TBP Concentration Research Articles

Comparison of dynamic tests of the modified purex process flowsheet using 30 and 45% TBF in isoparafin

Results of centrifugal contactor rig trials of the flowsheet of the first solvent extraction cycle in protective glove boxes using simulated solutions of spent nuclear fuel and 30 and 45% TBP in isoparaffin as a solvent are compared. It was shown that an increase in the TBP concentration to 45% resulted in deterioration of the quality of the products obtained by the same flowsheets with 30% TBP in Isopar L as a solvent. Comparison of experimental and computer simulated profiles of component distribution across the stages of extraction units demonstrated satisfactory agreement in nitric acid and uranium concentrations. At the same time, it was found that simulation model of zirconium, technetium, and neptunium extraction requires improvement considering interaction of these elements with complexing agents.

Selective lithium recovery from lithium precipitation mother liquor by using a diketone-based solvent

Selective lithium recovery from lithium precipitation mother liquor by using a diketone-based solvent

Recovery of uranium from phosphate ore of Iran mine: Part II- solvent extraction of uranium from wet-process phosphoric acid

Recovery of uranium from phosphate ore of Iran mine: Part II- solvent extraction of uranium from wet-process phosphoric acid

Substantiation of the Practical Feasibility of the Modified Scheme of Purex Process with an Increased TBP Concentration Using Mathematical Modeling

Substantiation of the Practical Feasibility of the Modified Scheme of Purex Process with an Increased TBP Concentration Using Mathematical Modeling

Introduction and calculation of interaction coefficients in solvent extraction of rhenium from molybdenite

• Introduction of interaction effect and calculation of interaction coefficients of extraction parameters (pH, TBP concentration and O/A phase ratio) in solvent extraction of rhenium from molybdenite concentrate leach liquor in two states was performed: - dependent state (parameters are dependent to each other) independent state (parameters are independent from each other). • Equation of extraction efficiency was calculated in both of mentioned states. • Stripping of Mo and Re was studied and reported. In this research, a new concept called interaction coefficient in solvent extraction was introduced. Among effective parameters on rhenium extraction, organic phase to aqueous phase ratio, TBP concentration, and pH were selected as main parameters. Experiments were designed according to Response Surface Method using Minitab software. Rhenium and molybdenum concentrations were measured using Atomic Absorption Spectrometry. Rhenium’s maximum extraction was 93.8 % at pH = 0.5, [TBP] = 2.54 mol/L and, organic to aqueous phase ratio of 2:1, and molybdenum extraction under these conditions was nearly 40 % on average. The results obtained from experiments using Minitab software showed that there is a dependence between pH, O/A phase ratio and TBP concentration. For example, the related equations for the recovery percent relation to TBP concentration in the independent state is equal to ∂ R ∂ T B P = A + 0.31 ( T B P ) and in the dependent state is equal to ∂ R ∂ T B P = 2.7960 + 0.31 T B P C + C ′ T B P .

A quantum-chemistry and molecular-dynamics study of non-covalent interactions between tri-n-butyl phosphate and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

• A multiscale approach for evaluating interactions between extractant and ionic liquids was proposed. • Good agreements between MD simulations and experimental data on the physical properties of the extractant/ILs mixture. • Different local structures were observed at different extractant concentration. The complicated behavior of extractants in ionic liquids (ILs) has posed great challenges for radionuclides separation and purification. In this regard, a theoretical investigation of combining quantum chemical (QC) calculations and molecular dynamics (MD) simulations was performed to explore the local structures, intermolecular interactions, and dynamic behaviors between the tri- n -butyl phosphate (TBP) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C 4 mimTf 2 N) system. It is demonstrated that the ion pair of C 4 mimTf 2 N rather than the separated ions is more favored either in the gas phase or in solution. Their interaction with TBP is primarily dominated by the electrostatic interaction in most cases, while the dispersion and induction ones are non-negligible. Simultaneously, the intermolecular changes the atom charges of TBP and C 4 mimTf 2 N. Similar local structures have been accessible by both QC and MD calculations. It is revealed that the local structures and intermolecular interactions are strongly dependent on the TBP concentration.

Synergistic interaction between organophosphorus extractants for facilitated lanthanum transport through supported liquid membrane

The development of the membrane process is an effective strategy that increases the efficiency of separation processes. Extraction of lanthanum in the category of rare earth elements with the supported liquid membrane was examined in a laboratory system by studying the synergistic effects of organophosphorus extractants. The experimental design technique (CCD approach) was used in two steps to optimize the results. In the first step, the concentrations of the organophosphorus extractants (mixtures of D2EHPA, TBP and TOPO), and in the second step, secondary parameters such as the amount of ions present in the aqueous solution, the acidity concentration of feed phase and stripping solution were optimized to reach the maximum permeability coefficient through the membrane. The optimum conditions for TOPO, TBP, and D2EHPA extractant concentration, pH of the feed solution, La(III) ion concentration, and HNO 3 stripping phase were obtained equal to 0.1 M, 0.3 M, 0.8 M, 5.2, 200 ppm, and 2 M, respectively. The extraction and stripping efficiencies in optimum condition are obtained equal to 56.89, and 49.88%, respectively. The correlation coefficient equal to 0.96 and 0.94 in both steps showed the validity of models to predict permeability coefficient for lanthanum extraction. • Supported liquid membrane is an appropriate method for extraction of lanthanum. • Important parameters were optimized with the central composite design method. • New Synergistic trend was observed in the addition of extractant in the SLM. • Antagonistic trend was appeared in the addition of TOPO to D2EHPA extractant. • Positive effects were observed in the increase of pH of the feed solution.

Experimental and CFD scale-up studies for intensified actinide/lanthanide separations

• Selective separations of U(VI)/Er(III) in HNO 3 by TBP/D80 in small-scale reactors. • Evaluation of mixing zone on the extraction performance of the small-scale reactor. • CFD model to simulate reactor’s extraction performance using one experimental point. • Hydrodynamic parameters affecting mass transfer performance of small-scale reactors. In this paper, systematic studies are performed to identify the parameters that influence the selective separation of actinides from a mixture with lanthanides in small channels. In particular, the separation of dioxouranium metal ions (UO 2 +2 ) from a binary U(VI)/Er(III) mixture in a nitric acid solution by an organic TBP/kerosene (Exxsol D80) phase, relevant to spent nuclear fuel reprocessing is investigated. The effects of parameters such as TBP concentration, organic-to-aqueous phase flow rate ratio, channel size, and residence time on mass transfer are evaluated, whilst the mass transfer performance in the extraction channels is further analysed using two important hydrodynamic features, i.e. plug formation time and interfacial area to volume ratio. Circular channels with diameters from 1 to 3 mm are used to investigate the effect of scale on the mass transfer characteristics. The importance of the mixing zone on mass transfer is also evaluated. A CFD model is proposed to simulate the mass transfer during plug flow. Using only one experimental point, once the plug has been formed, the model is able to predict extraction percentage with less than 4% difference compared to the experiments.

Stability-improved perovskite solar cells through 4-tertbutylpyridine surface-passivated perovskite layer fabricated in ambient air

Methylammonium lead iodide (CH3NH3PbI3) perovskite solar cell (PSC) is one of the third generations of photovoltaic (PV) research interest in recent years. The solar cell degrades very fast in ambient air and this poses major challenge for its commercialization. Hence, this report investigates surface-passivated perovskite layer using hydrophobic material, 4-tertbutylpyridine (tBP), to modify the surface of the perovskite layer and create ambient air-resistant layer that results in improved stability of PSC performance. The fabricated films and devices were studied using UV–Vis spectrophotometer, Fourier-transform infrared (FTIR) spectrometer, Scanning Electron Microscopy (SEM), solar simulator equipped with Keithley source meter and X-ray diffractometer (XRD). The concentration of tBP was varied from 50 to 200 μl and the samples were aged in ambient air for 120 h. Eventually, the surface passivated film and the device showed improved stability performance. The champion cells of tBP-treated and untreated freshly fabricated devices showed PCE of 10.32% and 6.37%, respectively. Again, the PCE of tBP-treated and untreated devices reduced by 6.45% (10.32%–9.66%) and 60.75% (6.37%–2.50%) respectively for 120 h. Additionally, continuous light-soaking for 8 h shows that tBP-treated device is stable in its performance when compare with the tBP-untreated device. The statistical analyses carried out showed that device PCE stability depended mainly on the device tBP treatment. Also, device treatment varies directly proportional to the PCE. The probability plot from the statistical analysis also showed that observed (experimental) data agreed with predicted data. Consequently, this work implies that ambient stability of perovskite solar cell can be achieved from surface-passivation of perovskite layer for commercialization of the PSCs.

Proficiency of tellurium extraction in pulsed disc and doughnut columns

ABSTRACT In this research, the separation of tellurium from selenium was studied from chloride solution by TBP extractant. In the batch experiments, the experimental findings indicated that the feed acidity, TBP concentration, and contact time were optimized to achieve the high separation factor. In continuous mode of pulsed disc and doughnut column, the impacts of operating parameters have been discussed on the distribution coefficients of selenium and tellurium, and mass transfer enhancement. A new model for predicting Koca was proposed in terms of holdup values, Sherwood, Reynolds, and Schmidt numbers, which has an acceptable agreement with the mass transfer data.

Lithium extraction from aqueous solution using different metal chloride as co-extraction reagent

Abstract Selectivity lithium extraction from aqueous solution using different metal chloride as co-extractant was investigated. The mainly factors, molar ratio of M/Li, Phase ratio O/A, concentration of TBP and the extraction time were studied, the results showed the ability of lithium extraction using MClx as co-extraction reagent in single-stage extraction was: MnCl2 > CuCl2 > ZnCl2 > CoCl2 > NiCl2 > CrCl3; While in the three-stage extraction, the sequence was: MnCl2 > ZnCl2 > CuCl2 > CoCl2 > CrCl3 > NiCl2. FT-IR investigation was carried out to identify the inner structure of extracted complexes. The slope analysis was used to determine the stoichiometry of the extracted complex. To further identify the composition of the extracted complexes, saturation capacity method was conducted to deduce the complex.

Application of Unified Model with TBP Dilution to Description of Extraction of Nitrates of Tetravalent Zirconium and Hafnium Actinides from Nitrate Solutions

Published and authors’ own data have been used to create a unified mathematical model describing the distribution of uranyl nitrate, nitric acid, and tetravalent elements in TBP with consideration for its dilution in their distribution in neutral and acid systems in a wide range of component concentrations. As the base values of the concentration equilibrium constants were taken their values calculated for pure TBP. In this case, raising the diluent concentration leads to a linear dependence of the logarithms of the extraction constants on the TBP concentration with a parameter a the value of which reflects the influence exerted by the nature of a diluent. It is assumed that, simultaneously, there occur several complexation reactions in the aqueous and organic phases and a nonstoichiometric physicochemical interaction of the components. The values of the equilibrium constants of the extraction reactions and the corresponding parameters a were determined for tetravalent thorium, uranium, plutonium, neptunium, zirconium, and hafnium, which made it possible to describe their extraction with TBP solutions in a hydrocarbon diluent at concentration of the extractive agent of 5 to 100 vol %. The error in calculations of the distribution coefficients in terms of the model does not exceed 12%.

Removal of antibiotic tetracycline using nano-fluid emulsion liquid membrane: Breakage, extraction and stripping studies

Abstract In this study, nano-fluid emulsion liquid membrane (NFELM) was used to extract tetracycline (TC) from simulated wastewater. The membrane phase comprises of n-heptane (diluent), Fe2O3 nanoparticles modified with oleic acid (stabilizing agent), and tri-butyl-phosphate (TBP, extractant) homogenized with hydrochloric acid (HCl) as the internal aqueous phase to create the nano-fluid emulsion. The effect of various experimental parameters, such as emulsification speeds and times, internal/membrane volume ratio, nanoparticles dosage, HCl and TBP concentration, and external phase pH were investigated to determine emulsion stability, extraction and stripping efficiency. More than 97 % of TC was effectively extracted by NFELM system at 12 min mixing time without significant emulsion breakage, and the stripping efficiency was 96.5 %. NFELM proved to be more stable, efficient, and has higher mass transfer coefficient of 7.344 × 10−9 (m/s) than traditional ELM of 5.82 × 10−9 (m/s). The membrane material and nanoparticles were successfully recycled five times in this work for the extraction of TC.

Use of a Unified Model with TBP Dilution for Describing the Extraction of Nitric Acid and Hexavalent Actinide Nitrates in Multicomponent Nitrate Systems

A unified model based on published data and authors’ experimental results was suggested for describing the extraction of An(VI) (An = U, Np, Pu, Am) from HNO3 solutions into TBP solutions of various concentrations. Parallel occurrence of several extraction reactions and of nonstoichiometric physicochemical interaction of the components is assumed. The calculated parameters of the dependence of the concentration equilibrium constants on the total TBP concentration allowed expansion of the range of extractant concentrations described by the model (from 2.7 to 100%) and reduction of the uncertainty in calculation of the HNO3 and An(VI) distribution ratios. The parameter of apparent hydration of nitrate salt cations in the aqueous phase was used for describing the salting-out effect of these salts.

Stability of the oxidized form of RuLL′(NCS)2 dyes in acetonitrile in the presence of water and pyridines – Why the dye-sensitized solar cell electrolyte should be dry

Abstract The detrimental effect of electrolyte water contamination on the light-soaking lifetime of Dye-sensitized Solar Cells (DSCs) prepared with RuLL′(NCS)2 dyes and N-additives like 4-tert-butylpyridine (TBP) is not well understood. A new explanation is presented based on investigation of the stability of the ruthenium(III) complexes Ru(bipy)2(NCS)2+ (1+) and RuLL′(NCS)2+ (L = 4,4′-dicarboxy-2,2′-bipyridine, L′= 4,4′-nonyl-2,2′-bipyridine) (Z907+) in acetonitrile in the presence of water and pyridines covering a large variation in basicity. 1+ reacts with small amounts of water in the acetonitrile containing a pyridine base (X) according to the overall reaction: 6Ru(bipy)2(NCS)2+ + 4H2O + 8X → 5Ru(bipy)2(NCS)2 + Ru(bipy)2(NCS)(CN) + SO42− + 8XH+. The reaction mechanism of 1+ (and Z907+) is proposed to be initiated by an attack of OH− giving Ru(bipy)2(NCS)(NCS-OH). The stronger the base the faster the reaction. Extrapolating the life time of Z907+ to a typical TBP concentration of 0.5 M in the DSC gives a degradation rate around 7 s−1. Z907+ bound to a layer of nano crystalline TiO2 surface reacted fast too, when inserted in an acetonitrile solution containing 4-tert-butylpyridine. In a “wet” electrolyte, containing more than 500 mM of water the light-soaking lifetime of a DSC prepared with Z907 is predicted to be about 10 days at out-door light soaking conditions, whereas trace amounts of water (

Experimental Study on Reactive Extraction of Malonic Acid with Validation by Fourier Transform Infrared Spectroscopy

Malonic acid is an essential carboxylic acid that is used as a backbone reactant in deriving multiple higher-order carboxylic compounds. The successful attempt of producing malonic acid from a biological route has attracted the scientific community to extract malonic acid from a fermentation broth or dilute aqueous stream. Experimental study on the recovery of malonic acid by reactive extraction was performed, and the effects of TBP concentration, diluents (alkane, ketone, and alcohol), and malonic acid concentration were investigated. The equilibrium models (relative basicity and mass action law models) and the number of theoretical units (NTU) were also evaluated. Fourier transform infrared spectroscopy provided evidence for the formation of significant bonds among extractant–diluent–acid complexation systems which support the experimental outcomes. The results of extraction equilibrium are discussed regarding dimerization constant (DMA), partition coefficient (PMA), extraction efficiency (EMA%), distri...

Intensification of zirconium and hafnium separation through the hollow fiber renewal liquid membrane technique using synergistic mixture of TBP and Cyanex-272 as extractant

Abstract The novel synergistic mixture of TBP and Cyanex-272 is used as the extractant in the hollow fiber renewal liquid membrane (HFRLM) technique for Zr/Hf separation. The effects of the chemical and operational parameters such as HNO3 concentration in the donor phase, NH4F concentration in the acceptor phase, Cyanex-272 and TBP concentration in the liquid membrane phase, the lumen and shell side flow rates, and aqueous/organic volume ratio on the mass transfer and separation performance of HFRLM method were investigated. The obtained results reveal the intensification potential of proposed HFRLM technique for selective extraction of Zr over Hf with separation factor higher than 100. The HFRLM method provides two times higher mass transfer flux in comparison with hollow fiber supported liquid membrane (HFSLM). Also, the HFRLM method shows satisfactory stability for 700 min of continuous operation. The Zr ion transport through the LM phase follows the coupled co-transport mechanism and the diffusion in the renewal layer is recognized as the rate-controlling step in the HFRLM process. Moreover, the Zr mass transfer coefficient and molar flux in the HFRLM method are calculated in the range of 1 × 10−8 to 8.4 × 10−7 m·s−1 and 4.9 × 10−6 to 20.1 × 10−6 mol·m−2·s−1, respectively.

Lithium extraction from low-grade salt lake brine with ultrahigh Mg/Li ratio using TBP – kerosene – FeCl3 system

A novel Li+ extraction process from low - grade salt lake brine with ultrahigh Mg/Li mass ratio was investigated using TBP - kerosene - FeCl3 system in this work. The effects of various factors (such as TBP concentration, Fe/Li molar ratio and acidity of brine) on Li+ extraction was first studied, and the optimum conditions of single - stage extraction was identified as follows: TBP concertation was 75%, Fe/Li molar ratio was 1.3, and the acidity of brine was 0.01 mol/L. The extraction efficiency of Li+ and separation factor of Li/Mg in single - stage reached 67.9% and 435.5 respectively. The extraction, scrubbing, stripping and regeneration processes were studied respectively to optimize the operation conditions of each section, and a novel reflux scrubbing process was put forward. Then an eleven –stage whole extraction process experiment was carried out at the optimum conditions. The capacity of Li in organic phase reached 2.0 g/L. The extraction efficiency of Li+ reached 87.9%, and stripping liquor containing 28.83 g/L Li+ and 0.617 g/L Mg2+ was obtained. The Mg/Li mass ratio changed from 370 in salt lake brine to 0.02 in the stripping liquor. The aims of separation, purification and enrichment Li+ were achieved concurrently through the novel extraction process without any other additional process.

Spatial analysis of toxic or otherwise bioactive cyanobacterial peptides in Green Bay, Lake Michigan.

Cyanobacterial harmful algal blooms (cyanoHABs) are a growing problem in freshwater systems worldwide. CyanoHABs are well documented in Green Bay, Lake Michigan but little is known about cyanoHAB toxicity. This study characterized the diversity and spatial distribution of toxic or otherwise bioactive cyanobacterial peptides (TBPs) in Green Bay. Samples were collected in 2014 and 2015 during three cruises at sites spanning the mouth of the Fox River north to Chambers Island. Nineteen TBPs were analyzed including 11 microcystin (MC) variants, nodularin, three anabaenopeptins, three cyanopeptolins and microginin-690. Of the 19 TBPs, 12 were detected in at least one sample, and 94% of samples had detectable TBPs. The most prevalent TBPs were MCRR and MCLR, present in 94% and 65% of samples. The mean concentration of all TBPs was highest in the Fox River and lower bay, however, the maximum concentration of all TBPs occurred in the same sample north of the lower bay. MCs were positively correlated with chlorophyll and negatively correlated with distance to the Fox River in all cruises along a well-established south-to-north trophic gradient in Green Bay. The mean concentration of MC in the lower bay across all cruises was 3.0 +/- 2.3 μg/L. Cyanopeptolins and anabaenopeptins did not trend with the south-north trophic gradient or varied by cruise suggesting their occurrence is driven by different environmental factors. Results from this study provides evidence that trends in TBP concentration differ by congener type over a trophic gradient.

Scandium Extraction from Chloride Solutions by a Mixture of Tributyl Phosphate and Molecular Iodine

It has been established that the addition of elemental iodine significantly enhances the extraction of scandium by means of tributylphosphate. The metal distribution coefficients exhibit an increase with increasing TBP and iodine concentration in the organic phase as well as with increasing chloride ion concentration in the aqueous phase. As an outsalting agent, chlorides of alkali, alkaline earth and other weakly extracted metal cations can be used. The process is promising for the extraction of scandium from solutions of hydrochloric- acid leaching of mineral and man-made materials.