Dibutyl Butylphosphonate Research Articles

Solvent Extraction with Cyanex 923 to Remove Arsenic(V) from Solutions.

The removal of harmful arsenic(V) from aqueous solutions using Cyanex 923 (solvation extractant) was investigated using various experimental variables: equilibration time, the acidity of the aqueous phase, temperature, extractant and arsenic concentrations, and O/A ratio. Cyanex 923 extracted As(V) (and sulfuric acid) from acidic solutions; however, it could not be used to remove the metal from slightly acid or neutral solutions. The extraction of arsenic is exothermic and responded to the formation of H3AsO4·nL species in the organic phase (L represents the extractant, and the stoichiometric factor, n = 1 or 2, depends on the acidity of the aqueous phase). Extraction isotherms are derived from the experimental results. Both arsenic and sulfuric acid loaded onto the organic phase can be stripped with water, and stripping isotherms are also derived from the experimental results. The selectivity of the system against the presence of other metals (Cu(II), Ni(II), Bi(III), and Sb(III)) is investigated, and the ability of Cyanex 923 to extract As(V) and sulfuric acid compared to the use of other P=O-based solvation reagents, such dibutyl butylphosphonate (DBBP) and tri-butyl phosphate (TBP), is also investigated.

Pu distribution among mixed waste components at the Hanford legacy site, USA and implications to long-term migration

Beginning in 1943, process wastes containing approximately 1.85 × 1015 Bq (200 kg) of plutonium (Pu) were released into unlined cribs, trenches, and field tiles at the Hanford Site, Washington, USA. The 216-Z-9 (Z-9) unlined trench received over 4 × 106 L of mixed Pu processing waste from the Plutonium Finishing Plant (PFP) consisting of high ionic strength (∼ 5 M nitrate, ∼ 0.6 M aluminum), acidic (pH ∼ 2.5) solutions, which also contained the organic solvents: tributyl phosphate (TBP), dibutyl butylphosphonate (DBBP), carbon tetrachloride (CCl4), and lard oil. A small fraction of Pu migrated deep into the subsurface vadose zone to depths of 37 m, but the mechanisms controlling Pu migration beneath the trench are unknown. In this study, we determined Pu partitioning behavior in a series of binary and ternary batch experiments containing aqueous, organic, and solid phases representative of the waste constituents and natural sediments of the Z-9 trench in order to develop a conceptual model for the transport of Pu in the subsurface. Our results show that Pu at equilibrium with low pH, high nitrate waste and in the presence of a TBP/organic phase can migrate as a Pu-TBP-nitrate complex in the organic phase as long as the low pH and high nitrate concentrations are maintained. Reducing the nitrate concentrations or increasing the pH will lead to Pu partitioning into the aqueous phase from the organic phase with subsequent sorption to native Hanford sediments. The results of this work suggest that Pu migration in the subsurface is likely driven by weak sorption of aqueous Pu under low pH conditions as well as the formation of Pu-TBP-nitrate complexes in the organic phase. Long-term Pu migration will be limited by the transient nature of the low pH conditions and the dispersion of the nitrate plume.

Structure-Oriented Research on the Antiestrogenic Effect of Organophosphate Esters and the Potential Mechanism.

Organophosphate esters (OPEs) can exhibit various toxicities including endocrine disruption activity. Unfortunately, the low-dose endocrine-disrupting effects mediated by estrogen receptors (ERs) are commonly underestimated for OPEs and their metabolites. Here, structure-oriented research was performed to investigate the estrogenic/antiestrogenic effect of 13 OPEs (including three metabolites) and the potential mechanism. All of the OPEs exerted antiestrogenic activities in both E-screen and MVLN assays. OPEs with bulky substituents, such as phenyl rings (triphenyl phosphate (TPP), tricresyl phosphate (TCP), diphenylphosphoryl chloride, and diphenylphosphite) or relatively long alkyl chains (dibutylbutylphosphonate (DBBP)), exerted relatively strong ER antagonism potency at micromolar concentrations. The established quantitative structure-activity relationship indicated that the antiestrogenic activities of the OPEs mainly depended on the volume, leading eigenvalue, and hydrophobicity of the molecule. Molecular docking revealed that the three OPEs with the bulkiest substituents on the phosphate ester group (TPP, TCP, and DBBP) have a similar interaction mode to the classical ER antagonist 4-hydroxytamoxifen. The correlation between the antiestrogenic activity and the corresponding ER binding affinity was statistically significant, strongly suggesting that the OPEs possess the classical antagonism mechanism of interfering with the positioning of helix 12 in the ER.

Analysis of the aqueous solubility of trialkyl phosphates, dialkyl alkylphosphonates, dialkylphosphites and alkyl dialkylphosphinates

Linear free energy relationship (LFER) analysis based on the molar intrinsic volume (Vx), McGowan hydrophile‒lipophile balance (HLB) and cumulative Kabachnik constants (Σσϕ) of considered solutes has been performed for the solubility of trialkyl phosphates, dialkyl alkylphosphonates, dialkyl phosphites and alkyl dialkylphosphonates in pure water (called also as their aqueous solubility). The descriptors mentioned above are known for all considered solutes and are strongly correlated with their aqueous solubility. From the correlation found for trialkyl phosphates, dialkyl alkylphosphonates and dialkyl phosphites it follows that the mean contribution of each methylene group in their structure (Δlog Sw) is a constant for these homologous series and equal to − 0.41. It means that within of homologous series the aqueous solubility of succeeding solutes decreases regularly. The established increment has been further used as a tool for the preliminary selection of solutes whose aqueous solubility at 25 °C is in agreement with this condition. The adequate model (further denoted as AR model) based on the accessible data of temperature effects upon the aqueous solubility of tributyl phosphate, dibutyl butylphosphonate and butyl dibutylphosphinate has been formulated and then tested with positive results for the other solutes whose solubility is known at a selected constant temperature, e.g. at 25 °C. It should noticed, however, that in this case there are some serious restrictions. First, the interpretation and formulation of conclusions for the solutes which aqueous solubility is known at one selected temperature (e.g. 25 °C) or if it has been determined at a few temperatures only, should be made with care. Second, the obtained results with AR model cannot be used for prediction of temperature effects upon the aqueous solubility of such solutes. Simultaneously, the results obtained with AR model have been compared with those following from the modified Abraham model. Such comparison has been possible due to a significant progress in the different application of Abraham model for several organophosphorus derivatives as monobasic dialkyl- and diarylphosphoric acids, dialkyl- and diphenylphosphinic acids, trialkyl- and triaryl phosphates, dimethyl methylphosphonate, dialkylphosphites and some of trialkyl- and triarylphosphine oxides, respectively.

Solubility of dialkylalkyl phosphonates in supercritical carbon dioxide: Experimental and modeling approach

Dialkylalkyl phosphonates have found renewed interest in the selective extraction of actinides from different matrices. In this context, two dialkylalkyl phosphonates, dibutylbutyl phosphonate (DBBP) and diamylamyl phosphonate (DAAP) were synthesised and their solubilities in supercritical carbon dioxide (SCCO2) medium were determined in the pressure range of 10–25 MPa at 313–333 K. Solubility studies were carried out to examine their utility as ligands during supercritical fluid extraction of actinides. Solubilities of dialkylalkyl phosphonates ranged from 0.06 to 0.12 mole fraction. Experimental solubilities were correlated using Mendez-Santiago, Chrastil, solution theory with Wilson activity coefficient model and association model based on van Laar activity coefficient model. Comparison among these models revealed that the association model with van Laar activity coefficient model provides better solubility predictions. SCCO2 containing DAAP was employed for the (i) selective extraction of uranium in the presence of simulated fission products and (ii) extraction of uranyl nitrate from acidic medium.

Supercritical fluid extraction of uranium and thorium from nitric acid medium using organophosphorous compounds

Abstract In recent years, Supercritical Fluid Extraction (SFE) technique has been widely used for the extraction of metal ions. In the present study, extraction of uranium from nitric acid medium was investigated using supercritical carbon dioxide (Sc-CO2) containing various organophosphorous compounds such as trialkyl phosphates e.g. tri-iso-amyl phosphate (TiAP), tri-sec-butyl phosphate (TsBP) and tri-n-butyl phosphate (TBP), dialkylalkyl phosphonates, e.g. diamylamyl phosphonate (DAAP) and dibutyl butyl phosphonate (DBBP), dialkyl hydrogen phosphonates, e.g. dioctyl hydrogen phosphonate (DOHP), dioctylphosphineoxide (DOPO), trioctyl phosphine oxide (TOPO), n-octylphenyl N,N-diisobutyl carbamoylmethylphosphine oxide (CMPO) and di-2-ethyl-hexyl phosphoric acid (HDEHP). Some of these ligands have been investigated for the first time in the supercritical phase for the extraction of uranium. The extraction efficiency of uranium was studied with TiAP, DAAP and DBBP as a function of nitric acid concentration; the kinetics of the equilibration period (static extraction) and transportation of the metal complex (dynamic extraction) was investigated. The influence of pressure and temperature on the extraction behaviour of uranium with DAAP was studied from 4 N HNO3. The extraction efficiency of uranium from 4 N nitric acid medium was found to increase in the order of phosphates < phosphonates < HDEHP < TOPO < CMPO. In the case of phosphates and phosphonates, the maximum extraction of uranium was found to be from 4 N HNO3 medium. The acidic extractants, HDEHP and DOHP showed relatively higher extraction at lower acidities. The relative extraction of uranium and thorium from their mixture was also examined using Sc-CO2 containing phosphates, phosphonates and TOPO. The ligand, TsBP provided better fractionation between uranium and thorium compared to trialkyl phosphates, dialkyl alkyl phosphonates and TOPO.

All Solid State Chromium(III) Selective Potentiometric Sensor Based on 2-(1-(2-((3-(2-Hydroxyphenyl)-1H-pyrozol-1-yl)methyl)benzyl)-1H-pyrazol-3-yl)phenol

Highly selective all solid state electrochemical sensor based on a synthesized compound i.e. 2-(1-(2-((3-(2-hydroxyphenyl)-1H-pyrozol-1-yl)methyl)benzyl)-1H-pyrazol-3-yl)phenol (I) as an ionophore has been prepared and investigated for the selective quantification of chromium(III) ions. The effect of various plasticizers, viz. dibutyl phosphonate (DBP), dibutyl(butyl) phosphonate (DBBP), nitrophenyl octyl ether (NPOE), tris-(2-ethylhexyl)phosphonate (TEP), tri-butyl phosphonate (TBP), dioctyl phthalate (DOP), dioctyl sebacate (DOS), benzyl acetate (BA) and acetophenone (AP) along with anion excluders NaTPB (sodium tetraphenyl borate) and KClTPB (potassium(tetrakis-4-chlorophenyl)borate was also studied. The optimum composition of the best performing membrane contained (I):KClTPB:NPOE:PVC in the ratio 15 : 3 : 40 : 42 w/w. The sensor exhibited near Nernstian slope of 20.1±0.2 mV/decade of activity in the working concentration range of 1.2×10−7–1.0×10−1 M, and in a pH range of 3.8–4.5. The sensor exhibited a fast response time of 10 s and could be used for about 5 months without any considerable divergence in potentials. The proposed sensor showed very good selectivity over most of the common cations including Na+, Li+, K+, Cu2+, Sr2+, Ni2+, Co2+, Ba2+, Hg2+, Pb2+, Zn2+, Cs+, Mg2+, Cd2+, Al3+, Fe3+and La3+. The activity of Cr(III) ions was successfully determined in the industrial waste samples by using this sensor.

Development of potentiometric sensors for the selective determination of UO2 2+ ions

The construction and performance characteristics of poly(vinyl chloride) membrane electrodes for uranyl ions based on dibutyl butyl phosphonate (L1) and di-n-octyl phenyl phosphonate (L2) as ionophores, are reported. The optimized membrane electrodes based on L1 and L2 exhibited a Nernstian response for uranyl ions over a concentration range of 5.0 × 10−6–1.0 × 10−1 and 5.5 × 10−5–1.0 × 10−1 mol L−1in the pH range 2.1–3.4, with slopes of 28.6 and 29.7 mV decade−1, respectively. The optimized electrodes exhibit good selectivity for UO2 2+ ions over a wide variety of other metal ions. The electrodes exhibit a fast dynamic response of ~30 s. The developed sensors were used for potentiometric determination of uranyl ions concentration in different real samples and the obtained results agreed well with those obtained employing inductively coupled plasma optical emission spectrometer.

Solvent extraction of uranium from saline leach liquors using DEHPA/Alamine 336 mixed reagent

The presence of chloride in sulphuric acid leach liquors has a negative impact on the solvent extraction process for the recovery of uranium using tertiary amine reagents, such as Alamine 336. This can increase operating costs, and limit the use of saline water as plant process water. This study is based on the use of a mixed solvent containing DEHPA (di-2-ethylhexylphosphoric acid) and Alamine 336, and examines the performance of this system for uranium recovery from an overall process perspective. It investigates the impact of chloride, sulphate and acidity on uranium extraction and discusses the selectivity of the mixed reagent for uranium over iron (III) in the context of loading and selective scrubbing. The study also presents results of sulphuric acid (5–8 M H2SO4) and alkali (1 M Na2CO3) stripping of uranium, and the need for addition of phase modifiers such as TBP (tributylphosphate), DBBP (dibutyl-butyl phosphonate) and TOPO (trioctyl phosphine oxide), to prevent third phase formation.

Improved solvation routes for the Bunsen reaction in the sulphur iodine thermochemical cycle: Part II – Molecular solvent properties

Operating the Bunsen reaction in the presence of a molecular solvent has the potential to decrease the large excesses of water and iodine currently required and therefore to increase the efficiency of the sulphur iodine cycle. Tri-n-butyl phosphate (TBP) has been shown to extract HI into the solvent phase, however the TBP breaks down when treated thermally to recover the HI. Alternative solvents which also show a high extraction of HI, but that are stable in the presence of HI at high temperature, are needed. This paper investigates dibutylbutylphosphonate (DBBP) and Cyanex® 923 as alternatives to TBP. Both DBBP and Cyanex® 923 were shown to perform as well as or better than TBP against metrics including: HI extraction, H2SO4 extraction, SO2 solubility and I2 solubility. Using TGA, thermal recovery of the HI was not successful from DBBP, as the solvent broke down in a similar way to TBP. Small amounts of HI were recovered through distillation of Cyanex® 923, however the yield was low. Partial success was achieved by backwashing the HI loaded Cyanex® 923 with water. Further work is needed to assess the performance of the actual Bunsen reaction in each of these solvents and to find ways of recovering the HI from the solvent.

Studies on the Extraction of Actinides by Substituted Butyl Phosphonates

The extraction of actinides by homologs of dibutylalkyl phosphonates has been studied in detail. This study was taken up in order to understand the influence of the phosphorus-carbon bond in phosphonates on the extraction of actinides. In this context, dibutylhexyl phosphonate (DBHeP) and dibutyloctyl phosphonate (DBOP) were synthesized and characterized by various techniques. The physical properties of the two solvents and the extraction of nitric acid and actinides by these phosphonates were compared with those by dibutylbutyl phosphonate (DBBP). The physical properties such as density, viscosity, surface tension, refractive index, and solubility are reported here for the first time. Dispersion number, a dimensionless quantity that characterizes the ability of the solvent to separate from two-phase dispersion, is reported for all the three phosphonates. The extraction characteristics of actinides by these series of compounds are compared with those by tributyl phosphate (TBP).

Chemical studies on uranium extraction from concentrated phosphoric acid by using PC88A and DBBP mixture

Liquid–liquid extraction of U (VI) from concentrated phosphoric acid by using (2-ethyl hexyl) phosphonic acid, mono (2-ethyl hexyl) ester (PC88A) and di-butyl butyl phosphonate (DBBP) has been investigated. The effect of different factors affecting the extraction process (PC88A concentration, DBBP concentration, shaking time, aqueous/organic phase ratio, phosphoric acid concentration and effect of diluents) have been investigated. The obtained data of temperature on the extraction showed that the enthalpy change is −17.15 kJ mol−1. Uranium was extracted from the strip liquor by using di (2-ethylhexyl) phosphoric acid and tri-octyl phosphine oxide mixture and finally converted to a high purity UO3 product using precipitation with hydrogen peroxide and heat treatment at 365 °C.

Anion recognition through amide-based dendritic molecule: A poly(vinyl chloride) based sensor for nitrate ion

Poly(vinyl chloride) (PVC)-based membranes of N,N-bis-succinamide-based dendritic molecule with tetrabutyl ammonium bromide (TBAB) as a cation inhibitor and dibutylphthalate (DBP), dioctylphthalate (DOP), dibutyl (butyl) phosphonate (DBBP) and 1-chloronaphthalene (CN) as plasticizing solvent mediators were prepared and used as nitrate ion-selective electrodes. Optimum performance was observed with the membrane having I–PVC–TBAB–DBP in the ratio 1:33:1:65 (w/w). The electrode has a linear response to nitrate with a detection limit of 3.9 × 10 −5 ± 0.07 M and Nernstian compliance (57.0 ± 0.2 mV/decade) between pH 2.8 and 9.6 with a fast response time of about 20 s. The selectivity coefficient values of the order of 0.001 for mono-; bi- and trivalent anions; indicate high selectivity for nitrate ions over these anions. The preparation procedure of the electrode is very easy and inexpensive. The electrodes were used over a period of 45 days with good reproducibility. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of nitrate ions in waste water samples.

Liquid–liquid extraction of uranium from Egyptian phosphoric acid using a synergistic D2EHPA–DBBP mixture

Extraction of uranium from Egyptian phosphoric acid with synergistic mixture of di-2-ethylhexylphosphoric acid (D2EHPA) and di-butyl butyl phosphonate (DBBP) is reported in this paper. The influence of various factors such as D2EHPA concentration, DBBP concentration, phosphoric acid concentration, contact time, aqueous: organic phase’s ratio (aq:org) and temperature on the degree of extraction has been established. The data on the effect of temperature on the extraction showed that the enthalpy change is −23.12 kJ/mol. Uranium extracted by D2EHPA–DBBP is further subjected to a second cycle of extraction and scrubbing impurities. The uranium is finally converted to a high purity UO3 product using precipitation with hydrogen peroxide and heat treatment at 375 °C.

Crown ether-dendrimer based potentiometric Na + sensor electrode

Poly(vinyl chloride) (PVC)-based membranes of silacrown end grafted carbosilane dendrimer (I) with sodium tetraphenylborate (NaTPB) as an anion inhibitor and dibutylphthalate (DBP), dioctylphthalate (DOP), dibutyl (butyl) phosphonate (DBBP) and 1-chloronaphthalene (CN) as plasticizing solvent mediators were prepared and used as Na +-selective electrodes. Optimum performance was observed with the membrane having I–PVC–NaTPB–DOP in the ratio 1:33:1:65 (w/w). The electrode works well over a wide concentration range 1.5 × 10 −6–1.0 × 10 −1 M with Nernstian compliance 56.0 mV/decade between pH 5.8 and 9.2 with a fast response time of about 15 s. The selectivity relative to alkali, alkaline earth and transition heavy metal ions is good. The selectivity coefficient values towards potassium ions have been calculated to be 2.3 × 10 −4 by utilizing Fixed Interference Method. The proposed electrode could be used for at least 2 months without considerable alteration in its potential. The effect of nonionic surfactants Tween 20, Tween 80, Triton X 100, Span 20 and Span 60 on the potentiometric properties of the sodium selective membrane was also studied.

A novel ion selective sensor for promethium determination

This is a first promethium 145 ion-selective sensor based on the comparative study of two Schiff base ligands (X 1 and X 2) as neutral ionophores. Effect of various plasticizers: 2-nitrophenyloctylether ( o-NPOE), dibutyl phosphonate (DBP), dioctylphthalate (DOP), tri-(2-ethylhexyl) phosphate (TEHP), dibutyl butylphosphonate (DBBP), chloronaphthalene (CN) and anion excluders: potassium tetrakis (p-chloropheny1) borate (KTpClPB), sodiumtetraphenylborate (NaTPB) and oleic acid (OA) have been studied. The membrane with a composition of ionophore (X 1/X 2):KTpClPB:PVC: o-NPOE (w/w, %) in the ratio of 5:5:30:60 exhibited best performance. The best responsive membrane sensors (8 and 21) exhibited working concentration range of 4.5 × 10 −7–1.0 × 10 −2 M and 3.5 × 10 −6–1.0 × 10 −2 M with a detection limits of 3.2 × 10 −7 M and 2.3 × 10 −6 M and Nernstian slopes of 20.0 ± 0.5, 19.5 ± 0.5 mV decade −1 of activity, respectively. The sensor no. 8 works satisfactorily in partially non-aqueous media up to 10% (v/v) content of methanol, ethanol and acetonitrile. Analytical application of the proposed sensor has been demonstrated in determination of promethium (III) ions in spiked water samples.

Optimization of tramadol–PVC membrane electrodes using miscellaneous plasticizers and ion-pair complexes

Effect of the ISE membrane composition on the characteristics of the tramadol–PVC-electrodes has been investigated. The parameters studied include the effect of the plasticizer and the effect of the ion-pair complex. The plasticizers used were 2-nitrophenyl octyl ether (2-NPOE), dioctyl phthalate (DOP), dibutyl phthalate (DBP), tris(2-ethylhexyl) phosphate (TEPh), dioctyl sebacate (DOS), tributyl phosphate (TBPh) and dibutyl butyl phosphonate (DBBPh) and the ion-pair complexes were tramadolium–silicotungstate (TD–ST), silicomolybdate (TD–SM). These electrodes were fully characterized in terms of composition, life span, usable pH range and working concentration range. The results showed that the best combination was TD–ST as the ion-pair complex and DBP as the plasticizer that produced the electrode with favorable characteristics. Another electrode using TD–SM was tested and produced close results. The present electrodes show clear discrimination of tramadol hydrochloride from several inorganic, organic ions, sugars and some common drug excipients. The sensors were applied for determination of tramadol hydrochloride in urine, milk and pharmaceutical preparations using potentiometric determination, standard addition and the calibration curve methods. The results obtained were satisfactory with excellent percentage recovery comparable and sometimes better than those obtained by other routine methods for the assay.

Comparative studies on Tb (III)-selective PVC membrane sensors

A new terbium selective sensor based on N-(2-hydroxyphenyl)-3-(2-hydroxyphenylhydroxyphenylimino)-N-phenylbutanamidine ( L 1 ) and N,N′-bis((1H-indole-3-yl)methylene)butane-1,4 diamine ( L 2 ) as a ionophore is reported. Effect of various plasticizers; 2-nitrophenyloctylether ( o-NPOE), dibutyl butylphosphonate (DBBP), chloronaphthelene (CN), dioctylphthalate (DOP) and tri-(2-ethylhexyl)phosphate (TEHP) with anion excluder, potassium tetrakis (p-chloropheny1)borate (KTpClPB) have been studied. The membrane with a composition of ionophore ( L 1 ):KTpClPB:PVC: o-NPOE (w/w, %) in ratio of 3.0:5.0:30.0:62.0 exhibited enhanced selectivity towards terbium ions (III) in the concentration range of 3.5 × 10 −7 to 1.0 × 10 −2 M with a detection limit of 1.2 × 10 −7 M and a Nernstian slope (20.0 ± 0.5 mV dec −1 activity). The sensors showed the working pH range to be 3.5–7.5 with response time of 11 s. The sensor has been found to work satisfactorily in partially non-aqueous media up to 15% (v/v) content of methanol, ethanol or acetonitrile and could be used for a period of 3 months. The selectivity coefficients indicated high selectivity for terbium (III). The fast and stable response, good reproducibility and long-term stability of the sensors were observed. The application of the sensor has been demonstrated in determination of terbium (III) ions in spiked water samples.

Studies on the Extraction of Actinides by Dibutylbutyl Phosphonate

Dibutylbutyl phosphonate (DBBP) was synthesized by the Michaelis Becker reaction, and was characterized by elemental analysis, IR, and 31P NMR. The extraction of U(VI), Th(IV), Pu(IV), Fe(III), and Am(III) by 1.1 M DBBP in n-dodecane as a function of nitric acid concentration was studied, and the results are compared with the extraction behavior of these ions with tributyl phosphate (TBP) and diamylamyl phosphonate (DAAP) in n-dodecane. The physical properties of the extractant such as the density, surface tension, viscosity, aqueous solubility, and phase-disengagement time with 1.1 M DBBP/n-dodecane have been measured and compared with those of 1.1 M TBP/n-dodecane and 1.1 M DAAP/n-dodecane. Studies on the third-phase formation behavior of 1.1 M DBBP/n-dodecane with U(VI) and Th(IV) nitrates in nitric acid medium have been carried out, and the results are compared with the TBP and DAAP systems. Studies were also carried out to study the U-Fe separation by DBBP impregnated on XAD-4 resin.

Extraction of americium(VI) by a neutral phosphonate ligand

Recently the use of the more unusual hexavalent oxidation state of americium has been receiving increased attention for the purpose of developing an efficient Am/Cm or Am/lanthanide separation system. We have already demonstrated the feasibility of performing this separation with 30% TBP in dodecane, and are now looking at different extractants to increase Am(VI) distribution ratios. Following on from this the extraction of bismuth oxidized americium from nitric acid solutions by dibutyl butyl phosphonate has been studied. The results of this study indicate that increasing the basicity of the extractant molecule has significantly improved the extraction efficiency.