Tributyl Phosphate Solutions Research Articles

Removal of TBP sorbed on wood by Trametes versicolor through solid-state fermentation

The use of white-rot fungi is a promising approach for removing organophosphate flame retardants (OPFRs) from wastewaters. Immobilization in wood for this purpose ensures the predominance of the fungus but also contributes to OPFRs sorption. This work focused on the ability of T. versicolor to degrade tributyl phosphate (TBP) sorbed in wood. This initially underwent ten sorption cycles, each involving exposure to a 10mg · L-1 TBP solution. Throughout each cycle, the wood exhibited a sustained sorption capacity (0.035 ± 0.002mg TBP · g. dry wood-1 per cycle). The wood residues obtained after each sorption cycle were inoculated with T. versicolor. After 60 days of inoculation, fungus degraded over 90% of TBP in each cycle’s wood residue. However, fungal growth was inhibited, resulting in a 43% decrease in biomass compared to controls. The fact that biomass remained active and capable of degrading TBP suggests that the growth decrease is likely due to the formation of transformation products. An increase in toxicity units (from 13.64 to 87.86 at the end) was associated with the accumulation of 3-hydroxybutyl dihydrogen phosphate (OH-MBP). However, subsequent experiments demonstrated that given sufficient time, the fungus not only degraded OH-MBP but also produced a non-toxic effluent.

Radiation-induced effects during the extraction of Pu-239 nitrate with a solution of tributyl phosphate in octafluoropentanol formal

Radiation-induced effects during the extraction of Pu-239 nitrate with a solution of tributyl phosphate in octafluoropentanol formal

Study of degrading a tributyl phosphate solution via a plasma-based advanced oxidation process using a submerged multi-hole dielectric barrier discharge

Study of degrading a tributyl phosphate solution via a plasma-based advanced oxidation process using a submerged multi-hole dielectric barrier discharge

Protective Effects in the Radiolysis of Acidified Hydrocarbon Solutions of Tributyl Phosphate

Protective Effects in the Radiolysis of Acidified Hydrocarbon Solutions of Tributyl Phosphate

Kinetics and mechanism of Eu(III) transfer in tributyl phosphate microdroplet/HNO3 aqueous solution system revealed by fluorescence microspectroscopy.

In this study, we reveal an Eu(III) extraction mechanism at the interface between HNO3 and tributyl phosphate (TBP) solutions using fluorescence microspectroscopy. The mass transfer rate constant at the interface is obtained from the analysis of fluorescence intensity changes during the forward and backward extractions at various HNO3 and TBP concentrations to investigate the reaction mechanism. This result indicates that one nitrate ion reacts with Eu(III) at the interface, whereas TBP molecules are not involved in the interfacial reaction, which is different from the results obtained using the NaNO3 solution in our previous study. We demonstrate that the chemical species of Eu(III) complex with nitrate ion and TBP in the aqueous solution play an important role for the extraction mechanism. The rate constants of the interfacial reactions in the forward and backward extractions are (4.0-5.0) × 10-7mM-1s-1 and (3.2-3.3) × 10-6ms-1, respectively. We expect that our revealed mechanism provides useful and fundamental knowledge for actual solvent extraction.

3D printed field-deployable microfluidic systems for the separation and assay of Pu in nuclear forensics.

A compact field-deployable microfluidic system has been developed to improve timelines for the rapid analysis of debris in post-detonation nuclear forensics. We used a high-resolution 3D printer to miniaturize typical laboratory-based procedures into a fieldable platform. Microfluidic half-modules were produced for the purification of Pu from excess U, along with a portable alpha chamber for the following isotopic analysis of the Pu stream. A porous PTFE membrane is soaked with a hydrophobic tributyl phosphate (TBP) solution and is placed between two half-modules; separation is performed as a liquid-liquid extraction in an extraction channel across this membrane, where the forward and back-extractions occur within one complete module. Following separation, a 100 μL sampling of the Pu-bearing stream is injected into a small-footprint 3D printed alpha chamber for isotopic assay via alpha spectrometry as part of an online process. In this first demonstration of microfluidic separation coupled with online alpha spectrometry, high extraction yields have been obtained for Pu (98.9 ± 4.0)% and U (97.5 ± 2.5)%. The process uses less than 800 μL of solution with separation chemistry complete within 45 minutes and subsequent alpha spectrometry initiating 25 minutes after separation.

Recovery of niobium during comprehensive processing of pyrochlore-monazite-goethite ores

This paper looks at the pyrochlore-monazite-goethite ores of the Chuktukonsk deposit (0.98wt.% Nb2O5) and their processing with the help of acidbased (HNO3, H2SO4) and sulphatization techniques. Nitric-acid pressure leaching was found to be an efficient processing technique for this type of ore: ore size –0.074 mm; CHNO3 = 25%; CH2O2 = 5%; τ = 2 h; solid-to-liquid = 1:9; heat treatment mode: 1 h at 160 oC followed by 1 h at 230 oC. As a result, rare earth metals and manganese are leached to the solution while all of the contained niobium remains in the cake. Two different techniques were tested to recover niobium from the cake. One is based on the use of alkali (NaOH sintering), the other is an extractive leaching technique that combines acid leaching with liquid-liquid extraction of tributyl phosphate in one stage. It was established that niobium mi nerals can be efficiently decomposed when using a mixture of hydro fluoric and sulphuric acids with the concentrations of 4.08 and 8.46 mol/L, correspon dingly, as a leaching agent. At the weight ratio of 1:2:1 of the solid to aqueous to organic phase and after the slurry has been stirred intensively for 5 minutes, niobium fluorides, which form as a result of interaction between hydrofluoric acid and the cake components, can be recovered with a 50% solution of tributyl phosphate in octane. After that they transfer to an organic phase while impurities get accumulated in the solid residue. As niobium-containing cake has a high concentration of silicon, it is recommended to first remove silicon from the cake using a strong alkaline solution.

La(III) Ion Selective Electrode with PTFE Membrane Containing Tributyl Phosphate Ionophore

Methods for the quantitative determination of lanthanum that have been developed are generally spectroscopic methods such as inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES), and X-ray fluorescence spectrometry, which has relatively high operational costs. The feasibility of the potentiometric method using ion selective electrode (ISE) as an alternative method for lanthanum (III) determination needs to be studied because it is simple, easy to use, and has high sensitivity and selectivity. In this study, we developed ion selective electrode using PTFE membrane impregnated with tributyl phosphate (TBP) as ionophore. TBP is commonly used as a complexing agent for rare-earth ions in supported liquid membrane (SLM) separation process. We found that the compound can be used as an ionophore for ISE. This study aims to make a lanthanum ion selective electrode (III) (La-ISE) which has a Nernstian response. The parameters studied in the construction of this electrode were the effects of PTFE membrane immersion ionophore solution, ionic strength adjuster (ISA), and the inner solution composition. The performance parameters studied for the La-ISE were linear range, response time, detection limit, selectivity, and the lifetime of the electrode. Construction of the electrode begins with the preparation of the PTFE membrane as the main component. PTFE membrane was impregnated for 12 hours in the TBP solution having a concentration of 0.25 M or 0.50 M in kerosene. After it was dried, the membrane was attached to the end of the electrode tube with adhesive. Then, the electrode was filled with an internal solution containing a mixture of KCl 10-3 M with La (III) 10-3 M. The internal reference electrode was Ag/AgCl electrode. Before it was used, the electrode was soaked in a solution of La (III) 10-3 M for 12 hours.The effect of TBP concentration on the electrode performance was studied using two concentrations of TBP: 0.25 M and 0.50 M. The calibration curves obtained using both electrodes have good linearity. Nernst factor obtained from both electrodes is similar, although the Nernst factor obtained with an electrode having 0.50 M TBP closer to the theoretical value.ISA used in the measurement was KNO3. The effect of ISA on the performance of the electrode was studied using electrodes containing TBP with the concentration of 0.25 M or 0.50 M. The concentration of KNO3 used in this study was 0.01 M and 0.10 M. The Nernst factors obtained with electrodes containing 0.25 M TBP, in general, higher than those obtained with electrodes containing 0.50 M TBP in the same ISA. Electrode containing 0.50 M TBP resulted in the Nernst factor close to theoretical value when a measurement was conducted in 0.10 M KNO3.

Extraction of Actinides with Tributyl Phosphate in Carbonates of Fluorinated Alcohols

ABSTRACT New non-inflammable compounds – carbonates of fluorinated alcohols were proposed as potential diluents for tributyl phosphate (TBP). These compounds are commercially available, have high boiling point, high density, and low solubility in water solutions. Extraction of actinides from nitric acid by TBP solutions in fluorinated carbonates was studied. TBP solutions in fluorinated carbonates show lower extraction ability comparing with TBP solutions in hydrocarbon diluents. In spite of this, it is possible to extract more than 99.9% of tetra- and hexavalent actinides presented in spent nuclear fuel solutions. The advantage of proposed solvent is possibility to obtain uranium strip product with uranium concentration higher than 100 g/l.

Description of the Extraction of Rare Earth Element Nitrates from Weakly Acidic Solutions with Concentrated Tributyl Phosphate Solutions

A mathematical model based on the published data was developed for the extraction of REE (from La to Lu, including also Y) nitrates in a wide concentration range in weakly acidic ([H+] ≪ [REE]) systems with TBP, taking into account the dilution of TBP with paraffins and including systems with salting-out agents. Parallel occurrence of several complexation reactions in the aqueous and organic phases and of nonstoichiometric physicochemical interaction of the components is assumed. The formation of REE trisolvate, tetrasolvate, and hydrate solvate, the coextraction of cerium- and yttrtium-group REEs in the form of an ion pair, and the self-salting-out effect caused by the apparent hydration of Ln3+ in the aqueous phase are taken into account. The model considers the effect of ammonium, sodium, and aluminum nitrates as salting-out agents. The influence of temperature on the REE extraction in these systems is also described. The error of calculating the distribution ratios is ≤10%.

Gold extraction from biosolid sludge obtained by sewage treatment

ABSTRACTTreatment of municipal wastewater, which involves multiple steps, produces large amounts of biosolid sludge, which is either incinerated or disposed in landfills. This sludge contains carbon, nitrogen, and phosphorous in appreciable amounts, and hence, it is being recently suggested that it should be used as a fertilizer. However, the biosolid sludge also contains large amounts of heavy metals, which exert harmful effects on the plantation and therefore, they must be removed before it can be used as a fertilizer. In addition, some of these heavy metals are precious such as gold. In this work, heavy metals present in the biosolid sludge produced from municipal wastewater plants were extracted using acidic solutions of different strengths. The method of selected gold extraction using tributyl phosphate (TBP) in kerosene solution from the metal rich acidic solution was also tested. The rate and yield of gold extraction increase with the increase in the acidic strength. The highest extracted gold yield was 0.012 mg/g of biomass. The amount of gold recovery into the TBP solution was 26%, which was much higher than that of other metals extracted into the acid solution. The importance of removing the metals from the biosolid is obvious, as it allows the latter to be used as a fertilizer. In addition, using only one additional step, a valuable product, gold, can be selectively separated, despite being present in lower amounts that other metals found in the sludge.

Kinetics of interphase transfer of zirconium between nitric acid and tributyl phosphate solutions

The study on the extraction kinetics of zirconium into the binary mixture of tributyl phosphate TBP and n-dodecane has been described in the present investigation. Experiments were carried in a constant interfacial area stirred cell. The effect of different parameters like stirring speed, temperature, specific interfacial area and concentrations of reactants and nitric acid on the extraction rate of zirconium were studied. A systematic approach has been adopted to determine location of reaction plane, kinetic regime and rate parameters. Based on the results of the present study, it is concluded that extraction reaction is interfacial and the overall extraction rate is controlled by chemical reaction between reactant molecules.

The structure of tributyl phosphate solutions: Nitric acid, uranium (VI), and zirconium (IV)

Diffusion, rheology, and small angle neutron scattering (SANS) data for organic phase 30 v/v % tributyl phosphate (TBP) samples containing varying amounts of water, nitric acid, and uranium or zirconium nitrate were interpreted from a colloidal perspective to give information on the types of structures formed by TBP under different conditions. Taken as a whole, the results of the different analyses were contradictory, suggesting that these samples should be treated as molecular solutions rather than colloids. This conclusion is supported by molecular dynamics (MD) simulations showing the existence of small, molecular aggregates in TBP samples containing water and nitric acid. Interpretation of TBP and nitric acid diffusion measurements from a molecular perspective suggest that nitric acid and metal species formed are consistent with the stoichiometric solvates that have traditionally been considered to exist in solution.

Gamma Radiation Thermal Stability of Two-Phase Mixtures of Nitric Acid with Degraded TBP in a Closed Vessel

The influence of thermal and gamma radiation effects on the characteristics of the thermal explosion of mixtures of tributyl phosphate (TBP) and nitric acid was studied. The products of sequential radiolysis and pyrolysis of TBP were determined to have little effect on the thermal stability of mixtures of TBP and nitric acid. The onset temperatures of exothermic processes leading to a thermal explosion were slightly decreased only by the absorbed dose of 2 MGy. The thermal stabilities of solutions of TBP in n-dodecane and diluent C-13, consisting of a mixture of saturated hydrocarbons, were investigated. The experimental results indicate that the irradiation decreased the onset temperature of the exothermic processes in mixtures of nitric acid with TBP solutions in a hydrocarbon diluent; the onset temperature decreased by 5°C to 7°C for n-dodecane and by 9°C to 13°C for C-13, as compared to unirradiated extractants.

Influence of carbon content, particle size, and partial manganese substitution on the electrochemical performance of LiFexMn1-xPO4/carbon composites

LiFePO4/C and LiFexMn1-xPO4/C (x = 0.7) nanocomposites were successfully synthesized via scalable spray-flame synthesis followed by solid-state reaction. A solution of iron (III) acetylacetonate and tributyl phosphate in toluene was used to produce amorphous, nanosized FePO4⋅H2O in a spray-flame reactor which was then milled with Li2CO3 and glucose to produce a LiFePO4/C composite material in a solid-state reaction. The influence of calcination temperature and carbon content on the properties of the resulting material was investigated using specific surface area measurements (BET), X-ray diffraction (XRD), electron microscopy, and electrochemical characterization. The impact of manganese addition on the electrochemical behavior was analyzed using cyclic voltammetry (CV) and constant-current (CC) measurements. XRD shows that the combination of gas-phase synthesis and subsequent solid-state reaction yields highly pure LiFePO4/C. BET measurement revealed that the particle size of LiFePO4 in the composite depends on the amount of glucose. A discharge capacity of more than 140 mAh/g at C/20 is achieved for LiFePO4/C with a carbon content of 6 wt%. This material supports high charge as well as discharge rates delivering more than 60 mAh/g at 16 C and sustains good cycle stability providing 115 mAh/g at 1 C. The energy density of the olivine increases about 10 % by substituting 30 mol% of iron by manganese while preserving the electrochemical performance of pure LiFePO4/C.

Calculation and Optimization of Plasma-Based Utilization Process of Inflammable Wastes after Reprocessing of Spent Nuclear Fuel of Closed Nuclear Cycle

This work demonstrates the results of modeling the joint utilization process of the spent solutions of tributylphosphate with hexachlorinebutadiene for extracting uranium and plutonium from a nitric acid solution of spent nuclear fuel and its processing wastes. Calculations are made for a wide range of temperature and mass fractions of air plasma coolant. Also, optimal inflammable water-organic compositions and work regimes for the practical implementation of this process in air plasma were determined.

Radiolysis of Tributyl Phosphate by Particles of High Linear Energy Transfer

Tributyl Phosphate (TBP), used in chemical separation processes for used nuclear fuel, is susceptible to radiolysis causing losses in process performance. We have studied its degradation by exposing dry 1M TBP/n-dodecane solutions to gamma radiation from a cesium-137 source and in a mix of low and high linear energy transfer (LET) radiation by irradiating samples in the UC Irvine TRIGA® reactor and utilizing the 10B(n,α)7Li reaction. In a 1 M solution of TBP in n-dodecane the degradation of TBP (G−TBP) was found to be 0.36 and 0.14 μmol/J for low and high LET radiation, respectively. The formation of dibutyl phosphoric acid, DBP, (G+DBP) in this solution was found to be 0.18 and 0.047 μmol/J for low and high LET radiation, respectively. In samples exposed to low LET as well as a mix of low and high LET a variety of TBP degradation products containing phosphorus were observed indicating that other degradation products than DBP and the monobutyl diacid (MBP) were formed. Our results for both low and high LET radiation compare well with previous studies on these systems indicating that high LET degrades TBP to a lesser extent than gamma radiation. Available data for high LET is not as abundant as for low LET making such comparisons challenging. Nevertheless, our method yields a value for G+DBP that agrees well with previous alpha radiolysis studies indicating that our method shows promise for studying high LET radiolysis in liquid-liquid extraction systems.

An Insight into Third-Phase Formation during the Extraction of Thorium Nitrate: Evidence for Aggregate Formation from Small-Angle Neutron Scattering and Validation by Computational Studies

Small-angle neutron scattering (SANS) studies were carried out to compare the aggregation behavior of 1.1 M solutions of tributyl phosphate (TBP) and N,N-dihexyl octanamide (DHOA) dissolved in different deuterated diluents, viz., n-dodecane, chloroform, and benzene, during the extraction of Th(IV) from nitric acid medium. The scattering data was treated using the Baxter sticky spheres model. The third phase formed in the case of DHOA displayed higher aggregation tendency compared to that of TBP. These studies have demonstrated that the nature of the diluents plays an important role in the aggregation behavior of the extracted species (reverse micelles). No third phase was observed in the case of chlorinated and aromatic diluents like chloroform and benzene during the extraction of Th(IV) from nitric acid medium. Theoretical calculations were also performed to gain insights into the binding of thorium nitrate with TBP and DHOA models. These calculations suggest that two to three molecules of both DHOA and TBP strongly coordinate to Th(NO3)4. It is noted that the highly charged Th(IV) cations are screened by nitrates and extractants which enables the interaction of second unit of such complex through noncovalent interactions.

Dynamic light scattering studies on the aggregation behavior of tributyl phosphate and straight chain dialkyl amides during thorium extraction

Dynamic light scattering (DLS) studies were carried out to investigate the aggregation behavior of 1.1M solutions of tributyl phosphate (TBP), N,N-dihexyl octanamide (DHOA) and of N,N-dihexyl decanamide (DHDA) in n-dodecane equilibrated with varying concentrations of nitric acid (0.1–6M) and of Th (10–200g/L). There was a gradual increase in thorium extraction with increased aqueous phase acidities. A significant enhancement in the aggregate sizes was observed with increasing concentration of thorium in the organic phase. The effect of 1-octanol as phase modifier was also investigated on the aggregation behavior of extracted species for TBP system.

High-capacity cathodes for lithium-ion batteries from nanostructured LiFePO4 synthesized by highly-flexible and scalable flame spray pyrolysis

Olivine, LiFePO4 is a promising cathode material for lithium-ion batteries due to its low cost, environmental acceptability and high stability. Its low electric conductivity prevented it for a long time from being used in large-scale applications. Decreasing its particle size along with carbon coating significantly improves electronic conductivity and lithium diffusion. With respect to the controlled formation of very small particles with large specific surface, gas-phase synthesis opens an economic and flexible route towards high-quality battery materials. Amorphous FePO4 was synthesized as precursor material for LiFePO4 by flame spray pyrolysis of a solution of iron acetylacetonate and tributyl phosphate in toluene. The pristine FePO4 with a specific surface from 126–218 m2 g−1 was post-processed to LiFePO4/C composite material via a solid-state reaction using Li2CO3 and glucose. The final olivine LiFePO4/C particles still showed a large specific surface of 24 m2 g−1 and were characterized using X-ray diffraction (XRD), electron microscopy, X-ray photoelectron spectrocopy (XPS) and elemental analysis. Electrochemical investigations of the final LiFePO4/C composites show reversible capacities of more than 145 mAh g−1 (about 115 mAh g−1 with respect to the total coating mass). The material supports high drain rates at 16 C while delivering 40 mAh g−1 and causes excellent cycle stability.