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 logK _d 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.     

Radiotracers in kinetics of ion-isotopic exchange reactions using anion exchange resins indion-103 and indion-870

The kinetics of iodide and bromide ion-isotopic exchange reactions was studied by radio analytical technique using ¹³¹I and ⁸²Br as tracer isotopes. The parameters like specific reaction rate (min^?1), amount of ions exchanged (mmol), initial rate of ion exchange (mmol/min) and logK _d were studied to evaluate the performance of nuclear and non-nuclear grade anion exchange resins Indion-103 and Indion-870. For iodide ion-isotopic exchange reactions under experimental conditions of 35.0°C, 1.000 g of ion exchange resins and 0.002 M labeled iodide ion solution, the parameters were 0.223 min^?1, 0.300 mmol, 0.067 mmol/min and 18.7, respectively, for Indion-103, and those of 0.165 min^?1, 0.251 mmol, 0.041 /min and 16.2, respectively, for Indion-870. The similar tendency was observed during bromide ion-isotopic exchange reactions. The results suggest that Indion-103 shows greater performance than Indion-870 resin under similar experimental conditions.     

Application of Br-82 as a radioactive tracer isotope to study bromide ion-isotopic exchange reaction in strongly basic anion exchange resin Duolite A-161

In the present investigation Br-82 radioactive isotope was used as a tracer to study the kinetics of exchange reaction taking place between the ion exchange resin and the external bromide ion solution. In an attempt to study the reversible bromide ion-isotopic exchange reaction kinetics, it was expected that whether the initial step was the exchange of radioactive bromide ions from the solution on to the ion exchange resin (forward reaction), or from the ion exchange resin in to the solution (reverse reaction), the two ion-isotopic exchange reactions should occur simultaneously, which was further confirmed from the values of specific reaction rate 0.122 and 0.123 min⁻¹ respectively obtained under identical experimental conditions. The radioactive tracer technique employed in the present investigation will be useful for characterization of various industrial grade ion exchange resins.     

The kinetics and mechanism of bromide ion isotope exchange reaction in strongly basic anion-exchange resin duolite A-162 determined by the radioactive tracer technique

In the present investigation, ⁸²Br radioactive isotope was used as a tracer to study the kinetics and mechanism of exchange reaction between an ion exchange resin and an external bromide ion solution. In an attempt to study the reversible bromide ion isotopic exchange reaction kinetics, it was expected that whether the initial step was the exchange of radioactive bromide ions from the solution into the ion exchange resin (forward reaction) or from the ion exchange resin into the solution (reverse reaction), two ion isotopic exchange reactions should occur simultaneously, which was further confirmed by the experimental specific reaction rates of 0.130 and 0.131 min⁻¹, respectively. The results can be used to standardize process parameters so as to optimize the utilization of ion exchange resins in various industrial applications. The text was submitted by the authors in English.     

The application of the radioactive tracer technique to study the kinetics of bromide isotope exchange reaction with the participation of strongly basic anion exchange resin indion FF-IP

In the present investigation, the ⁸²Br radioactive isotope was used as a tracer to study the kinetics and mechanism of the exchange reaction between an ion exchange resin and an external solution of bromide ions. In an attempt to study the reversible bromide isotope exchange reaction kinetics, it was expected that whether the initial step was the exchange of radioactive bromide ions from the solution to the ion exchange resin (forward reaction) or from the ion exchange resin to the solution (reverse reaction), the two ion-isotope exchange reactions should occur simultaneously, which was further confirmed by the experimental values of specific reaction rates, 0.142 and 0.141 min⁻¹, respectively. The results will be useful to standardize the process parameters so as to achieve optimum use of ion exchange resins in various industrial applications. The text was submitted by the authors in English.     

Protonation and ion exchange equilibria of weak base anion-exchange resins

Protonation and ion exchange equilibria of weak base anion-exchange resins, in which tertiary amine moieties were introduced as a functional group, were investigated by applying NMR spectroscopy to species adsorbed into the resins. ³¹P NMR signals of the phosphinate ion in the resin phases shifted to a lower field due to the influence of protonation of the tertiary amine groups of the resins in the pH range of 4-10. Protonation constants of the tertiary amine groups in styrene-divinylbenzene (DVB)-based resins were estimated to be K_H = 10^6.4 for Amberlite IRA96 and 10^6.5 for DIAION WA30 by the ³¹P NMR method using the phosphinate ion as a probe species. In addition to the low field shift caused by the protonation of the tertiary amine moieties, another low field shift was observed for the phosphinate ion in acrylic acid-DVB-based resins at a rather high pH. This shift should be due to an unexpected deprotonation in the acrylic resin: a tautomerism accompanying the proton release from the amide form to the imide one in the functional group, thus, the resin could exhibit a cation exchange property at the high pH. Protonation constants of the tertiary amine moieties in the acrylic resins were estimated to be 10^8.8 for DIAION WA10, 10^9.0 for Amberlite IRA67 and 10^9.3 for Bio-Rad AG 4-X4 on the basis of the Henderson-Hasselbalch equation using the resin phase pH estimated by the ¹³³Cs and ¹H NMR signal intensities.     

Synthesis of new chiral ionic liquids from α-hydroxycarboxylic acids

New functionalized optically active N-methylimidazolium ionic liquids with an asymmetric center at the β-position to the imdazole ring were synthesized as bromide salts from optically active α-hydroxycarboxylic acids. The bromide anions were exchanged by carboxylate anions with Amberlite IRA 400 ionic exchange resin.     

Determination of Aluminum Traces in Hemodialysis and Tap Water Using Standard Method's Procedure Modified and Flow Injection Ionic Exchange Preconcentration

Abstract

A procedure for the spectrophotometric determination of aluminum traces in water using a flow injection (FI) preconcentration system has been proposed. The flow system was made up of a peristaltic pump, an injector‐commutator, and a minicolumn filled with 300.0 mg of Amberlite IR‐120 cationic exchange resin. After the preconcentration step, aluminum was eluted by a 4.0 mol l^?1 HCl solution. In a second stage, out of the flow system, the eluate was neutralized with a 4.0 mol l^?1 NaOH solution. The aluminum was submitted to the reaction with eriochrome cyanine to form a chelate in solution buffered to pH 5.85, according to the Standard Method's procedure with some modifications, and this was followed by spectrophotometric detection. Chemical and flow variables were studied in the preconcentration system. The precision of the proposed method was calculated for a solution containing 46.8 µg l^?1 of Al(III), when 40.0 ml of solution were preconcentrated (n=7), and their respective relative standard deviation (RSD) was 1.8%. The detection limit obtained was 1.7 µg l^?1 of Al(III) (sample volume=40.0 ml). The proposed method was successful in determining aluminum in water certified reference material.     

Comparative solid phase extraction study on the U(VI) preconcentration by using immobilized thermotolerant <Emphasis Type="Italic">Bacillus vallismortis</Emphasis> and <Emphasis Type="Italic">Bacillus mojavensis</Emphasis>

Bacillus vallismortis and Bacillus mojavensis were loaded onto Amberlite XAD-4 resin and used for solid phase extraction (SPE) of uranium(VI). A quick and simple UV–Vis spectrophotometric method was used to determine U(VI) ion. The best experimental conditions were determined as being a pH of 5.0; a sample flow rate of 2.0 mL min^?1; 200.0 mg of biosorbent; 800 mg of Amberlite XAD-4, and 5.0 mL of 1 mol L^?1 HCl as desorption solution for both immobilized bacteria. The preconcentration factors were achieved as 80 for both solid phase extractor. The developed methods were validated by applying to reference water and tea samples.     

Removal of iodide from aqueous solutions by polyethylenimine-epichlorohydrin resins

The iodide removal from aqueous solutions (initial I^?-concentration: 300–5,000 mg/L) by a low and a high molecular weight polyethylenimine-epichlorohydrin resin was investigated both in absence and presence of background electrolytes (NaCl and Na₂SO₄, ionic strength due to background electrolyte 0.1 M) using a batch technique, ¹³¹I as radioactive tracer and high-resolution γ-ray spectrometry. The experiments in absence of background electrolyte were performed using solutions of initial pH 3 and 7, whereas those in presence using solutions of initial pH 3. The results, which demonstrated the high iodide-removal efficiency of both resins, were modeled using the Langmuir and Freundlich isotherm equations. The experimental data were better reproduced using the Langmuir equation. Using this equation maximum sorption capacity values (Q _max) of 638.8 and 603.3 mg/g were obtained for the high molecular weight resin from solutions of initial pH 3 and 7 respectively, whereas the corresponding values for the low molecular weight one were slightly lower (552.4 and 507.5 mg/g respectively). The iodide uptake by the resins strongly depended on the presence of competing anions and especially of sulfates. The examination of sections of the I-loaded resins grains by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) revealed that iodine was evenly distributed throughout the bulk of the resins and not only bound to their surface.     

Ion Exchange Separation of Platinum and Palladium by Nucleophilic Displacement With Thiocyanate or Thiourea1,2

The separation of platinum and palladium, by adsorption onto weak base anion exchange resins, Amberlite XE 299, or ionex (derived from Amberlite XE-305) from 1M hydrochloric acid, followed by ligand substitution with sulfur nucleophiles is described.

In the thiourea system, cationic thiourea complexes are produced, which cannot be readsorbed into the resin. In the thiocyanate system the formation of Pd(SCN)₄ ^2- is favored in both solution and polymer phases. The Pd(SCN)₄ ^2-. readsorption into the anion exchange resin is the basis for the separation of platinum from palladium.     

Modification of the cation exchange resin properties by impregnation in polyethyleneimine solutions: application to the separation of metallic ions

A commercial cation exchange resin Amberlite 200 has been modified after immersion in solutions of polyethyleneimine (PEI). The kinetic of fixation of the metallic ions have been determined. The modification of the surface of the resin deals with a change in the order of the affinities of the resins towards cations. The retention is the function of the formation and the stability of the complex. The conditions of modification (pH, PEI concentration and time of immersion) have been examined and the modification was confirmed by the determination of the exchange capacities, the distribution coefficient (P) and the selectivity factors (S). The obtained results revealed the effect of PEI on the exchange properties of the resin. The pH range selected (6-8) permitted a good adherence of PEI onto the resin surface. The quantity of the adsorbed PEI was increased by raising the initial concentration and the immersion period. The exchange capacity for copper ion passed from 2.6 mmol g⁻¹, in the case of unmodified resin, to 3.9 mmol g⁻¹ for the modified one.     

Chromatographic separation of thulium from erbium for neutron capture cross section measurements—Part I: Trace scale optimization of ion chromatography method with various complexing agents

The impact of various ion chromatography parameters on the separation of trace amounts of thulium from erbium was examined to address the need for the preparation of a ¹⁷¹Tm target for neutron capture cross section measurements. The following optimal operation parameters for analytical scale separations with cation exchange resin were established based on a modified separation resolution: 0.046 M α-HIB^? as eluent with a flow rate of 1.2 mL min^?1 at 25 °C. Different carboxylic acids with varying pH were also investigated, which reaffirmed the use of α-hydroxyisobutyrate as the most suitable complexant for the separation of these neighboring lanthanides.     

Study of scandium and thorium sorption from uranium leach liquors

Scandium and thorium sorption from simulated uranium leach liquors by phosphorous containing ion exchange resins was studied. Increase of thorium concentration resulted in a decrease of scandium sorption by 26–65%. Tulsion CH 93 resin was chosen for Sc separation from uranium leach liquors. It was shown that 180 g L^?1 Na₂CO₃ allowed for elution 94.1% of Sc and 98.9% of Th in dynamic conditions. Using (NH₄)₂SO₄ (50 g L^?1) + ACBM (180 g L^?1) mixture for primary Sc/Th separation at the resin/eluent ratio of 1:5 resulted in thorium desorption degree as high as 66–69%, whereas scandium loss did not exceed 10%.     

Experimental and FLUKA study relevant to the production of <Superscript>124</Superscript>I through <Superscript>nat</Superscript>Te(p,xn) reaction at a medium-sized cyclotron

A radiochemical methodology for the determination of ⁹⁴Nb in low-level radioactive wastes from nuclear power plant was proposed. Although ⁹⁴Nb is a strong gamma emitter, its concentration in radioactive waste samples is usually several orders of magnitude lower than that of other β–γ emitters, whose emissions interferes in the detection of the emission lines of ⁹⁴Nb. The procedure involves acid digestion, precipitation, cation exchange chromatography by using Amberlite IRA120 resin, extraction chromatography by using TEVA resin to isolate the Nb and the gamma spectrometry to its measurement. The chemical yield was 70% in average. Samples of evaporator concentrate and spent resin were analyzed. For the samples of the evaporator concentrate, the results obtained were below L _D = 9.59 × 10^?4 Bq g^?1. For the spent resin an average result of 1.54 × 10² Bq g^?1 was obtained.     

Determination of Inorganic Anions by Capillary IC Using Hexadimethrine Bromide-Modified Silica Stationary Phases

A simple, rapid and highly sensitive capillary ion chromatographic method for direct determination of iodide and thiocyanate is reported. Separation was achieved on a laboratory-made capillary column (100 mm × 0.32 mm i.d.) packed with silica gel, followed by modification with 20 mM hexadimethrine bromide. Sodium perchlorate?Cmethanol (95:5, v/v) was used as the eluent and analyte anions were detected at 225 nm. Iodate, bromate, nitrate, iodide and thiocyanate were eluted within 8 min, with relative standard deviations of the retention time, peak area and peak height smaller than 2.4%. Effects of the eluent composition on the retention behavior were also investigated. The limit of detection (S/N = 3) of iodide was 6.5 ??g L^?1, whereas that of thiocyanate was 16.2 ??g L^?1. The method was successfully applied to the rapid and direct determination of iodide in powdered milk and thiocyanate in human saliva without any pre-concentration. The modified column could be used for about 1 month (8 h operation per day) without loss of hexadimethrine bromide.     

Effect of metal ion loaded in a resin towards fluoride retention

Indion FR 10 is a commercially available ion exchange resin with sulphonic acid functionality named as H⁺ form, has appreciable defluoridation capacity (DC). It has been chemically modified to La³⁺, Fe³⁺, Ce³⁺ and Zr⁴⁺ forms by incorporating respective metal ions into the resin in order to know their fluoride selectivity by measuring the DC of the respective resin. The maximum DC of these chemically modified ion exchange resins namely La³⁺, Fe³⁺, Ce³⁺ and Zr⁴⁺ forms were found to be 469.7, 467.5, 456.3 and 470.9 mg F⁻/kg respectively suggests their higher selectivity towards fluoride than H⁺ form which has the DC of only 275 mg F⁻/kg at 11 mg/L initial fluoride concentration. The higher DC of the modified resins was explained by electrostatic adsorption and complexation whereas H⁺ form retains fluoride by hydrogen bond. The functional groups present in the sorbents were identified by FTIR and the existence of fluoride onto the resins was confirmed by EDAX analysis. The experimental data was fitted with both Freundlich and Langmuir isotherms. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° indicate that the nature of sorption is spontaneous and endothermic. The applicability of reaction-based and diffusion-based kinetic models was investigated. A field trial was carried out with fluoride water collected from a nearby fluoride-endemic village to test the suitability of these sorbents at field conditions.     

An efficient and selective conversion of sorbitol in ionic liquids: Use of ion exchange resin as a solid acid catalyst

Sorbitol was readily converted by heating in hydrophobic ionic liquids by the presence of ion exchange resins. Chemoseletivity of the dehydration depended on the choice of ion exchange resin; Nafion selectively produced isosorbide while Amberlite gave 1,5-anhydrosorbitol along with unreacted sorbitol. Ionic liquids used in the reaction were readily recovered by simple extraction procedure. With these procedures, we succeeded to prepare isosorbide in pure form, not contaminated with either ionic liquids or acid catalyst, by simple experimental procedure.     

Determination of Vecuronium Bromide in Pharmaceuticals: Development, Validation and Comparative Study of HPLC and CZE Analytical Methods

Vecuronium bromide is a neuromuscular blocking agent used for anesthesia to induce skeletal muscle relaxation. HPLC and CZE analytical methods were developed and validated for the quantitative determination of vecuronium bromide. The HPLC method was achieved on an amino column (Luna 150 × 4.6 mm, 5 μm) using UV detection at 205 nm. The mobile phase was composed of acetonitrile:water containing 25.0 mmol L^?1 of sodium phosphate monobasic (50:50 v/v), pH 4.6 and flow rate of 1.0 mL min^?1. The CZE method was achieved on an uncoated fused-silica capillary (40.0 cm total length, 31.5 cm effective length and 50 μm i.d.) using indirect UV detection at 230 nm. The electrolyte comprised 1.0 mmol L^?1 of quinine sulfate dihydrate at pH 3.3 and 8.0% of acetonitrile. The results were used to compare both techniques. No significant differences were observed (p > 0.05).