Tri-n-butyl Phosphate Concentration Research Articles

Solvent Extraction of Americium(VI) by Tri-n-Butyl Phosphate

Solvent extraction of Am(VI) by tri-n-butyl phosphate (TBP) from nitric acid solutions was investigated to develop a novel method for partitioning americium from high level liquid waste generated through spent nuclear fuel reprocessing. Am(VI) was prepared using ammonium peroxodisulfate and silver nitrate. The distribution coefficients of Am(VI) were determined for extraction systems of various concentrations of nitric acid and TBP. Sufficiently stable Am(VI) could be extracted and the extraction reaction of Am(VI) was found to be the same as for other hexavalent actinides. The apparent equilibrium constant varied with the concentration of peroxodisulfate used for the valence control, which was ascribed to the competitive reaction of the extraction of Am(VI) and the complex formation of Am(VI) with sulfate ion produced by the decomposition of peroxodisulfate. A distribution coefficient of Am(VI) above 1 was obtained with undiluted TBP and the separation factor between Am(VI) and Nd(III) was 87±9. TBP extraction of Am(VI), after implementing valence control, was proved to be an effective method for the partitioning of americium from fission products such as rare earth elements.

Solvent Extraction of Americium(VI) by Tri-n-Butyl Phosphate.

Solvent extraction of Am(VI) by tri-n-butyl phosphate (TBP) from nitric acid solutions was investigated to develop a novel method for partitioning americium from high level liquid waste generated through spent nuclear fuel reprocessing. Am(VI) was prepared using ammonium peroxodisulfate and silver nitrate. The distribution coefficients of Am(VI) were determined for extraction systems of various concentrations of nitric acid and TBP. Sufficiently stable Am(VI) could be extracted and the extraction reaction of Am(VI) was found to be the same as for other hexavalent actinides. The apparent equilibrium constant varied with the concentration of peroxodisulfate used for the valence control, which was ascribed to the competitive reaction of the extraction of Am(VI) and the complex formation of Am(VI) with sulfate ion produced by the decomposition of peroxodisulfate. A distribution coefficient of Am(VI) above 1 was obtained with undiluted TBP and the separation factor between Am(VI) and Nd(III) was 87±9. TBP extraction of Am(VI), after implementing valence control, was proved to be an effective method for the partitioning of americium from fission products such as rare earth elements.

Thorium Ions Transport across Tri-n-butyl Phosphate—Benzene Based Supported Liquid Membranes

Abstract Transport of Th(IV) ions across tri-n-butyl phosphate (TBP) benzene based liquid membranes supported in microporous hydrophobic polypropylene film (MHPF) has been studied. Various parameters such as variation of nitric acid concentration in the feed, TBP concentration in the membrane, and temperature on the given metal ions transport have been investigated. The effects of nitric acid and TBP concentrations on the distribution coefficient were also studied, and the data obtained were used to determine the Th ions—TBP complex diffusion coefficient in the membrane. Permeability coefficients of Th(IV) ions were also determined as a function of the TBP and nitric acid concentrations. The optimal conditions for the transport of Th(IV) ions across the membrane are 6 mol·dm−3 HNO3 concentration, 2.188 mol·dm−3 TBP concentration, and 25°C. The stoichiometry of the chemical species involved in chemical reaction during the transport of Th(IV) ions has also been studied.

Transport of99mTc across TBP-kerosene oil supported liquid membranes

Transport of99mTc across tri-n-butylphosphate (TBP) kerosene oil supported liquid membranes (SLM) has been studied under various conditions. Presence of dichromate ions helps avoid activity scavenging effects. Concentration increase of TBP, the complexing carrier used in the present study has a positive effect on flux (J) and permeability (P) of these ions, as up to 2.87M there is an increase in J and P values. HCl concentration in the feed solution increases J and P with their maximum values at 2.5–3.0M HCl in the feed. Above this concentration there is a decrease in flux and permeability of99mTc(VII) ions. The given ions are stripped with LiCl or NaCl solutions but more with NaOH. The optimum conditions of transport of the given ions are 2.5M HCl concentration in the feed, 2.87M TBP concentration in the membrane and 1M NaOH concentration in the strip solution. Equations have been developed to indicate the relation between flux, J, viscosity, ν of TBP in organic membrane phase, temperature, T, [H+], in the aqueous feed solutions and Tc ion concentration in the feed solution. Based on P, the values determined from liquid membrane experiments, the quantitative flux values of Tc(VII) ions were also determined as a function of TBP concentration in the membranes, and HCl and Tc concentration in the feed solution using the given equations. This experimental technique provides quantitative results from trace level activity transfer experiments.

Extraction of multi-component system of metals from simulated and industrial effluents by liquid surfactant membranes (LSM)

A study of metal extraction from a multi-component system was carried out by applying a liquid surfactant membrane (LSM) process. The system was an industrial effluent which contains a mixture of metallic species such as Na(I), Mn(II), Co(II), Ni(II), Fe(III) and Cr(III). Concurrently, an analogous research programme was conducted on model solutions reproducing nearly the same physical and chemical composition as the industrial feed. The main goal behind this endeavour was to elucidate the effect of impurities and other components co-existing alongside the metallic species in the industrial feed. Di-2-ethylhexyl phosphoric acid (D2EHPA) was used as a carrier with tri-n-butyl phosphate (TBP). The latter's influence on the kinetics of metal extraction occupied a major part of the investigations. It was found that an optimal composition of the extracting mixture exists (5.5 vol.% D2EHPA + 0.5 vol.% TBP) at which a maximum extraction efficiency can be achieved. It has also been revealed that, although the selectivity is relatively poor, it can be improved by varying the concentration of TBP in the membrane phase. The raffinate kinetic profiles of the simulated solutions have been shown to fit those of the industrial effluent adequately.

Kinetic study of the emulsion breakage during metals extraction by liquid surfactant membranes (LSM) from simulated and industrial effluents

A study on emulsion stability during metals extraction by liquid surfactant membranes (LSM) process has been conducted. The investigations were focused on the emulsion performance during metals permeation from simulated and industrial effluents. To examine the internal aqueous phase leakage which is a symptom of emulsion instability, the internal tracer technique has been applied. The effect of the membrane composition and particularly tri-n-butyl phosphate (TBP) on the stability has been investigated extensively. It has been revealed that, there exists an optimal range of TBP concentrations where a maximum metal extraction and minimum emulsion instability can be achieved. The internal phase leakage model proposed by Boyadzhiev and co-workers has been modified to meet the present system hydrodynamical conditions. The experimental data fit quite well the proposed model.

Transport Study of Hafnium(IV) and Zirconium(IV) Ions Mutual Separation by Using Tri-n-butyl Phosphate-Xylene-Based Supported Liquid Membranes

Abstract A Hf transport study through supported liquid membranes has been carried out to determine flux and permeability data for this metal ion. Tri-n-butyl phosphate (TBP)-xylene-based liquid membranes supported in polypropylene hydrophobic microporous film have been used. These data for hafnium and the previous data for zirconium have furnished the Zr to Hf flux ratio (S) as a function of nitric acid and TBP concentrations of the order of 12 in a single stage at room temperature. Optimum conditions for the separation of these two metal ions appear to be 5–6 TBP mol/dm3, HNO3, concentrations  2.93 mol/dm3, and 10°C. The value of S from an aqueous solution containing 2.4% Hf with respect to Zr has been found to be >125 at 10°C and 1.78 mol/dm3 TBP concentration in the membrane. The technique appears to be feasible for purification of Zr with respect to Hf or vice versa.

Effect of TBP on Solvent Extraction of Np(V) with n-Octyl(pheny1)-N, N-Diisobutylcarbamoylmethylphosphine Oxide

Solvent extraction of Np(V) from nitric acid solution by n-octyl(phenyl)N-N diisobutylcarbamoylmethylphosphine oxide (CMPO) in the presence and absence of tri-n-butyl phosphate (TBP) has been studied using decalin and n-dodecane as diluents. Without the TBP, Np(V) can be extracted using CMPO in decalin with extraction equation: The maximum Np(V) distribution ratio using 0.65 M CMPO in decalin from 2 M nitric acid is 4. The net effect of TBP to CMPO at 2M nitric acid is slight suppression of Np(V) distribution ratio. However, at low CMPO concentration (0.2 M≥) after the Np(V) distribution ratio reaches the minimum value, the distribution ratio gradually increases as the TBP concentration increases. No synergistic interaction of CMPO and TBP has been observed.

The Use of Radioactive Isotopes for the Study of the Metabolism of Certain Biomedically Essential Elements 2. Metabolism of Iron

A systematic study is presented on the extraction of ionic iron from urine. The effect of urine concentration on the extraction from sulphuric acid solutions has been studied by various concentrations of tri-n-butyl phosphate (TBP) as solvent in the organic phase and in the presence of different concentrations of urine in the aqueous phase. Also the effect of carrier free has been studied for extraction by various TBP concentration.

A kinetic model for the extraction of nitric acid by tri- n-butylphosphate

The rotating diffusion cell has been applied to the measurement of the initial rate of mass transfer of nitric acid into tri-n-butylphosphate (TBP) in kerosene. The nitric acid and TBP concentrations were varied between 1 and 10 M and between 15 and 45 vol./vol.% respectively. The model for the flux data incorporates the hydrodynamic features of the technique and allows the calculation of the film mass transfer parameters. Arising from the model a group parameter φ = k r D TBP P TBP 2 is important; it is the physicochemical parameter for the system. The sensitivity of the model and the locale of the reaction are discussed. The value of the partition coefficient P TBP and of the second-order rate constant k r, found from the model, are different from average values expected for the HNO 3/TBP system. It is proposed that the structuring of water at the interface is responsible. It was also found that the overall rate is controlled mainly by diffusion but with a small contribution from the chemical rate.

Tri(n-butyl) phosphate/detergent treatment of licensed therapeutic and experimental blood derivatives.

Incubation of an AHF concentrate with 0.3% tri(n-butyl)phosphate (TNBP) and 0.2% sodium cholate was shown to inactivate at least 10,000 infectious doses of lipid-enveloped viruses, including hepatitis B and non-A, non-B viruses and HTLV-III [Prince et al., Lancet i, pp. 706-710, 1986]. The use of TNBP/detergent combinations for virus sterilization was evaluated further to determine its effect on the structure and function of a wide variety of blood proteins. Vesicular stomatitis and Sindbis viruses were used as markers of virus inactivation. TNBP/detergent treatment did not significantly alter the function of AHF, factor VII, factor IX, factor X, fibrinogen, factor XIII, fibronectin, anti-HBsAg and anti-HA in normal serum globulin, haptoglobin, tumor necrosis factor, alpha-interferon, and both native and chemically polymerized stroma-free hemoglobin. As compared with partially purified derivatives, the extent of virus sterilization of plasma and component cryoprecipitate with 0.3% TNBP and 0.2% sodium cholate at ambient temperature could be improved by raising the TNBP concentration and temperature. Virus sterilization by TNBP/detergent mixtures appears to be generally applicable to blood protein derivatives.

Uranium(VI) transport through tri-n-butylphosphate kerosene oil liquid membrane supported in polypropylene film

Transport of uranyl ions through liquid membranes consisting of tri-n-butylphosphate (TBP) in kerosene oil supported in Celgard 2400 polypropylene microporous film has been studied. Various parameters, such as the effect of nitric acid concentration in the feed solution, TBP concentration in the organic membrane phase, stripping agent concentration and temperature on the flux of uranium across the liquid membrane, have been investigated. The results obtained have been used to elucidate the mechanism of uranium transport and stoichiometry of the diffusing species.

Tri(n-Butyl) Phosphate/Detergent Treatment of Licensed Therapeutic and Experimental Blood Derivatives

Incubation of an AHF concentrate with 0.3% tri(n-butyl)phosphate (TNBP) and 0.2% sodium cholate was shown to inactivate at least 10,000 infectious doses of lipid-enveloped viruses, including hepatitis B and non-A, non-B viruses and HTLV-III [Prince et al., Lancet i, pp. 706-710, 1986]. The use of TNBP/detergent combinations for virus sterilization was evaluated further to determine its effect on the structure and function of a wide variety of blood proteins. Vesicular stormatitis and Sindbis viruses were used as markers of virus inactivation. TNBP/detergent treatment did not significantly alter the function of AHF, factor VII, factor IX, factor X, fibrinogen, factor XIII, fibronectin, anti-HBsAg and anti-HA in normal immune serum globulin, haptoglobin, tumor necrosis factor, a-interferon, and both native and chemically polymerized stroma-free hemoglobin. As compared with partially purified derivatives, the extent of virus sterilization of plasma and component cryoprecipitate with 0.3% TNBP and 0.2% sodium cholate at ambient temperature could be improved by raising the TNBP concentration and temperature. Virus sterilization by TNBP/detergent mixtures appears to be generally applicable to blood protein derivatives.

Vanadium(V) extraction by tri- n-butylphosphate from hydrochloric acid solutions

The extraction of vanadium(V) from HCl solutions into pure and CCl 4 solutions of TBP (tri- n-butylphosphate) has been studied as a function of acid and TBP concentrations. Results suggests that vanadium(V) is extracted as a cationic complex, by an independent mechanism of the extraction of HCl and H 2O. The most likely composition of the organic phase is VO 2Cl·(TBP) 2−3·2HCl·(H 2O) 2−3.

The influence of tri-n-butyl phosphate (TBP) on the kinetics of uranyl ion reduction on the mercury electrode

The adsorption of TBP on the mercury electrode was investigated by impedance measurements in the potential range 0 to −1.5 V vs. 1 M NaCl calomel electrode. The dependence of the rate constants of the reduction of U(VI) ions on the electrode potential and on the concentration of TBP were determined from the polarographic measurements. The tunneling process of the electron transfer across the film of adsorbed molecules of TBP to U(VI) ions is suggested.

The influence of tri-n-butyl phosphate (TBP) on the kinetics of uranyl ion reduction on the mercury electrode

The adsorption of TBP on the mercury electrode was investigated by impedance measurements in the potential range 0 to −1.5 V vs. 1 M NaCl calomel electrode. The dependence of the rate constants of the reduction of U(VI) ions on the electrode potential and on the concentration of TBP were determined from the polarographic measurements. The tunneling process of the electron transfer across the film of adsorbed molecules of TBP to U(VI) ions is suggested.

Investigation of the System: Tri-n-Butyl Phosphate-n-Tetradecane by Gas-Liquid Chromatography

The interaction of tri-n-butyl phosphate (TBP) with various solutes has been investigated by gas-liquid chromatography (GLC). In the case of benzene and chloroalkane solutes, the formation of 1:1 complexes has been assumed. The nonlinear behaviour of partition coefficients of the solutes with high TBP concentration in an inert solvent (n-tetradecane) has been explained in terms of the dimerization of TBP. Infinite dilution activity coefficients of the solutes and the corresponding excess partial molar functions have also been determined between 25.00 and 50.00 degrees C in increments of 5 degrees C.

Rate and equilibrium studies of water transfer at a quiescent interface between water and tri- n-butylphosphate in toluene

The partition of water into tri- n-butylphosphate (TBP) diluted as required with toluene has been studied by means of rate and equilibrium distribution measurements. Initial and subsequent rates were derived for TBP concentrations from 0.4 to 3.65 (pure TBP) mole l. −1 in a stirred mass transfer cell by the quiescent interface method. Equilibrium water concentrations were determined over the range of TBP concentrations from 0 to 3.65 mole 1. −1. Application of a model relating extraction rate to TBP concentration suggests that several hydrates of TBP participate in the transfer. The hydrate composition appears to vary according to the toluene phase TBP concentration. A monohydrate model only fits the equilibrium distribution data at concentrations <0.1 mole l. −1 in TBP. Mechanistic aspects of the model are discussed in relation to further measurements on the variation of transfer rate with individual phase stirring rates and earlier work.

Acidic organophosphorus extractants—XVI Effect of tri- n-butyl phosphate on the extraction of some metals by di-(2-ethylhexyl) phosphoric acid in n-hexane

Tri- n-butyl phosphate (TBP) causes only an antagonistic effect on the extraction of Eu(III), Am(III), Zr(IV) and Nb(V) by di(2-ethylhexyl) phosphoric acid (HDEHP) in n-hexane from aqueous solutions containing perchlorate, citrate and nitrilotriacetate at log [H +] = −2·87 and in extracting Eu(III) from a perchlorate solution at log [H +] = −0·70. A weak synergic effect occurs in the extraction of Sr(II) from solutions containing perchlorate and citrate at log [H +] = −2·87. The complexes Eu A 3 . H A . yB (with A, H A and B denoting the anion of HDEHP, the molecule of HDEHP and the molecule of TBP respectively), Eu A 3 . yB and possibly also Eu A 2(ClO 4) . yB are extracted from 0·2 M HClO 4 + 0·8 M NaClO 4. With 0·10 M citric acid +0·15 M monosodium citrate +0·85 M NaClO 4 as the aqueous phase, the complexes Eu A 3 . 3H A, Am A 3 . 3H A′, Sr A 2 . 2H A. B and Sr A 2 . 2H A . 2 B prevail in the organic phase at the TBP concentration 0·08−0·1 F, while the complexes Eu A 3 . H A . yB, Am A 3 . H A. yB, Sr A 2 . yB, Sr A 2 . H A. yB and probably also Sr A 2 . 2H A . yB are formed at 1·0 F TBP. The value of y in the above complexes could not be determined.

Distribution of sulphuric acid between tri‐n‐butyl phosphate and water

AbstractThe distribution of sulphuric acid between water and 40% by vol. solutions of tri‐n‐butyl phosphate (TBP) in six diluents, and also between water and 40, 60 and 80° solutions of TBP in cyclohexane at 20°, and between water and 40% solution of TBP in cyclohexane and pure TBP at 20°, 30° and 50° has been studied to find the effects of temperature, diluent and TBP concentrations on the extractability of sulphuric acid and on ‘third‐phase formation’.