mixtures.

Ionic B coefficients in water at 30, 40 and 50 °C

Viscosity measurements of aqueous solutions of sodium chloride, sodium bromide, sodium iodide, sodium perchlorate, sodium tetraphenylborate, tetraphenylphosphonium bromide, tetrabutylammonium bromide and tri-isoamylbutylammonium iodide at 30, 40 and 50 °C are reported. By means of a new method for separating the viscosity B coefficients of the Jones–Dole equation based on BBPh–4=BPPh+4, the ionic values B± at 30, 40 and 50 °C were calculated. This new method is compared with other separation methods and the variation of the ionic B coefficients with temperature is discussed.

Penetration of protective gloves as a route of intake for tritiated water and 125I-labelled sodium iodide solution

Measurements have been made of the rate at which tritiated water and 125I-labelled sodium iodide solution penetrate various types of protective gloves, both isotopes being in common use in this form in universities and similar establishments. Diffusion coefficients relating to the glove materials are also determined. The health physics aspects are discussed and it is concluded that intakes by workers through intact gloves are not likely to be of major significance and can be easily be minimised by the correct use and choice of glove.