Phosphorous containing radioisotope waste was separated and determined by liquid–liquid extraction method through liquid scintillation
counter (LSC). In this process, ammonium phosphate was converted to phosphomolybdate (PMo) by the reaction of ammonium molybdate
(Mo) in HCl solution (0.02 M) and maximum UV/VIS absorbance (λmax) 218 nm was observed. The PMo solution was extracted with TOA (Tri-n-Octylamine)/xylene mixture and λmax 290 nm was found for this organic layer. Absorbance of aqueous and organic layer was linear through concentration. The impurities
such as Co, Cr, Gd, etc. remain in aqueous layer by treating with Mo which was determined by ICP-AES and AAS. The quenching
correction curve for 32P was calculated using LSC results. No counting change was observed as the volume of quenchers increased. The recovery was
98% and 81% for the extraction and separation process from the test using H332PO4 as standard tracer.
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.
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.
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.
Authors:Yang Yan-Zhao, Sun Si-Xiu, and Feng Sheng-Yu
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.
The extractive properties of the ortho-aminophenol reagent upon U(VI) were investigated in two solvents: 4-chlor-acetophenone
and acetylacetone, in a water-organic solvent system. The method here proposed is based on the complexation reaction of the
uranyl ion, UO22+, with ortho-aminophenol dissolved in 4-chlor-acetophenone, at room temperature, over a pH interval = 4–6, followed by spectro-photometry
of the organic phase, involving measuring of absorbancy at 569.6 nm. The Beer law is valid over the 1–12 μg U(VI)/mL concentration
interval, with molar absorbtivity εmax = 4.3 × 105 mol−1 cm2 and Sandell sensitivity = 0.0526 μg cm−2. The structure, stability and solubility of the formed complex was studied by UV–VIS and IR spectrometry, diffractometry
and scanning electron microscopy. The mixed complex formed between the uranyl ion and the ortho-aminophenol dissolved in 4-chlor-acetophenone,
[UO2.(L)2.(S)4], is characterized by the following parameters: metal/ligand combination ratio: M/L = 1/2, stability constant β = 2.06 × 106, distribution coefficient D = 66.56 (Vorg = Vaq), percentage extraction E% = 98.52, and recovery factor, R%, ranging between 99.48 and 99.85%.
Authors:Sue Chen, Qi An, Hong Sun, and Mengqian Mao
and preconcentration step is necessary before determination of analytes by chromatographic methods. Liquid-liquidextraction (LLE) [ 32 ], solid-phase extraction (SPE) [ 33 ] and dispersive-solid-phase extraction (DSPE) [ 34 ] are the most common
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.
Authors:Yang Yan-Zhao, Yang Yong-Hui, Xong Jun, Sun Si-Xiu, and Bao Bo-Rong
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
Authors:Y. Agrawal, D. Upadhyaya, and S. Chudasama
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.