Amount Of Iodide Ion Research Articles

Understanding the Effect of Iodide Ions on the Morphology of Gold Nanorods

AbstractThe presence of iodide ions during the growth of gold nanorods strongly affects the shape of the final products, which is proposed to be due to selective iodide adsorption on certain crystallographic facets. Therefore, a detailed structural and morphological characterization of the starting rods is crucial toward understanding this effect. Electron tomography is used to determine the crystallographic indices of the lateral facets of gold nanorods, as well as those present at the tips. Based on this information, density functional theory calculations are used to determine the surface and interface energies of the observed facets and provide insight into the relationship between the amount of iodide ions in the growth solution and the final morphology of anisotropic gold nanoparticles.

Determination of trace amounts of iodide-ions in water using pulse inverse chronopotentiometry

A technique for metering the microconcentrations of iodide–ions in water using the pulse inverse chronopotentiometry method has been developed. This technique features a sufficient reproducibility and accuracy in terms of metrological certification criteria.

Radiotracer application for characterization of nuclear grade anion exchange resins Tulsion A-23 and Dowex SBR LC

Abstract Radio isotopic tracer technique as one of the versatile nondestructive technique is employed to evaluate the performance of nuclear grade anion exchange resins Tulsion A-23 and Dowex SBR LC. The evaluation was made on the basis of ion-isotopic exchange reaction kinetics by using 131I and 82Br radioactive tracer isotopes. It was observed that for both the resins, the values of specific reaction rate (min−1), amount of ion exchanged (mmol) and initial rate of ion exchange (mmol/min) were calculated to be lower for bromide ion-isotopic exchange reaction than that for iodide ion-isotopic exchange reaction. It was observed that for iodide ion-isotopic exchange reaction under identical experimental conditions of 30.0 °C, 1.000 g of ion exchange resins and 0.001 mol/L labeled iodide ion solution, the values of specific reaction rate (min−1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log Kd were calculated as 0.377, 0.212, 0.080 and 15.5 respectively for Dowex SBR LC resin, which was higher than 0.215, 0.144, 0.031 and 14.1 respectively as that obtained for Tulsion A23 resins. Also at a constant temperature of 30.0 °C, as the concentration of labeled iodide ion solution increases from 0.001 mol/L to 0.004 mol/L, the percentage of iodide ions exchanged increases from 84.75 % to 90.20 % for Dowex SBR LC resins which was higher than increases from 57.66 % to 62.38 % obtained for Tulsion A23 resins. The identical trend was observed for the two resins during bromide ion-isotopic exchange reaction. The overall results indicate superior performance of Dowex SBR LC over Tulsion A23 resins under identical experimental conditions.

Aerobic Oxidation of Cyclohexane on Catalysts Based on Twinned and Single-Crystal Au75Pd25 Bimetallic Nanocrystals.

Bimetallic Au75Pd25 nanocrystals with shapes of icosahedron and octahedron were synthesized by adding different amounts of iodide ions, and were employed as catalysts for solvent-free aerobic oxidation of cyclohexane. Although both icosahedrons and octahedrons were bounded by {111} facets, the turnover frequency number of Au75Pd25 icosahedrons reached 15,106 h(-1), almost three times as high as that of Au75Pd25 octahedrons. The conversion of cyclohexane reached 28.1% after 48 h using Au75Pd25 icosahedrons, with the selectivity of 84.3% to cyclohexanone. Density functional theory calculations along with X-ray photoelectron spectroscopy examinations reveal that the excellent catalytic performance of AuPd icosahedrons could be ascribed to twin-induced strain and highly negative charge density of Au atoms on the surface.

Performance evaluation of anion exchange resins Purolite NRW-5050 and Duolite A-611 by application of radioisotopic techniques

Abstract Radioanalytical techniques using 131I and 82Br as tracer isotopes were applied to study the kinetics of iodide and bromide ion-isotopic exchange reactions taking place between the external labeled ionic solution and the resin surface. The results indicate low values of specific reaction rate (min−1), amount of ion exchanged (mmol) and initial rate of ion exchange (mmol/min) for bromide ion-isotopic exchange reaction as compared to that obtained for iodide ion-isotopic exchange reaction. It was observed that for iodide ion-isotopic exchange reaction performed at 35.0 °C, 1 000 g of ion exchange resins and 0.002 mol/L labeled iodide ion solution, the values of specific reaction rate (min−1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log Kd were 0.340, 0.394, 0.134 and 20.2 respectively for Purolite NRW-5050 resin, which was higher than the respective values of 0.216, 0.290, 0.063 and 18.2 as that obtained by using Duolite A-611. The results of present investigation indicate that during the two ion-isotopic exchange reactions, for both the resins, there exists a strong positive linear correlation between amount of ions exchanged and concentration of ionic solution; and strong negative correlation between amount of ions exchanged and temperature of exchanging medium. From the results it appears that as compared to Duolite A-611 resins, Purolite NRW-5050 resins shows superior performance under identical experimental conditions.

Ion-isotopic exchange reaction kinetics using organic base anion exchange resins Indion-102 and Indion GS-400

The present study deals with the kinetic study of iodide and bromide ion-isotopic exchange reactions in organic based anion exchange resins Indion-102 (nuclear grade) and Indion GS-400 (non-nuclear grade) using radiotracer isotopes. The resins in iodide and bromide form were equilibrated respectively with iodide and bromide ion solutions which were previously spiked with 131I and 82Br radiotracer isotopes. For both bromide and iodide ion-isotopic exchange reactions, it was observed that the values of specific reaction rate increase with increase in ion concentration from 0.001 to 0.004 M at a constant temperature of 40.0°C. However, at constant ion concentration of 0.003 M, the specific reaction rate was observed to decrease with rise in temperature from 30.0 to 45.0°C. Also it was observed that for iodide ion-isotopic exchange reaction by using Indion-102 resin, the values of specific reaction rate, amount of iodide ion exchanged, initial rate of iodide ion exchange and logK d were 0.258 min−1, 0.492 mmol, 0.127 mmol/min and 19.2, respectively, which were higher than 0.208 min−1, 0.416 mmol, 0.087 mmol/min and 17.6, respectively, obtained by using Indion GS-400 resin under identical experimental conditions of 40.0°C, 1.000 g of ion exchange resin and 0.003M labeled iodide ion solution. The same trend was observed for the two resins during bromide ion-isotopic exchange reaction. The overall results indicate that, under identical experimental conditions, Indion-102 resin shows higher performance than Indion GS-400 resin.

Evaluation of anion exchange resins Tulsion A-30 and Indion-930A by application of radioanalytical technique

Radioanalytical technique using 131I and 82Br was employed to evaluate organic based anion exchange resins Tulsion A-30 and Indion-930A. The evaluation was based on performance of these resins during iodide and bromide ion-isotopic exchange reactions. It was observed that for iodide ion-isotopic exchange reaction by using Tulsion A-30 resin, the values of specific reaction rate (min−1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and logKd were 0.238, 0.477, 0.114, and 11.0, respectively, which was higher than 0.155, 0.360, 0.056, and 7.3, respectively as that obtained by using Indion-930A resins under identical experimental conditions of 40.0°C, 1.000 g of ion exchange resins and 0.003 M labeled iodide ion solution. Also at a constant temperature of 40.0°C, as the concentration of labeled iodide ion solution increases 0.001 to 0.004 M, for Tulsion A-30 resins the percentage of iodide ions exchanged increases from 59.0 to 65.1%, and from 46.4 to 48.8% for Indion-930A resins under identical experimental conditions. The identical trend was observed for both the resins during bromide ion-isotopic exchange reactions. The overall results indicate that under identical experimental conditions, Tulsion A-30 show superior performance over Indion-930A resins. The results of present experimental work have demonstrated that the radioanalytical technique used here can be successfully applied for characterization of different ion exchange resins so as to evaluate their performance under various process parameters.

A simple and sensitive analytical method for the determination of thiamine in pharmaceutical preparations

A simple and sensitive method for spectrophotometric determination of thiamine with leucocrystal violet was elaborated. Spectrophotometric quantification based on the following reaction sequence: thiamine was oxidized with potassium iodate(V) to the colourless product and a stoichiometric amount of iodide ions was formed. The latter reacted with the excess of iodate(V) ions in acidic medium, to form free iodine which oxidized leucocrystal violet to the crystal violet dye. The absorbance of the crystal violet dye formed was measured at pH 4.1 ± 0.1 and 589 nm. The measured absorbance obeyed Beer’s law over the thiamine concentration range 0.4-2.4 μg/mL. The linear regression coefficients were a = 0.3339, b = −0.0001, and r = 0.9998 (for the general form of the linear equation y = ax + b). The apparent molar absorptivity of the coloured compound was 1.12 × 105 L/mol cm for thiamine. The limit of detection and limit of thiamine determination were found to be 0.19 and 0.26 μg/mL, respectively. Optimum reaction conditions providing maximum and constant absorbance were optimized. The procedure was successfully used to the determination of vitamine B1 in pharmaceutical formulations. The obtained results were compared with those obtained by the method proposed by Polish Standard.

Comparative Study of Tulsion A-23 and Indion -810 Strongly Basic Anion Exchange Resins By Application of <SUP>131</SUP>I as a Tracer Isotope

The present study is an interesting application of 131I radioactive tracer isotope in characterization of nuclear and non-nuclear grade ion exchange resins Tulsion A-23 and Indion -810. The resins were characterized based on the specific reaction rate (min-1), percentage and amount of iodide ion exchange (mmol) and distribution coefficient values, under identical operating conditions. It is observed that using both the resins, there exist a strong positive correlation between amount of iodide ion exchanged and concentration of iodide ion solution; while a strong negative correlation exist between amount of iodide ion exchanged and temperature of iodide ion solution. The overall results indicate the superior performance of Tulsion A-23 over Indion -810 resins. It is expected that the technique used in the present investigation can be successfully extended to access the performance of different industrial grade ion exchange resins.

Polymorphism and thermal decomposition of [Ni(DMSO)4]I2

Tetrakis(dimethyl sulphoxide)nickel(II) bis(iodide) was studied by thermogravimetry (TG) and simultaneous differential thermal analysis (SDTA) and differential scanning calorimetry (DSC). The gaseous products of the decomposition were on-line identified by a quadrupole mass spectrometer (QMS). Thermal decomposition of the title compound proceeds in three main stages. In the first stage, which starts just above ca. 419 K, the compound loses two dimethyl sulphoxide (DMSO) molecules per one formula unit and small amount of iodide ion. In the second stage (464–552 K) the next DMSO ligands and the iodide ion simultaneously are released. In the last stage (552–900 K) NiSO4 is created which next decomposes to NiO and SO3.

Application of radioactive tracer technique on industrial grade ion exchange resins Indion-830 (Type-1) and Indion N-IP (Type-2)

The radioactive 131I was used as a tracer to study the kinetics of iodide ion-isotopic exchange reactions. The experiment was performed to study the effect of temperature, concentration of ionic solution, and amount of ion exchange resin on kinetics of exchange reactions. It was observed that under different experimental conditions, the initial rate and the amount of iodide ions exchanged calculated for Indion N-IP Type-2 resin were higher than that for Indion-830 Type-1 resins. It is expected that the same technique can be employed to assess the efficiency of various ion exchangers under different operating conditions.

Investigation of ion adsorption on silver sulfide, iodide and bromide precipitates by the radioactive tracer technique

The radioactive tracer method was used to investigate the adsorption of iodide and europium ions from aqueous solution on dried isoelectric precipitates of silver sulfide, silver iodide and silver bromide. The relationship between the amount of iodide ions adsorbed on Ag2S and the iodide ion and HNO3 concentrations in the solution was determined. It was shown that the iodide ions adsorbed on Ag2S could be desorbed with sulfide ions. Using Ag2S, AgI and AgBr precipitates, a relationship between the europium ion adsorption and Eu(NO3)3, H2S, NaI, NaBr and NaCl concentration in solution was established. The adsorption of europium ions was also assessed in respect to the presence of lanthanum and barium ions. For adsorption measurement iodide and europium ions were labeled with their radioactive isotopes and the amounts adsorbed were determined from the measured radioactivities of the precipitates after reaching the equilibrium between the solid phase and the solution.

Ionic components of charge at the mercury-KCl +KI aqueous solution interphase

The ionic components of charge for the mercury aqueous mixtures of KI + KCl interphase have been obtained from capacitance measurements. The experimental results show that the Cl − ion is not specifically adsorbed in the concentration range studied. The specifically adsorbed charge of the iodide ion was obtained by two methods. Grahame's using the Gouy Chapman theory, σ 1 I − (GC) and the method of Parsons—Hurwitz, σ 1 I − (PH). The differences between the two sets is analyzed in terms of the assumptions made in their calculation. The σ 1 I − (GC) shows a crossing point at high σ in the σ 1 I − - vs σ plot. It is explained in terms of an increase in the amount of water at the compact layer and an increase in the amount of iodide ion at the diffuse layer. Other features of the σ 1 I − (GC) vs σ curves are explained in terms of errors of the simple Gouy Chapman model.