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Mumbai, India

Radiotracer isotopic technique as an effective analytical tool was used to study the kinetics of ion-isotopic exchange reactions in the nuclear- and nonnuclear-grade anion exchange resins Duolite ARA-9366B and Indion-AGR. On the basis of kinetic data, specific reaction rate (per minute), amount of ion exchanged (millimoles), initial rate of iodide ion exchange (millimoles per minute), and log K d values were calculated for the two resins. It was observed that under identical experimental conditions of 35.0 °C, 1.000 g of ion exchange resins, and 0.002 mol/L of labeled iodide ion solution, the values calculated were 0.200 min-1, 0.278 mmol, 0.056 mmol/min, and 9.6, respectively, for Duolite ARA-9366B resin, which were higher than 0.102 min-1, 0.216 mmol, 0.022 mmol/min, and 5.7, respectively, for Indion-AGR resins. An identical trend was observed for the two resins during bromide ion-isotopic exchange reaction. The overall results indicate that under identical experimental conditions, Duolite ARA-9366B resins show superior performance than Indion-AGR resins. The results of the present experimental work have demonstrated that the radioanalytical technique used here can be successfully applied for the characterization of different ion exchange resins so as to evaluate their performance under various process parameters. © 2013 Springer-Verlag Berlin Heidelberg. Source


The short-lived radiotracer isotopes were applied to study the kinetics and thermodynamic feasibility of iodide as well as bromide ion adsorption reactions using industrial-grade resin materials. Free energy of activation (ΔG‡) and energy of activation (Ea) were calculated by using Arrhenius equation, enthalpy of activation (ΔH‡), and entropy of activation (ΔS‡) calculated by using the Eyring-Polanyi equation. These parameters were used to predict the thermodynamic feasibility of the two ion adsorption reactions performed by using Dowex SBR LC and Indion-810 resins. It was observed that during iodide ion adsorption reactions, the values of energy of activation (−18.79 kJ mol−1), enthalpy of activation (−21.37 kJ mol−1), free energy of activation (58.13 kJ mol−1), and entropy of activation (−0.26 kJ K−1 mol−1) calculated for Indion-810 resins were lower than the respective values of −4.28 kJ mol−1, −6.87 kJ mol−1, 64.97 kJ mol−1, and −0.23 kJ K−1 mol−1 calculated for Dowex SBR LC under similar experimental conditions. Identical trends were observed for the two resins during bromide ion adsorption reactions. The low values of different thermodynamic parameters obtained for Indion-810 resins during both the ion adsorption reactions indicate that the reactions are thermodynamically more feasible using Indion-810 resins as compared to Dowex SBR LC resins. It is expected here that the present nondestructive technique can be extended further for different ions in the solution in order to predict the thermodynamic feasibility of different ion adsorption reactions for the range of resins which are widely used for treatment of industrial waste water effluent. © 2016 Springer-Verlag Berlin Heidelberg Source


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 ionisotopic exchange reaction. The overall results indicate superior performance of Dowex SBR LC over Tulsion A23 resins under identical experimental conditions. © 2015 Carl Hanser Verlag GmbH & Co. KG. Source


This study investigated the levels, sources and potential risks of 17 polycyclic aromatic hydrocarbons in surface sediment samples collected along the Mithi River of Mumbai. The concentration level of σPAHs found in the present study was in the range of 1206-4735 ng/g dw. The composition patterns of PAHs by ring size in sediment were surveyed which indicate the dominance of four rings followed by five and three ring PAHs. In the study it was observed that the high molecular weight PAHs (HMW PAHs) made greater contributions of 90.83% as compared to that of low molecular PAHs (LMW PAHs) contributing to 9.17% to the total PAH concentrations. Toxicity and biological risk were assessed using toxic equivalent quantity and sediment quality guideline quotient. It is feared that the pollution level of PAHs in the sediments might increase in coming times resulting in an unconspicuous risks for the environment and humans through food chains. © 2015 Elsevier Ltd. Source


The present paper demonstrates nondestructive application of the 131I and 82Br radioisotopes in performance evaluation of organic base anion exchange resins Purolite NRW-4000 and Duolite A-378. The evaluation was based on kinetics of iodide and bromide ion-isotopic exchange reactions taking place between the external ionic solution and the resin surface. It was observed that at a constant temperature of 35.0°C when the concentration of bromide ions in solution increases from 0.001 mol/L to 0.004 mol/L, the specific reaction rate values for bromide ion-isotopic exchange increases from 0.228 to 0.266 min-1 using Purolite NRW-4000 resins and from 0.160 to 0.185 min-1 using Duolite A-378 resins. Also it was observed that under the same experimental conditions, the percentage of bromide ions exchanged increases from 60.67% to 67.00% using Purolite NRW-4000 resin, while for Duolite A-378 resin it increases from 49.30% to 52.00%. The identical trend was observed for the two resins during iodide ion-isotopic exchange reaction. The overall results indicate that under identical experimental conditions, as compared to Duolite A-378 resins, Purolite NRW-4000 resins shows superior performance. It is expected that the present nondestructive radiotracer technique can be extended further for characterization of series of nuclear as well as non-nuclear grade ion exchange resins. The results of such study will be immensely useful in proper selection of the ion exchange resins in various industrial applications. © Carl Hanser Verlag, München. © Carl Hanser Verlag GmbH & Co. KG. Source

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