Liquid–liquid extraction of Eu(lll) using synergic mixture of 1-phenyl-3-methyl-4-trifluoroacetyl-2-pyrazolin-5-one and crown ethers

Abstract

Synergic extraction of Eu(III) as representative of rare earth elements was conducted with 0.01 mol dm −3 of trifluoroacetylpyrazolin-5-one (HPMTFP) and then with synergic mixture of HPMTFP and crown ethers (benzo-15-crown-5, 18-crown-6, 15-crown-5) in dichloromethane (DCM) from aqueous solution having pH 1.0-3.5. Slope analysis method was used for determining the composition of the synergic adduct i.e. Eu(PMTFP) 3 that came out to be Eu(PMTFP) 3 •2S, where S = neutral oxo-donor and -PMTFP = conjugate base of HPMTFP molecule. Selective extraction of Eu(III) was found in the presence of various masking agents like citrate, oxalate, bromide, thiosulphate, chromate ions and of some cations. The accuracy of the developed procedure was checked by analyzing real lake sample (IAEA-SL-3) as a reference material.

Relative distribution enhancement: a new factor for the evaluation of synergistic solvent extraction

“…Only extractants at the total concentration and their mixtures are required for calculation. Ghani et al 35 . studied the extraction of Eu 3+ with mixtures of HPMTFP and the crown ethers benzo15‐crown‐5 (B15C5), 15‐crown‐5 (15C5) and 18‐crown‐6 (18C6).…”

“… Organic phase: [Reagent] = 0.01 mol L –1 in dichloromethane; aqueous phase: [Eu 3+ ] = 0.003 mol L –1 in nitric media, pH = 2.5 35 …”

“…Synergism has been evaluated by several authors 20,29‐35 with what is called a synergistic factor, R (Eqn (4)): where D mix is the distribution coefficient of the mixed reagents 1 and 2, D 1 is the distribution factor of reagent 1, and D 2 is the distribution factor of reagent 2. The numerical values of this factor report whether the mixture of extractants has synergism ( R > 1), additive effect ( R = 1) or antagonistic effect ( R < 1).…”

“…Synergism has been evaluated by several authors 20,[29][30][31][32][33][34][35] with what is called a synergistic factor, R (Eqn (4)):…”

“…Only extractants at the total concentration and their mixtures are required for calculation. Ghani et al35 studied the extraction of Eu 3+ with mixtures of HPMTFP and the crown ethers benzo15-crown-5 (B15C5), 15-crown-5 (15C5) and 18-crown-6 (18C6). Experiments were carried out at a total concentration of 0.01 mol L -1 for the individual reagents and the mixtures diluted in dichloromethane, avoiding experimental work at a different individual concentration of the reagents.…”