Vrednovanje industrijskih smola Duolite ARA-9366 i Duolite A-368 na osnovi učinka

This study deals with performance evaluation of nuclear and non-nuclear grade resins Duolite ARA-9366 and Duolite A-368 by application of the radioanalytical technique. The evaluation was made based on kinetics data of ion-isotopic exchange reactions using 131I and 82Br radioactive tracer isotopes. It was observed that under identical experimental conditions of 35.0 °C, 1.000 g of ion exchange resins and 0.002 mol l -1 labelled iodide ion solution, the values of specific reaction rate in min-1 and initial rate of iodide ion exchange in mmol min -1 was 0.173 and 0.044 respectively for Duolite ARA-9366 resin; that was higher than the values of 0.129 and 0.030 respectively reported for Duolite A-368 resins. The identical trend was observed for the two resins during bromide ion-isotopic exchange reaction. The results of this investigation show the existence of a strong positive co-relationship between the amount of ions exchanged and the concentration of ionic solution; as well as the existence of a strong negative co-relationship between the amount of ions exchanged and the temperature of the exchanging medium for both resins. The overall results indicate superior performance of Duolite ARA-9366 over Duolite A-368 under identical experimental conditions.Istraživane su smole nuklearne i nenuklearne kvalitete Duolit ARA-9366 i Duolit A-368 radioanalitičkim metodama. Vrednovanje je temeljeno na kinetici ionske izmjene radioaktivnih obilježivača 151I i 82Br. Pod istim eksperimentalnim uvjetima (35,0 °C; 1,000 g ionskoizmjenjivačke smole; koncentracija jodida 0,002 mol l−1 u obilježenoj otopini) specifične brzine reakcije i početne brzine ionske izmjene bile su 0,173 min−1 i 0,044 mmol min−1 za Duolite ARA-9366, što je više nego 0,129 min−1 i 0,030 mmol min−1 za Duolite A-368. Jednaka tendencija uočena je u izotopnoj izmjeni bromidnog iona. Za obje smole utvrđena je jaka korelacija između množine izmijenjenih iona i koncentracije iona, te jaka negativna korelacija između množine izmijenjenih iona i temperature. Rezultati istraživanja pokazuju veću učinkovitost smole Duolite ARA-9366 od Duolite A-368 pri jednakim eksperimentalnim uvjetima

Sediment Contamination Due to Toxic Heavy Metals in Mithi River of Mumbai

Abstract The present study deals with quantification of accumulated toxic heavy metals in sediments of Mithi River of Mumbai. The study was performed at three different sampling locations along the flow of Mithi River for two years from 2009-12. The different heavy metals studied were Al, As, Cd, Cr, Hg, Ni, Pb, Sr and Mn. The results of our study indicate that the concentration level of these toxic heavy metals for the two assessment years increases by the factor of 1.2-5.8 µg/g. The result is a clear indication of day by day increasing pollution level of the Mithi River, which is creating negative environmental impact on biological life of the river. The results emphasises the need of regular scientific monitoring of different pollutants adversely affecting the environment and to reframe the pollution control strategies already in existence

THERMODYNAMICS OF UNI-UNIVALENT ION EXCHANGE REACTIONS USING STRONGLY ACIDIC CATION EXCHANGE RESIN TULSION T-46

Abstract The study on thermodynamics of ion exchange equilibrium for uni-univalent H + / Na + and H + / K + reaction systems was carried out using strongly acidic cation exchange resin Tulsion T-46. The equilibrium constant K calculated for uni-univalent ion exchange reaction systems were observed to increase with rise in temperature indicating the endothermic ion exchange reactions having the enthalpy values 4.19 and 3.80 kJ /mol respectively