Search Results
Abstract
Theoretical possibilities of the preconcentration of solutes in multistage static liquid-liquid extraction have been investigated. It was found that the preconcentration increases with increasing distribution ratio of the solutes between two phases as well as with the number of stages (n) and reaches its maximum value for n approaching infinity, i.e., in dynamic extraction. Comparison of the preconcentration in multistage (Pns) and one-stage (p1s) static operations shows that the relative preconcentration (qns=pns/p1s) increases to infinity as the separation efficiency approaches 100%. Some of these theoretical considerations have been confirmed in extraction of radioiodine from aqueous solutions.
Abstract
The liquid-liquid extraction of about twenty ions with metal diethyldithiocarbamates in chloroform from citrate buffers of pH 2–6 and the most common inorganic acids has been studied. Several backextraction reagents have been examined: hydrochloric acid (1–12M), dilute nitric acid saturated with bromine and a mixture of concentrated hydrochloric acid and hydrogen peroxide. A short review of metal diethyldithiocarbamates as extraction reagents and a mathematical model for these extractions are also included.
Abstract
The liquid-liquid extraction behavior of 2-ethylhexyltolylsulfoxide (EHTSO) towards uranium(VI) contained in nitric acid aqueous solution has been investigated. It was found that the extraction increases with increasing nitric acid concentration up to 5.0 mol/l and then decreases. Extraction also increases with increasing extractant concentration. The extracted species appears to be UO2(NO3)2 .2EHTSO. The influences of temperature, NH4NO3 and Na2C2O4 concentrations on the extraction equilibrium were also investigated and the thermodynamic functions of the extraction reaction were obtained.
and preconcentration step is necessary before determination of analytes by chromatographic methods. Liquid-liquid extraction (LLE) [ 32 ], solid-phase extraction (SPE) [ 33 ] and dispersive-solid-phase extraction (DSPE) [ 34 ] are the most common
Liquid-liquid extraction behaviour of mercury(II) as bromide, iodide and thiocyanate
Separation from Zn(II), Cd(II), Tl(I), Tl(III) and Au(III)
Abstract
The liquid-liquid extraction behaviour of mercury(II) as bromide, iodide and thiocyanate has been investigated in different oxygenated and non-oxygenated solvents. The effects of the molarity of acids, their sodium or potassium salts, the concentration of Hg(II) ions, the temperature and masking anions have been studied. The possibilities of separation of Hg(II) from Zn(II), Cd(II) Tl(I), Tl(II) and Au(III) in these extractions are discussed.
Abstract
The liquid-liquid extraction behavior of uranium(VI) from aqueous nitric acid with bis(octylsulfinyl)ethane (BOSE) in 1,1,2,2-tetrachloroethane has been studied over a wide range of conditions. The extracted species appears to be UO2(NO3)2·2BOSE. It was found that the extraction increases with increasing nitric acid concentration up to 7 mol/l and then decreased. Extraction also increases with increasing extractant concentration. The influence of temperature and salting-out agent concentration on the extraction equilibrium and stripping of uranium(VI) was also investigated and the enthalpy of the extraction reaction was obtained.
Abstract
Amongst various radionuclides of molybdenum, 90Mo and 99Mo have suitable β energy for clinical uses. In this paper we report separation of 99Mo from 99Mo-99mTc equilibrium mixture. The liquid–liquid extraction technique has been employed using trioctylamine (TOA) diluted in cyclohexane as organic phase and HCl as aqueous phase. At 10−5 M HCl and 0.5 M TOA concentration 99mTc quantitatively transferred to the organic phase leaving 99Mo in the aqueous phase. The developed separation method is efficient and provides very high separation factor.
Abstract
A rapid, selective and sensitive liquid-liquid extraction and spectrophotometric method for the separation and microgram determination of uranium using PSAHA is described. Uranium is extracted with PSAHA into chloroform at pH 6.0–6.8. The U-PSAHA chelate is orange red in color having maximum absorbance at 410 nm and molar absorptivity 1.2·104l·mol–1·cm–1. The system obeys Beer's Law in the range of 1.2 to 22.00 ppm of uranium. The uranium is determined in sea water and rock samples.
Abstract
The production of201 Tl is described. Natural thallium is irradiated with protons and the induced201Pb is separated from the target by liquid-liquid extraction with diethyldithiocarbamic acid in chloroform.201Tl is separated from the mother activity (201Pb) by liquid-liquid extraction with the same reagent. The decontamination of the final product (carrier free201TlCl) is ≥5·106 from the thallium of the target and>5×104 from lead isotopes.
Abstract
Liquid–liquid extraction and separation studies of uranium have been carried out from sodium salicylate media using cyanex 272 in toluene. Uranium was quantitatively extracted by 1 × 10−3 M sodium salicylate with 5 × 10−4 M cyanex 272 in toluene. The extracted uranium(VI) was stripped out quantitatively from the organic phase with 1.0 M hydrochloric acid and determined spectrophotometrically with arsenazo(III) at 660 nm. The effect of concentration of sodium salicylate, extractant, diluents, metal ion and strippants has been studied. Separation of uranium(VI) from other elements was achieved from binary as well as from multicomponent mixtures. The method was extended for the separation and determination of uranium(VI) in geological samples. The method is simple, rapid and selective with good reproducibility (approximately ± 2%).
