Extraction of uranium(VI) and thorium(IV) ions from nitric acid solutions by N,N,N′,N′-tetrabutyladipicamide

A new symmetrical diamide, the straight-chain alakyl substituted neutral tetrabutyladipicamide (TBAA) has been synthesized, characterized and used for the extraction of U(V) and Th(IV) from nitric acid solutions in a diluent composed of 50% 1,2,4-trimethylbenzene (TMB) and 50% kerosene (OK). Extraction distribution coefficients of U(VI) and Th(IV) as a function of aqueous nitric acid concentration, extractant concentration and temperature have been studied. Back-extraction of U(VI) and Th(IV) from organic phases by dilute nitric acid has been undertaken. From the data, the compositions of extracted species, equilibrium constants and enthalpies of extraction reactions have also been calculated.     

Solvent extraction of Ga(III) and In(III) from aqueous halide media by adogen-364

Adogen-364 has been used for the extraction ofgallium(III) and indium(III) from halogen acid solutions, and the dependence of the extraction on chloride, bromide and iodide ion concentration studied. The separation of Ga(III), In(III) and Al(III) is reported and some conclusions have been drawn about the stoichiometry of the extracted species.     

Extraction of lanthanoids and some associated elements by mono-(2-ethylhexyl)phosphoric acid and their separations

Mono-(2-ethylhexyl)phosphoric acid (H₂MEHP) has been used to study the extraction of some lanthanoids and other associated elements from nitric acid medium. Effect of various variables like kind of diluent, concentration of metal ion, nitric acid and extractant has been investigated. Based on distribution data, it was possible to achieve some separations of lighter lanthanoids from metals like titanium, zirconium, thorium and uranium with high separation factors.     

Bis(2-ethylhexyl)sulfoxide as an extractant for americium(III) from aqueous nitrate media

Solven extraction separation of americium(III) from dilute aqueous nitrate media into n-dodecane by bis(2-ethylhexyl)sulfoxide (BESO) has been investigated over a wide range of experimentgal conditioins. Very poor extractablity of Am(III), necessitated the use of calcium nitrate as the salting-out agent. Effects of certain variables such as acidity, extractant concentration, salting-out agent concentration, organic diluents on the metal extraction by BESO have been examined in detail. By increasing the concentration of BESO in organic phase or calcium nitrate in aqueous phase, nearly quantitative extraction of americium even from moderate acidity is accomplished. Slope analyses applied to Am(III) distribution experiments from acidic nitrate solutions indicate predominant formation of the risolvated organic phase complex, Am(NO₃)₃)·3BESO for which equilibrium constant is found to be, log K_x=1.99. Extraction behavior of Am(III) has also been evlauated in the presence of several water-miscible polar organic solvents to stuy their possible synergistic effects on its extraction. Extractability of americium increased 5 to 10-fold withi increasing conentration of some of these additives, with maximum enhancement being observed in the presence of acetone or acetonitrile. Recovery of BESO from loaded americium is easily obtained using dilute nitric acid as the strippant.     

Sulphuric acid influence on liquid-liquid extraction of Co(II) and Zn(II) by MIBK from NH(4)SCN medium

Liquid-liquid extraction of Co(II) and Zn(II) by methylisobutylcetone (MIBK) has been studied systematically from NH(4)SCN/H(2)SO(4) media. The influence of sulphuric acid concentration on the percentage of extraction of Co(II) and Zn(II) has been discussed. It is shown that sulphuric acid concentration has not the same effect on distribution curves of Co(II) and Zn(II). Thus, it is possible to have a separation of Zn(II) of Co(II) when [NH(4)SCN] is 0.5 mol l(-1) and [H(2)SO(4)] is about 2 mol l(-1). Under these conditions the separation factor (S(Zn/Co)) is around 580. The results are treated in terms of thermodynamic activities in aqueous phase, to determine the composition of the extracted complexes (M:SCN(-)) and to discuss the extraction mechanism.     

Studies on Liquid‐Liquid Extraction and Recovery of Bismuth(III) from Succinate Media Using 2‐Octylaminopyridine in Chloroform

A procedure is described for the liquid‐liquid extraction and recovery of bismuth(III) from succinate solution using 2‐octylaminopyridine (2‐OAP) as an extractant. The quantitative extraction of bismuth(III) occurs from 0.004 to 0.007 M sodium succinate solution of pH 2.5‐10 using 0.036 M 2‐OAP in chloroform. The extracted metal ion has been recovered by stripping with (3 × 10 mL) 0.5 M nitric acid. The log‐log plot of distribution ratio versus succinate concentration and distribution ratio versus 2‐OAP concentration gave slopes of 2.0 and 0.9, respectively, indicating a metal‐succinate ratio of 1:2 and a metal: 2‐OAP ratio of 1:1. The ion pair complex has a high distribution ratio in chloroform, while other solvents are poor. The extractants are stable towards prolonged acid contacts and there is no loss in its extraction efficiency even after recycling ten times. The extraction behaviour of some commonly associated metal ions, namely Ga(III), Cd(II), Zn(II), Cr(VI), Cu(II), Ba(II), Sb(III), Sn(IV), Tl(I) and Pb(II), has also been investigated. Based on partition data, conditions have been identified for attaining some separations of bismuth(III) from other metal ions; these conditions are extended for the recovery of pure bismuth from ore and alloys. Thermodynamic quantities for the extraction process were calculated.     

Extraction of gold(III) with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl-methyl)-pentan-3-ol from hydrochloric acid solutions

Extraction of gold(III) with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)-pentan-3-ol from 3 M hydrochloric acid solutions (with chloroform as a diluent) has been studied. Optimal extraction conditions have been found. The reagent has been shown to extract efficiently metal ion from solutions containing 3 M hydrochloric acid due to formation of coordination bond between gold(III) and the N4 atom of the triazole ring. The coordination mechanism of gold(III) extraction has been proposed on the basis of the data obtained. Concentration constants of extraction have been calculated, and the thermodynamic parameters of extraction have been determined.     

The use of 5-(4-pyridyl)nonane for the separation of chromium(vi) from fission products in hydrochloric acid media

The distribution of chromium(VI) between 5-(4-pyridyl)nonane in benzene and hydrochloric acid media has been studied as a function of the concentration of the acid, extractant, chromium(VI), chloride and a few other ions. The extraction mechanism and the composition of the extracted complexes of Cr(VI) have been proposed. The separation of Cr(VI) from uranium, thorium and fission products in 3M hydrochloric acid has been achieved.     

Extraction and separation of mercury(II) using triisobutyl phosphine sulfide (TIBPS/Cyanex) as an extractant and its application to industrial effluent

Studies have been carried out on the extraction of Hg(II) along with Cr(III), Fe(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Ag(I), from mineral acid media using TIBPS. The effect of different variables influencing extraction of Hg(II), such as, mineral acid used, nature of diluent, concentration of metal ion and extractant has been investigated. Based on the partition data some binary separations from Hg(II) have been achieved. The potential of the extractant for decontaminating Hg from paper industry effluent has been assessed.     

Extraction of uranium(VI) by bis(hexylsulfinyl)methane

The extraction of uranium(VI) with bis(hexylsulfinyl)methane (BHxSM) from nitric acid aqueous solution has been investigated. It was found that the extraction increased with increasing nitric acid concentration up 8.5 mol/l and then decreased. Extraction distribution ratio also increased with the bis(hexylsulfinyl)methane concentration. The extraction species appear to be UO₂(NO₃)₂ ^.2BHxSM. The influences of temperature, salting-out concentration and oxalate concentration on the extraction equilibrium were also investigated, and the enthalpy of the extraction reaction was obtained. The result shows that the reaction of uranium(VI) extraction with BHxSM is an exothermic one.     

Extraction of cadmium(II) by organophosphorus compounds

The extraction of cadmium(II) by di-(2-ethylhexyl) phosphoric acid dissolved in tetradecane from aqueous chloride and perchlorate solutions has been studied at 25°C. The distribution of the metal has been determined as a function of metal and DEHPA concentrations. Distribution data have been treated both graphically and numerically using the program LETAGROP-DISTR (Acta Chem. Scand. 1971, 25, 1521) and the composition of the extracted species into the organic phase has been determined. The extraction constants for these species are given in Table 1.     

Solvent extraction of hafnium(IV) by N-benzoyl-N-phenylhydroxylamine

The extraction of hafnium(IV) tracer by N-benzoyl-n-phenylhydroxylamine (BPHA) from 1M perchloric acid has been investigated and stability constants have been calculated for the complexes Hf(BPHA)(i)((4-i)+) (i = 1cdots, three dots, centered4). It was found that variation of perchlorate concentration in the range 0.5-2.0M at constant acidity has no effect on the distribution of hafnium.     

Extraction of U(VI) with unsymmetrical N-methyl-N-octyl alkylamides in toluene

Summary This work is focused on the extraction of U(VI) with three new unsymmetrical monoamides, N-methyl-N-octyloctylamide (MOOA), N-methyl-N-octyldecanamide (MODA), and N-methyl-N-octyldodecanamide (MODOA), from nitric acid solution employing toluene as diluent. The effects of nitric acid, sodium nitrate and extractant concentrations and also the temperature on the distribution ratio have been investigated. The extracted species were studied by IR spectrometry.     

Extraction chromatographic study of aluminium(III) and mutual separation of aluminium(III), gallium(III), indium(III) and thallium(III) with N-n-octylaniline

A selective method has been developed for extraction chromatographic studies of aluminium(III) and its separation from several metal ions with a chromatographic column containing N-n-octylaniline (liquid anion exchanger) coated on silanized silica gel as a stationary phase. The aluminium(III) was quantitatively extracted with the 0.065 mol/L N-n-octylaninine from 0.013 to 0.05 mol/L sodium succinate at a flow rate of 1.0 mL/min. The extracted metal ion has been recovered by eluting with 25.0 mL of 0.05 mol/L hydrochloric acid and estimated spectrophotometrically with aurintricarboxylic acid. The effects of the acid concentration, the reagent concentration, the flow rate and the eluting agents have been investigated. The log-log plots of distribution coefficient (KdAl(III)) versus N-n-octylaniline concentrationin 0.005 and 0.007 mol/L sodium succinate gave theslopes 0.5 and 0.7 respectively and showed theprobable composition of theextracted species was 1:1 (metal to amine ratio) and the nature of extracted species is [RR''NH2+ Al succinate2-] org. .The extraction of aluminium(III) was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. Aluminium(III) has been separated from multicomponent mixtures, pharmaceutical samples and synthetic mixtures corresponding to alloys. A scheme for mutual separation of aluminium(III), indium(III), gallium(III) and thallium(III) has been developed by using suitable masking agents. The method is fast, accurate and precise.     

Solvation of thiocyanate complexes of mercury(II) by 2-hexylpyridine from aqueous mineral acid solutions

The extraction of trace amounts of mercury(II) by 2-hexylpyridine dissolved in benzene from aqueous mineral acid solutions has been studied. The replacement of chloride, nitrate and sulfate ions by the potentially ambidentate, linear and less basic thiocyanate group offers interestingly high extraction coefficients. The value of the distribution coefficients may be lowered by complexing mercury with oxalate, thiosulfate, acetate or citrate ions in the aqueous phase. The possible mechanism of extraction has been discussed in the light of the results of extraction isotherms and slope analysis data. Distribution coefficients and separation factors of several metal ions relative to mercury(II) are reported for the three mineral acid systems and the possible removal of mercury along with some other inorganic pollutants from aqueous solutions is suggested.     

Synergistic extraction of cobalt(II) by tri-octylamine and neutral donors

This work reports a study on the synergistic extraction of cobalt(II), spiked with⁶⁰Co from hydrochloric acid solutions by mixtures of trioctylamine (TOA) and neutral organophosphorous donors into carbon tetrachloride. Synergistic coefficients and adduct formation constants have been evaluated from distribution measurements and correlated with the basic character of donors.     

N,N,N',N'-Tetrabutyladipicamide as a new extractant in toluene of nitric acid and uranium (VI)

N,N,N',N'-Tetrabutyladipicamide (TBAA) was used for the extraction of nitric acid and uranyl(II) ion from nitric acid media into toluene. The effects of nitric acid, uranyl(II) ion, and extractant concentration, temperature and back extraction on the distribution coefficient of uranyl(II) ion have been studied. The main adduct of TBAA and HNO₃ is TBAA·HNO₃ in 1.0 mol/l nitric acid solution. The 1:2:2 complex of uranyl(II) ion, nitrate ion and TBAA as extracted species is further confirmed by IR spectra of the extraction of uranyl(II) ion with TBAA. The values of the thermodynamic parameters have also been calculated.     

Extraction of Fe(III) by n-dodecanoic acid dissolved in toluene

The extraction of Fe(III) from a nitrate medium of ionic strength 1.0 mol dm⁻³ by n-dodecanoic acid (HA) dissolved in toluene has been studied by distribution measurements. Experimental data, treated by different graphical and numerical methods, have been explained assuming the extraction of the species (FeA₃)₃ into the organic phase as well as the formation of a Fe(III)-HA complex in the aqueous phase.     

Investigations on the use of 4-(5-Nonyl) pyridine as an extractant for chlorocomplexes of gallium(III)

A study of the distribution of gallium(III) between hydrochloric acid solutions and 0.1M 4-(5-nonyl)-pyridine in benzene has been undertaken. Gallium can be quantitatively extracted from moderate to concentrated acid solutions and also from dilute acid solutions containing high concentrations of neutral cations of high charge density. The effects of acidity, the solvent concentration and diverse ions on the extraction have been investigated. An attempt has been made to elucidate the stoichiometry of the extracted species. The formulation of (NP_y H)⁺ GaCl ₄ ⁻ ) and (NP_y−H−NP_y)⁺ GaCl ₄ ⁻ is expected at macro and trace concentrations of the metal. The extraction coefficients of several elements have been recorded under conditions optional for the extraction of gallium; and their factors for separations are estimated.     

The extraction of beryllium(II) by di-(2-ethyl hexyl)-phosphoric acid from sulphate media

The distribution of Be(II) between aqueous sulphuric acid solutions and organic phases of di-(2-ethyl hexyl)-phosphoric acid (HDEHP) has been described. The dependence of extraction on contact time, acidity, metal and extractant concentration, diluent type and temperature was thoroughly investigated. The possible mechanism of the extraction is discussed on the basis of results obtained.