Tri-n-butyl Phosphate Concentration Research Articles

Study of the Chemical Recovery and Selectivity against U in the Radiochemical Separation of Th with Tri-n-butyl Phosphate by Varying the Proportion of Xylene and HCl Concentration.

Thorium is a radionuclide used in various environmental studies such as dating, sediment movement, soil-plant transfer studies, and contamination of waste from the natural fuel cycle. The liquid-liquid extraction method using tri-n-butyl phosphate (TBP) allows for the separation of Th from the accompanying actinides. However, the separation of Th and U present in the same sample is not trivial. This separation is influenced by the starting acid (HCl or HNO3), the concentration of TBP in an organic solvent, and the concentration of the acid used for re-extracting Th, which is typically HCl. Therefore, it is necessary to study these factors to ensure that the method has sufficient chemical yield and selectivity in complex matrices. This study presents a systematic investigation of the aforementioned parameters, making the necessary variations to select an optimal method for the radiochemical separation of Th. The ideal conditions were obtained using 4 M HCl as the acid prior to extraction, a 1:4 solution of TBP in xylene, and 4 M HCl as the re-extracting agent. The accuracy and precision were studied in four intercomparison exercises conducted in quadruplicate, using the parameters Enumbers, RB(%), and RSD(%) for 232Th and 230Th. The sensitivity of the method was experimentally studied and the limit of detection (LoD) was determined according to ISO 11929:2005. Additionally, the linearity of the method showed that the experimental and theoretical activity concentrations of 232Th and 230Th had slopes of 1 with an intercept close to 0.

Parametric optimization of separation of succinic acid in groundnut oil with Tri‑n‑butyl phosphate using response surface methodology with central composite design

ABSTRACT Succinic acid (SA) is a platform chemical for producing biofuel and other green chemicals. Fermentative SA production is a cost – effective and eco – friendly method, with quite a few downstream challenges. The recovery method of reactive extraction shows promise but faces toxicity issues with the diluent and extractant, especially concerning microorganisms in the fermentation broth. Hence, a non – toxic diluent and extractant, or less toxic combinations, are needed for efficient acid recovery. Hence, non – toxic diluents, groundnut oil and sesame oil, were evaluated. Based on the superior extraction efficiency (E%) achieved with groundnut oil, the study conducted reactive extraction of SA from the aqueous phase using tri-n-butyl phosphate (TBP) dissolved in groundnut oil. Using response surface methodology with central composite rotatable design, E% was maximized by optimizing independent variables, which were: initial SA concentration– 0.2525 mol L−1, TBP concentration in groundnut oil as the extractant– 50%, shaking time–4 h, pH– 3. These conditions resulted in a distribution coefficient of 0.951 and E% of 48.75%, which are closely aligned with the predicted values of 0.953 and 50.21%, respectively. Fourier Transform Infrared Spectroscopy analysis confirmed a 1:1 complex formation in the organic phase. The results provide insights into the efficient recovery of SA from the fermentation broth.

Density Equation for Mixed Organic Solutions Containing tri-n-butyl Nitrate, n-Dodecane, Nitric Acid, and Nitrates of Heavy Metals

Several empirical equations were available in the literature for density equation for tri-n-butyl phosphate (TBP)–bearing mixed organic solutions used in the PUREX/UREX process; however, all most all of the equations were found to have a limited range and a limited number of solutes to be handled. In this work, a robust density equation is proposed in a dimensionally consistent manner. In the proposed equation, TBP is also considered as a solute, rendering the proposed equation valid over a full range of TBP concentrations. The highlights of this technical note include 1. Density equation for mixed organic solutions, containing TBP, n-dodecane, and nitrates of heavy metals, is proposed in a dimensionally consistent manner. 2. TBP is also considered as a solute, rendering proposed equation valid over 0% to 100% of TBP concentrations. 3. The proposed equation is valid for uranium concentrations 0 to 120 g/L in organic phase. 4. With a small loss of precision, the same can be used for PUREX solvent loaded with Pu(IV).

Exposure to environmentally relevant concentrations of TnBP results in tissue-specific bio-accumulation and inhibits growth of silver carp (Hypophthalmichthys molitrix)

Tri-n-butyl phosphate (TnBP) is commonly used as flame retardant and rubber plasticizer, and has been widely detected in aquatic organisms and natural waters. However, the potential toxicity of TnBP in fish remains unclear. In the present study, silver carp (Hypophthalmichthys molitrix) larvae were treated with environmentally relevant concentrations (100 or 1000 ng/L) of TnBP for 60 d and then they were depurated in clean water for 15 d, and the accumulation and depuration of the chemical in six tissues of silver carp were measured. Furthermore, effects on growth were evaluated and potential molecular mechanisms were explored. Results indicated that TnBP could be rapidly accumulated and depurated in silver carp tissues. In addition, the bio-accumulation of TnBP displayed tissue-specificity, where intestine contained the greatest and vertebra had the smallest level of TnBP. Furthermore, exposure to environmentally relevant concentrations of TnBP led to time- and concentration-dependent growth inhibition of silver carp, even though TnBP was completely depurated in tissues. Mechanistic studies suggested that exposure to TnBP up- and down-regulated the expression of ghr and igf1 in liver, respectively, and increased GH contents in plasma of silver carp. TnBP exposure also up-regulated the expression of ugt1ab and dio2 in liver, as well as decreased T4 contents in plasma of silver carp. Our findings provide direct evidence of health hazards of TnBP to fish in natural waters, calling for more attention of environmental risks of TnBP in aquatic environment.

Effect of TBP on the Coordination Process of Eu(III) with T2EHDGA: A Luminescence Spectroscopy Investigation

AbstractIn this report, we explore the precise responsibility of a phase modifier along with the prime ligand in the coordination process of Ln(III) ions using luminescence spectroscopic technique by taking Eu(III) as the probeing metal ion. A well accepted diglyoclamide (DGA) ligand: N,N,N’,N’‐ tetra(ethylhexyl)diglycolamide(T2EHDGA) was used as the prime extractant along with tri‐n‐butylphosphate (TBP) as the phase modifier. Meticulous investigations on Eu(III) complexation with T2EHDGA‐TBP binary mixture was pursued by employing luminescence spectroscopy with the systematic variation of the concentration of TBP in the ligating phase and initial concentration of Eu(III) in the feed phase. The dominancy of the LMCT band over that of the metal centered band signifies the structural difference in the ligands used in the study. The presence of TBP in the organic phase enhances the intensity of 5D0→7F2 and 5D0→7F0 transition. The excitation and emission patterns of the Eu(III)‐solvate species formed in the organic phase both in unirraditaed and irradiated conditions were found to be entirely different, which effectively corroborates the efficacy of the extracting phase. The asymmetry ratio (AR) and the life time data at each experimental conditions were ascertained to realize the coordination behavior of the Eu(III) complex in the organic phase.

Recovery of valeric acid using green solvents

AbstractIn this work, extraction of valeric acid (VA) using tri‐n‐butyl phosphate (TBP) as a reactive extractant was carried out. To reduce the toxic effects of the conventional diluents on microorganisms, non‐toxic and green edible sunflower and soybean oils were tried as the diluents. The high values of the distribution coefficient and extraction efficiency advocated to use them in the bio‐refinery industries. Moreover, it shows intensification of the recovery of VA using reactive extraction process. Sunflower oil appeared to be a better diluent than soybean oil. The complexation reaction stoichiometry (m and n) and equilibrium complexation reaction constant were estimated by using the differential evolution technique. In spite of the loading ratio being less than 0.5, the estimated m/n was found to be more than 1.0. The higher values of occurred due to the 9higher stability of the VA‐TBP complex in sunflower oil than in soybean oil. The stoichiometry of VA decreased with increasing TBP concentration. The complex concentration, , was found to be higher for soybean oil. It increased with temperature and initial VA concentration but remained invariant with TBP concentration. Due to the decreasing trend of with temperature, the complexation reaction became exothermic. The enthalpy changes due to mass transfer stipulated easier mixing of the phases in sunflower oil than in soybean oil.

Hydrolysis of tri-butyl phosphate in n-dodecane using sodium hydroxide: Factors affecting the hydrolysis process

Alkaline hydrolysis of tri-n-butyl phosphate (TBP) in n-dodecane (n-DD) using sodium hydroxide was studied for the treatment and disposal of spent organic waste generated from nuclear reprocessing plants. Experiments were performed in a stainless steel autoclave with a process volume of about 1 L to investigate the effect of agitator speed, temperature, organic to aqueous phase ratio, and concentration of sodium hydroxide on the kinetics of TBP hydrolysis. The concentration of TBP gradually decreased with increase in the duration of hydrolysis followed by a sharp fall in the concentration of TBP due to autocatalytic hydrolysis of TBP. The diluent does not take part in the hydrolysis reaction which was evident from the third phase formation during the course of hydrolysis. The present study confirms the complete conversion of TBP to its aqueous soluble products during hydrolysis. The results showed that among the various parameters studied, the concentration of NaOH and temperature were the key factors in determining the rate of hydrolysis of TBP. By using 12.5 M NaOH, aqueous phase to organic phase ratio above 1/3, temperature above 353 K, at an agitation speed of 1000 rpm, nearly complete hydrolysis of 1.1 M TBP was achieved in less than 3 h.

A systematic approach for achieving the maximum loading of Eu(III) in TODGA/n-dodecane phase with the aid of TBP phase modifier

Determining the stoichiometry of Eu(III) to N,N,N′,N′-tetraoctyldiglycolamide (TODGA) in the organic phase containing TODGA in n-dodecane (n-DD) is a challenging job due to the formation of third phase prior to the maximum loading of Eu(III) in the organic phase. The phase modifier tri-n-butyl phosphate (TBP) has been added to the organic phase to minimize and prevent the undesirable third phase formation. Even though the added TBP prevented the third phase, the loading behavior of Eu(III) in TODGA + TBP/n-DD and the role of TBP in altering the stoichiometry of Eu(III) to TODGA is unknown so far. To unravel the role of TBP at higher loadings of Eu(III) in the organic phase, the extraction behaviorof Eu(III) from nitric acid solution was studied in a solution of 0.1 M TODGA + TBP/n-DD. The concentration of nitric acid and Eu(III) in aqueous phase, and TBP concentration in organic phase were varied in those investigations to determine the maximum loading of Eu(III) and stoichiometry of Eu(III) to TODGA in organic phase. The results revealed that the Eu(III) to TODGA stoichiometry of 1:1 could be achievable at higher concentrations of TBP in the organic phase (> 1 M), which served as a sacrificial proton acceptor during extraction. The results were supported by FTIR investigations in the loaded organic phase.

Transcriptomics and metabolomics reveal Ca2+ overload and osmotic imbalance-induced neurotoxicity in earthworms (Eisenia fetida) under tri-n-butyl phosphate exposure

Tri-n-butyl phosphate (TNBP) is mass-produced and widely utilized in many products, which has increasingly drawn concern about its potential environmental risks. However, little is known about the toxic mechanism on soil-dwelling organisms caused by TNBP. In this study, earthworms (Eisenia fetida) were exposed to environmentally relevant or higher concentrations of TNBP (0, 0.1, 1, and 10 mg/kg) in artificial soil for 14 days. Our results showed that TNBP accumulated in earthworm nervous tissue (cerebral ganglions). In addition, the content of glutamate in cerebral ganglions decreased compared to the control (p < 0.05). The concentration of Ca2+ in earthworm cerebral ganglions increased. However, both Na+/K+-ATPase and Ca2+-ATPase activities were significantly reduced compared to the control (p < 0.05), which led to neurotoxicity in earthworm nervous tissue. Furthermore, the transcriptome and metabolomics revealed the toxic mechanism in earthworm nervous tissue caused by TNBP. Results indicated that the main neurotoxicity mechanisms induced by TNBP were an osmotic imbalance and Ca2+ overload in cerebral ganglions. Our findings fill a gap in the literature on neurotoxicity mechanisms of earthworm response to TNBP exposure and contribute to a better understanding of the adverse effects of TNBP on soil-dwelling organisms in terrestrial ecological systems.

Understanding the Mechanism of Lithium Ion Extraction Using Tributyl Phosphate in Room Temperature Ionic Liquid

ABSTRACT This paper reports the liquid-liquid extraction behavior of lithium ions from aqueous solutions containing hydrochloric acid using a well-known neutral extractant tri-n-butyl phosphate (TBP) and commonly used imidazolium-based ionic liquids (IL). The effect of several experimental parameters on the lithium partitioning was examined, in particular the nature of counter anions, the concentration of TBP, the pH of the aqueous solutions, and the initial lithium ion concentration. The lithium extraction was also investigated with a conventional organic solvent 1-octanol to understand the role of the IL in the extraction process. Our results suggest that lithium partition into TBP/IL system proceeds via two mechanisms, namely by cationic exchange and ion pair transfer. The corresponding extraction equilibrium constants as well as stoichiometry of extracted complexes were determined. To overcome the loss of ionic liquid by cation exchange, we have shown that TBP mixed with an ionic liquid possessing low solubility in aqueous phases can extract lithium when a highly hydrophobic counter-ion such as () is present in the aqueous phase.

The role of surfactant force field on the properties of liquid/liquid interfaces

Surfactant-laden liquid/liquid interfaces mediate numerous chemical processes, from commercial applications of microemulsions to chemical separations. Classical molecular dynamics simulation is a prevalent method for studying microscopic and thermodynamic properties of such interfaces. However the extent to which these features can be reliably predicted, and the variations in predicted behavior, depend upon the force field parameters employed. At present, the impact of force fields upon simulated properties is relatively understudied. Yet recent advances to sampling and analysis algorithms are increasing the interpretation of simulation data and therefore understanding force field dependence is increasingly relevant. In this study, the impact of the force field of the surfactant tri-n-butyl phosphate (TBP), as well as that of water, is investigated at a water/(n-hexane + surfactant) interface. Empirical charge scaling was employed to modulate the hydrophilicity of the surfactant. As anticipated, the relative hydrophilicity of TBP influences a number of properties, including the adsorbed concentrations of TBP at the interface, and macroscopic properties that result from hydrogen bonding interactions, such as interfacial tension and width. The dynamic properties of solvents at the interface are strongly modulated by the variation in hydrogen bond strength caused by different charge scalings of the TBP model. This includes the residence times of water at the interface, where stronger water-TBP hydrogen bonding causes long-lived residences. Interestingly, there are a number of features that are relatively insensitive to the TBP hydrophilicity. In one important case, the concentration of water-bridged TBP dimers was only impacted by the least hydrophilic model. As these dimeric species are the building block of surface protrusions that lead to water transport across the interface, this implies that collective organizational patterns and surface structures that derive from multiple driving forces (e.g., TBP hydrophilicity and organic solvent free energies of solvation) are less sensitive to individual force field parameters. Further, we note that competitive interactions can “cancel” the effects of changing TBP charge on interfacial properties. One example is the orientation and hydrogen bonding structure of interfacial water, where the direct TBP-water hydrogen bonding competes against the indirect TBP-induced interfacial roughness. In combination, these observations may assist future simulation studies in calibrating surfactant models to, or interpreting results of, a broad range of dynamic, structural and thermodynamic properties.

Organophosphorus flame retardants in a typical freshwater food web: Bioaccumulation factors, tissue distribution, and trophic transfer

Water, sediment, and wild aquatic species were collected from an electronic waste (e-waste) polluted pond in South China. This study aimed to investigate the bioaccumulation, tissue distribution, and trophic transfer of organophosphorus flame retardants (PFRs) in these aquatic organisms. The concentrations of PFRs detected in the analyzed organisms were between 1.7 and 47 ng/g wet weight (ww). Oriental river prawn and snakehead exhibited the highest and lowest levels, respectively. Tri-n-butyl phosphate (TnBP), tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCPP) and triphenyl phosphate (TPhP) were dominant contaminants, accounting for approximately 86% of the total sum. The mean values of bioaccumulation factors (BCFs) and logarithmic biota-sediment accumulation factors (log BSAFs) for individual PFRs varied from 6.6 to 1109 and from −2.0 to 0.41, respectively. Both log BCFs and log BSAFs of PFRs were significantly and positively correlated with their octanol-water partitioning coefficient (log KOW). The concentrations of PFRs in tissues of large mud carp and snakehead were significantly and positively correlated with the lipid content (each p < 0.05) and the liver, kidney, and gill exhibited high PFR levels. When the concentration was expressed on a lipid basis, liver exhibited the lowest level, indicating the probable effects of metabolism. Significantly positive correlation was also found between lipid content and total PFR concentration in muscle of all aquatic organisms, given the strong correlation between lipid content and the concentration of TnBP. Trophic magnification factors (TMF) of TnBP and TPhP were lower than 1 (0.57 and 0.62), indicating that these PFRs undergo trophic dilution in this aquatic food web.

Carbon dioxide separation using α‐alumina ceramic tube supported cellulose triacetate‐tributyl phosphate composite membrane

AbstractCarbon dioxide emissions to the atmosphere lead to global warming and unpredictable climate change via the greenhouse effect. Carbon dioxide from industrial sources can be captured by the membrane separation technique to mitigate the greenhouse effect. In this research, a polymer solution was prepared by blending a cellulose triacetate (CTA) polymer with a tri‐n‐butyl phosphate (TBP) additive. The polymer solution was coated on an alumina (α‐Al2O3) tube, which acted as a support material, to prepare a composite membrane for the CO2 separation. The composite membrane that was prepared was characterized by Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermo‐gravimetric analysis (TGA), and differential scanning calorimetry (DSC) analyses. The CO2 permeance and the selectivity for the prepared composite membrane were evaluated using a constant pressure‐variable volume method. The influence of the concentration of CTA and TBP, polymer solution preparation time, number of sequential dip coating, and the feed gas pressure on the CO2, N2, and CH4 gas separation performances was examined. The highest CO2 permeance of 129 GPU and the selectivity of 19.9 versus N2 and 10.6 against CH4 were obtained for the pure gases, and a CO2 permeance of 116 GPU and selectivity of 17.1 against N2 were obtained for a mixture of gases (15% CO2/85% N2). © 2019 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Tissue-specific distribution and bioaccumulation potential of organophosphate flame retardants in crucian carp

The concentrations, distributions, and bioaccumulation of nine organophosphate flame retardants (OPFRs) were investigated in both abiotic and biotic media, comprising river water, sediment, and crucian carp. The highest concentrations were observed in liver (6.22–18.1 ng/g ww), and the levels in muscle (4.23–7.75 ng/g ww) and gonad (3.08–7.70 ng/g ww) were similar. In whole blood, tris(2-butoxyethyl) phosphate (TBOEP; 31.1–256 ng/mL) accounted for 90% of the total OPFR concentration. Distributions of OPFRs differed between biotic and abiotic media, as tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), and TBOEP were dominant in abiotic media, whereas triethyl phosphate (TEP), tri-n-butyl phosphate (TNBP), TCEP, and TBOEP dominated in crucian carp. The TNBP had remarkable accumulation potential among nine OPFRs, which the TNBP concentrations in muscle increased with increased total length and body weight. The higher perfusion rate of TNBP to female eggs were observed rather than to male gonads as the concentrations were higher in males than in females, while the opposite results were observed in gonad. Moreover, the concentration of TNBP in female muscle began to decrease near maximum growth as a sexually dimorphic difference in crucian carp. This is the first study to simultaneously investigate the fate of OPFRs in biotic and abiotic media and to show sex differences.

Application of Bulk Liquid Membrane Technique for Cadmium Extraction from Aqueous Solution

The extraction of cadmium from aqueous solution using kerosene as a bulk liquid membrane (BLM) with Tri-n-butyl phosphate (TBP) as a carrier was experimentally investigated under various operating conditions. The effects of feed and strip pH, feed initial concentration, TBP concentration, and strip to feed volume ratio on the cadmium ions transport efficiency were investigated. A stripping agent EDTA was used to enhance the transport efficiency of the cadmium ions. Flax and sesame oils were also considered as green liquid membrane alternatives to kerosene. They were evaluated in terms of extraction and separation efficiency. Cadmium extraction and stripping efficiencies of 89 and 94% were, respectively, obtained under specific conditions (100 ppm initial concentration of cadmium ions, 10% (v/v) TBP concentration, (1:2) strip to feed volume ratio, feed phase pH of 3, and strip phase pH of 11). The kinetics of $$\hbox {Cd}^{2+}$$ transport across BLM was investigated using kinetic model derived from the kinetic law of two consecutive irreversible first-order model. Both flax and sesame oils were found less efficient than kerosene in cadmium extraction and stripping rates.

Separation of phenylacetic acid using tri-n-butyl phosphate in hexanol: Equilibrium and kinetics

ABSTRACTEquilibrium and kinetics studies are required to design the continuous extraction process for the acid-extraction system. In the present study, an attempt has been made to investigate the equilibrium and kinetics parameters for the reactive extraction of phenylacetic acid (PAA) with tri-n-butyl phosphate (TBP) in hexanol. The equilibrium results show that the formation of the (1:1) PAA–TBP complex in the organic phase with an overall equilibrium complexation constant (Ke) was 78.74 and 29.15 m3.kmol−1 for TBP concentrations of 0.734 and 1.464 kmol.m−3, respectively. The mass transfer coefficients (kL) for PAA were found to be in the range of 3.7 × 10–5–6.2 × 10–5 m.s−1. Based on the Hatta number (Ha = 8.48), the reaction was found to be fast chemical reaction (regime 3) with the order of reaction as 0.77 and 0.36 with respect to PAA and TBP, respectively. The rate constant of the reaction was obtained as 0.017 kmol.m−3.s−1.

Studies on liquid–liquid extraction of La(III) from acidic nitrate medium using TBP in petrofin

The present study aims at investigating the capability of tri-n-butyl phosphate (TBP) in petrofin as extracting agent for La(III) from acidic nitrate medium. The concentrations of TBP and sodium nitrate have positive influence while temperature shows a negative impact on the extraction. The values of standard enthalpy change and entropy change confirm the extraction process as exothermic with a decrease in randomness due to complexation. Regression analysis results fit well with the experimental data in the cases of TBP and nitrate concentration variation.

Insight into acidity driven third phase formation of TBP in organic solutions by MD simulation

Abstract Nitric acid extraction by tri-n-butyl phosphate (TBP) in dodecane is investigated by molecular dynamics (MD) simulation, for different concentrations of TBP in the range 0.1 M to 2 M with aqueous phase HNO 3 concentration of 1 M, 2 M and 3 M. The MD studies are carried out considering dissociated as well as molecular forms of HNO 3 . The simulations showed formation of a third phase consisting of TBP, HNO 3 and water which is in agreement with reported experimental results. HNO 3 , in dissociated form, shows formation of NO 3 − and H 3 O + pockets in the third phase while HNO 3 in molecular form remains dispersed in the third phase without such specific formations. The impact of concentrations of the acid and TBP on the third phase formation, reverse micelles of TBP in dodecane and NO 3 − and H 3 O + pockets in the third phase, have been demonstrated. The estimated diffusion coefficient values of TBP and dodecane match well with the reported literature values.

A systematic research on solvent extraction process for extracting 233U from irradiated thorium

In consideration of the lack of systematic investigations on solvent extraction process and equipments for extracting 233U from irradiated thorium, an extraction process using TBP (Tri-n-butyl phosphate) as extractant was proposed, optimized and verified. First, the process parameters, including concentration of TBP and HNO3, phase ratio, are preliminary selected. Then, a multistage countercurrent extraction using batch simulation is used to further optimize the parameters. Finally, the extraction process is verified through the continuous multistage countercurrent extraction using both mixer settler and centrifugal extractor, and the process operation efficiency is estimated by equilibration time and concentration profiles of Th and U after equilibrium.

Quantifying Dimer and Trimer Formation by Tri-n-butyl Phosphates in n-Dodecane: Molecular Dynamics Simulations.

Tri-n-butyl phosphate (TBP), a representative of neutral organophosphorous ligands, is an important extractant used in the solvent extraction process for the recovery of uranium and plutonium from spent nuclear fuel. Microscopic pictures of TBP isomerism and its behavior in n-dodecane diluent were investigated utilizing MD simulations with previously optimized force field parameters for TBP and n-dodecane. Potential mean force (PMF) calculations on a single TBP molecule show seven probable TBP isomers. Radial distribution functions (RDFs) of TBP suggest the existence of TBP trimers at high TBP concentrations in addition to dimers. 2D PMF calculations were performed to determine the angle and distance criteria for TBP trimers. The dimerization and trimerization constants of TBP in n-dodecane were obtained and match our own experimental values using the FTIR technique. The new insights into the conformational behaviors of the TBP molecule as a monomer and as part of an aggregate could greatly aid in the understanding of the complexation between TBP and metal ions in a solvent extraction system.