Extraction behavior of Tm(III), Dy(III) and Sm(III) lanthanide with N-benzoyl-N-phenylhydroxalamine

The extraction of Sm(III), Dy(III) and Tm(III) with N-benzoyl-N-phenylhydroxalamine (BPHA) in benzene at pH range (1–10) has been studied. Quantitative separation was found in borate media at pH 8. The slope analysis showed that the extracted complex was M(BPHA)₃, where M=Sm(III), Dy(III) and Tm(III). The effect of various masking agents indicated that EDTA, oxalate, fluoride, phosphate and citrate, interfered in this study. Decontamination study showed that Cu(II), Zn(II), Ni(II), Co(II), Cr(III), Sc(III) and Fe(III) had very poor separation factors, whereas Sn(II), Cd(II), In(III), Ru(II), Hg(II), Ag(I), Ta(V) and Hf(IV) had very large separation factor. The effect of different diluents showed that carbontetrachloride, chloroform, benzene, toluene, nitrobenzene dichloromethane, MIBK and cyclohexanone were equally good for extraction except TBP due to ion association.     

Solvent extraction and separation of gallium(III), indium(III), and thallium(III) with tributylphosphate

A systematic study has been made of the solvent extraction behaviour of milligram amounts of gallium(III), indium(III), and thallium(III) with TBP from hydrochloric acid, and of thallium(III) from nitric acid, sulphuric acid and buffer solutions of different pH. The effect of the metal ion concentration, acid concentration, reagent concentration, salting-out agent, and diverse ions have been critically examined. A scheme for separation of gallium(III), indium(III), and thallium(III) from each other and for their determination is proposed.     

Ligandless cloud point extraction of Cr(III), Pb(II), Cu(II), Ni(II), Bi(III), and Cd(II) ions in environmental samples with Tween 80 and flame atomic absorption spectrometric determination

A cloud point extraction (CPE) procedure has been developed for the determination trace amounts of Cr(III), Pb(II), Cu(II), Ni(II), Bi(III), and Cd(II) ions by using flame atomic absorption spectrometry. The proposed cloud point extraction method was based on cloud point extraction of analyte metal ions without ligand using Tween 80 as surfactant. The surfactant-rich phase was dissolved with 1.0 mL 1.0 mol L⁻¹ HNO₃ in methanol to decrease the viscosity. The analytical parameters were investigated such as pH, surfactant concentration, incubation temperature, and sample volume, etc. Accuracy of method was checked analysis by reference material and spiked samples. Developed method was applied to several matrices such as water, food and pharmaceutical samples. The detection limits of proposed method were calculated 2.8, 7.2, 0.4, 1.1, 0.8 and 1.7 μg L⁻¹ for Cr(III), Pb(II), Cu(II), Ni(II), Bi(III), and Cd(II), respectively.     

Highly sensitive spectrofluorometry of europium(III) as its benzoyltrifluoroacetone complex with trioctylphosphine oxide by means of solvent extraction and vacuum sublimation

Summary A new method for the highly sensitive fluorometric determination of europium(III) as its benzoyltrifluoroacetone (BFA) complex with trioctylphosphine oxide (TOPO) without uncombined BFA in n-hexane has been established by means of solvent extraction and vacuum sublimation. The effect of various factors on the fluorescence intensity of europium(III) was investigated. The fluorescence intensity was measured at 620 nm against rhodamine B as an internal standard under the excitation at 335 nm. It was found that a heating treatment gave rise to the enhancement of the fluorescence intensity for about twice times compared with that without heating treatment. Excellent linearity of the calibration curve of europium(III) was obtained in the range of 0–100 ppb. A few ppb of europium(III) can still be detected with this method. All 13 rare earth metals and cobalt(II) tested gave a somewhat positive error. Aluminium(III), iron(III), and copper(II) caused a negative error. The interference of aluminium(III) and iron(III) was removed by extraction with 0.1 mol/l 8-quinolinol in chloroform at pH 4.0, while the problem of cobalt(II) and copper(II) was solved by masking with 0.1 mol/l Na₂S₂O₃ in aqueous solution.

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Hochempfindliche spektrofluorimetrische Bestimmung von Europium(III) als Benzoyltrifluoracetonkomplex mit Trioctylphosphinoxid mit Hilfe der Lösungsextraktion und Vakuumsublimation

     

Selective extraction of thallium(III) in the presence of gallium(III), indium(III), bismuth(III) and antimony(III) by salting-out of an aqueous mixture of 2-propanol

Thallium(III), in the presence of other triply charged ions such as gallium, indium, bismuth and antimony in aqueous solution, was quantitatively and selectively extracted into 2-propanol/water phase by addition of NaCl ranging from 2.5 to 4.0 mol dm⁻³. The extraction efficiencies of gallium, indium, bismuth and antimony were much lower than that of thallium(III). Thus a maximal selective separation of thallium(III) from these elements could be attained using a 2-propanol/water mixture. Thallium(III) was extracted as TlCl₄⁻ with Na⁺. The detailed extraction mechanism in the presence of chloride, water in the organic phase and counter ions is discussed.     

Utility of 1-octanol/octane mixed solvents for the solvent extraction of aluminum(III), gallium(III), and indium(III) with 8-quinolinol.

Using 1-octanol/octane mixed solvents, the extraction of aluminum(III), gallium(III) and indium(III) with 8-quinolinol was carried out at 25 degrees C. The formation constants of the respective metal(III) 8-quinolinolates in the aqueous phase and their partition constants between the mixed solvents and water were determined based on an analysis of the extraction equilibria. The relationship between the partition constants of 8-quinolinol and its complexes was analyzed by the regular solution theory. The molar volumes of aluminum(III), gallium(III) and indium(III) 8-quinolinolates, calculated from the present results, suggest that the electrostriction effect functions in complex forming. It has been found that octane/1-octanol mixed solvents were available not only for the extraction of metal ions, but also for determining the formation constants of these metal 8-quinolinolates in the aqueous phase and their partition constants.     

Extraction of Sm(III), Gd(III) and Ho(III) ions with picrolonic acid in methylisobutylketone

Summary Picrolonic acid (HPA) in methylisobutylketone (MIBK) (0.01 mol^. dm^-3) has been used for the extraction of lanthanide(III) ions such as Sm(III), Gd(III) and Ho(III) (Me) (~3^. 10^-6mol^. dm^-3) from pH 1-2 buffer solutions of 0.1 mol^. dm^-3(H⁺, Cl^-) ionic strength and quantitative extraction (>95%) was found at pH 2. Through slope analysis the composition of the organometallic adduct responsible for the extraction came out to be M(PA)₃. The conditional equilibrium constant values, log K_ex, were deduced to be 2.60±0.01, 2.09±0.01 and 1.44±0.03 for these lanthanide(III) ions, respectively. The metals in concentration up to ~2.5^. 10^-4mol^. dm^-3can be quantitatively extracted by the proposed system. Among the various anions, fluoride, oxalate and cyanide ions (~3.0^. 10^-4mol^. dm^-3) and, among the cations, Zn(II) Cu(II), Co(II) and Fe(III) reduced the lanthanide extraction. The extraction of various other metal ions at the optimized conditions of Me extraction for this series of lanthanide ions was also studied and high separation factors (10²-10³) were obtained showing the good selectivity of this extraction system.     

Preconcentration of iron (III), cobalt (II) and copper (II) nitroso-R complexes on tetradecyldimethylbenzylammonium iodide-naphthalene adsorbent

Iron, cobalt and copper form coloured water soluble anionic complexes with disodium 1-nitroso-2-naphthol-3-6-disulphonate (nitroso R-salt). The anionic complex is retained quantitatively as a water insoluble neutral ion associated complex (M-nitroso R-TDBA) on tetradecyldimethylbenzylammonium iodide on naphthalene (TDBA(+)I(-)-naphthalene) packed column in the pH range of: Fe(III): 3.1-6.5, Co: 3.4-8.5 and Cu 5.9-8.0 when their solutions are passed individually over this adsorbent at a flow rate of 0.5-5.0 ml/min. The solid mass consisting of an ion associated metal complex along with naphthalene is dissolved out of the column with 5 ml dimethylformamide/chloroform and metals are determined spectrophotometrically. The absorbance is measured at 710 nm for iron, 425 nm for cobalt and 480 nm for copper. Beers law is obeyed in the concentration range 9.2-82 mug of iron, 425 nm for cobalt cobalt and 3.0-62 mug of copper in 5 ml of final DMF/CHCl(3) solution. The molar absorptivities are calculated to be Fe: 7.58 x 10(3), Co: 1.33 x 10(4) and Cu: 4.92 x 10(4)M(-1)cm(-1). Ten replicate determinations containing 25 mug of iron, 9.96 mug of cobalt and 3.17 mug of copper gave mean absorbances 0.677, 0.450 and 0.490 with relative standard deviations of 0.88, 0.98 and 0.92%, respectively. The interference of large number of metals and anions on the estimations of these metals has been studied. The optimized conditions so developed have been employed for the trace determination of these metals in standard alloys, waste water and fly ash samples.     

Polarographic analytical determination of Hg(II), Cu(II), Cd(II), As(III), Sb(III), Ti(IV) and U(VI) in the presence of Fe(III)

The analytical determination of Hg(II), Cu(II), Cd(II), As(III), Sb(III), Ti(IV) and U(VI) in the presence of Fe(III) and 1 M H₂SO₄ are investigated using the polarographic technique. The wave corresponding to the reduction of Fe(III) to Fe(II) was found to be completely suppressed by the addition of 1% pyrogallol. Thus, different mixtures of these elements, viz. Hg(II), Cu(II), Cd(II), As(III) and Fe(III)-mixture (A), Cu(II), Cd(II), Sb(III), As(III) and Fe(III)-mixture (B), and Cu(II), Cd(II), Ti(IV), U(VI) and Fe(III)-mixture (C), were quantitatively determined using 1% pyrogallol and 1 M H₂SO₄ as supporting electrolyte. The i₁/c results give excellent correlations in each case, as indicated from the results of leastsquares regression analysis.     

Determination of Cu(III) in semiconductor ceramics using cationic violet reagent

A method is presented for the determination of Cu(III) ion in semiconductor ceramic materials. It is based on (a) the reaction of copper(III) with Fe(II) ions, (b) the quantitative formation of Fe(III) ions, (c) liquid-liquid extraction of Fe(III) in the form of an ion associate between the FeCl ₄ ^- anion with a Cationic Violet dye, and (d) spectrophotometric quantitation of the ion associate. All processes are executed in a single sequence of steps. The absorbance of the colored extracts obeys Beer's law in the range from 0.16 to 1.92 mg L^?1 of Cu(III). The molar absorptivities range from 38,000 to 82,000 L mol^?1 cm^?1 depending on the kind of extractant used. The effects of other ions on the recovery of Cu(III) were studied, and those that generally occur with copper in semiconductor samples do not interfere.     

Solvent Extraction Separation of Iridium(III) from Rhodium(III) by N-n-Octylaniline

The use ofN-n-octylaniline for the extraction of iridium(III) from malonate media is studied at pH 8.5. Iridium(III) extracted in the organic phase was stripped with 2.0 M hydrochloric acid and was determined spectrophotometrically by the stannous chloride–hydrobromic acid method at 385 nm. The extraction system is studied as a function of the equilibration time, diluent, reagent concentration and diverse ions. Experimental data have been analyzed graphically to determine the stoichiometry of the extracted species. It was found that the extraction of iridium(III) proceeds by an anion exchange mechanism and transforms into the extracted species [RR"NH₂ ⁺Ir(C₃H₂O₄)₂ ^–]_org. The method is simple, rapid, and selective and has been devised for the sequential separation of iridium(III) from rhodium(III), not only from each other, but also from other accompanying Platinum Group Metals (PGMs), Au(III), and base metals.     

Extraction of Nd(III), Tb(III) and Lu(III) with picrolonic acid in methylisobutylketone

The extraction of Nd(III), Tb(III) and Lu(III) as representatives of lanthanide(III) ions with picrolonic acid (HPA) in methylisobutylketone (MIBK) has been studied from pH 1-2 buffer solutions. The composition of the organic species formed in the organic phase after extraction has been determined by slope analysis to be M(PA)₃ [M = Nd(III), Tb(III) and Lu(III)]. The equilibrium constant values, log k _ex This revised version was published online in July 2006 with corrections to the Cover Date.     

Selective Second Order Derivative Spectrophotometric Method for the Determination of Gallium(III) in Presence of Large Excess of Indium(III)

Abstract

A simple, sensitive, and selective second order derivative spectrophotometric method is proposed for the determination of microgram quantities of gallium(III) especially in presence of large excess of indium(III). Ga(III) reacts with 2‐hydroxy‐3‐methoxy benzaldehyde isonicotinoylhydrazone (HMBAINH) chromogene forming an intense greenish yellow coloured soluble complex in acidic buffers and in presence of 0.2% of triton X‐100. The complex showed maximum absorption at 405 nm and at pH 5.0, where the reagent has negligible absorbance. A second order derivative spectrum of the complex solution showed maximum derivative amplitude at 415 nm and again at 460 nm with a zero cross at 442 nm. Beer's law was obeyed in the concentration range 0.036–1.533 µg/ml and 0.070–1.533 µg/ml of Ga(III) at 415 nm and 460 nm, respectively. However, at 404 nm In(III)‐HMBAINH complex showed zero amplitude in the second order derivative spectrum where Ga(III)‐HMBAINH obeyed Beer's law in the range of 0.070–1.394 µg/ml. This allows determination of Ga(III) in presence of large excess of In(III) by second order derivative spectrophotometry. The tolerance limits of other diverse ions and other analytical parameters were also evaluated. The method was applied for the determination of gallium in some synthetic mixtures containing indium.     

Development of liquid-liquid extraction and separation method for ruthenium(III) with 2-octylaminopyridine from succinate media: Analysis of catalysts

Ruthenium(III) has been efficiently extracted from 0.05 M sodium succinate at pH 9.5 by 2-octylaminopyridine in xylene and stripped with aqueous 10% (w/v) thiourea solution and determined spectrophotometrically. Various parameters viz., pH, weak acid concentration, reagent concentration, stripping agents, contact time, loading capacity, aq.: org. volume ratio, solvent has been thoroughly investigated for quantitative extraction of ruthenium(III). The utility of method was analyzed by separating the ruthenium(III) from binary mixture along with the base metals like Cu(II), Ag(I), Fe(II), Co(II), Bi(III), Zn(II), Ni(II), Se(IV), Te(IV), Al(III) and Hg(II) as well as platinum group metals (PGMs). Ruthenium(III) was also separated from ternary mixtures like Os(VIII), Pd(II); Pd(II), Pt(IV); Pd(II), Au(III); Pd(II), Cu(II); Fe(II), Cu(II); Ni(II), Cu(II); Co(II), Ni(II); Se(IV), Te(IV); Rh(III), Pd(II); Fe(III), Os(VIII). The stoichiometry 1: 2: 1 (metal: succinate: extractant) of the proposed complex was determined by slope analysis method by plotting graph of logD _[Ru(III)] versus logC _[2-OAP] and logD _[Ru(III)] versus logC _[succinate]. The interference of various cations and anions has been studied in detail and the statistical evaluations of the experimental results are reported. The method was successfully applied for the analysis of ruthenium in various catalysts, synthetic mixtures corresponding to the composition of alloys and minerals.     

Electrochemical and electrocatalytic properties of meso-triphenylcorrole and its complexes with Mn(III), Co(III), Cu(III), and Zn(II)

The method of cyclic voltammetry (CV) was used to compare electrochemical and electrocatalytic properties of meso-triphenylcorrole [H₃(ms-Ph)₃Cor] and also its complexes with Mn(III), Co(III), Cu(III), and Zn(II) in 0.1M KOH. Metal-localized redox transitions are detected in the complexes of Mn (III ?? IV) and (III ?? II), Co (III ?? II), Cu (III ?? II). It is shown that the manganese complex features most effective catalytic properties in the reaction of molecular oxygen electroreduction.     

Kinetics of reduction of hydroxycuprate(III) in KOH solution

The solution of an unstable copper(III) complex, hydroxycuprate(III) i.e. Cu(OH)^– ₄, has been obtained by oxidising a copper anode in 0.5–3 M KOH solution. The kinetics of the copper(III) reduction in KOH solution has been studied spectrophotometrically and is first order with respect to copper(III), and the pseudo-first order rate constant increases as the KOH concentration increases. The kinetic data is explained by a scheme according to which a Cu^III intermediate, in equilibrium with Cu(OH)^– ₄, reacts with OH^–. On the basis of the kinetic data, the molar absorptivity of the Cu(OH)^– ₄ solution has been determined.     

Synthesis and photophysical properties of new Ln(III) (Ln = Eu(III), Gd(III), or Tb(III)) complexes of 1-amidino-O-methylurea

Three new solid lanthanide(III) complexes, [Ln(1-AMUH)₃] · (NO₃)₃ (1-AMUH = 1-amidino-O-methylurea; Ln = Eu(III), Gd(III), or Tb(III)) were synthesised and characterised by elemental analysis, infrared spectra, magnetic moment measurement, and electron paramagnetic resonance (EPR) spectra for Gd(III) complex. The formation of lanthanide(III) complexes is confirmed by the spectroscopic studies. The photophysical properties of Gd(III), Eu(III), and Tb(III) complexes in solid state were investigated. The Tb(III) complex exhibits the strongest green emission at 543 nm and the Eu(III) complex shows a red emission at 615 nm while the Gd(III) complex shows a weak emission band at 303 nm. Under excitation with UV light, these complexes exhibited an emission characteristic of central metal ions. The powder EPR spectrum of the Gd(III) complex at 300 K exhibits a single broad band with g = 2.025. The bi-exponential nature of the decay lifetime curve is observed in the Eu(III) and Tb(III) complexes. The results reveal them to have potential as luminescent materials.     

Liquid-liquid extraction of iron(III) and gallium(III) with macrocyclic Schiff bases containing bisphenol A subunits

The quantitative extraction of iron(III) and gallium(III) was investigated with the recently synthesized macrocyclic Schiff base containing bisphenol A subunits. The phenol groups in the Schiff base moiety led to a large increase in the percent extraction of trivalent metal ions. The substitution of methoxy groups for phenolic OH ligands resulted in a marked decrease in the extractability of metal ions, and no iron(III) was extracted. The corresponding acyclic Schiff base was found to have a reasonable reactivity toward metal ions and a better solubility in organic solvents. The iron(III) and gallium(III) complexes with macrocyclic and acyclic Schiff bases were quantitatively extracted into nitrobenzene without the presence of bulky counter anions. A single extraction gave a good separation of iron(III) from iron(II) in the mole ratios 4:1 to 1:3. The red iron(III) complexes can be used for the extraction-spectrophotometric determination of iron(III). The apparent molar absorptivity at 518 nm is 5.43 × 10³lmol⁻¹ cm⁻¹.     

Studies on the extraction and spectrophotometric determination of Ni(II), Fe(II), Fe(III) and V(IV) with bis(4-hydroxypent-2-ylidene)diaminoethane

The extraction of Ni(II), Fe(II), Fe(III) and V(IV) with bis(4-hydroxypent-2-ylidene)-diaminoethane from various acids and buffer solutions has been studied. The golden yellow Fe(II) and wine-red Fe(III) complexes have maximum absorption at 445 and 435 nm respectively, and the yellow-green Ni(II) chelate shows two maxima, at 373 and 560 nm. The blue-green V(IV) chelate also has two maxima, at 580 and 660 nm. These characteristics can be used for the determination of these species. Iron, nickel and vanadium have been separated and determined in the presence of one another and of many other elements.     

Zero-Order and Third-Derivative Spectrophotometric Determination of Iron(III) with 4-(2-Pyridylazo)-Resorcinol in the Presence of N-Hexadecylpyridinium Chloride

Abstract

The complex formation reaction between iron(III) and 4-(2-pyridylazo) resorcinol(PAR) in the presence of various water soluble surfactants((N-hexadecylpyridinium chloride (HPC), poly(vinylalcohol)(PVA), sodium dodecylsulfate(SDS), sodium N-lauroylsarcosine(SL)) alone or in combination at weakly acidic media was systematically investigated. An improved and more sensitive spectrophotometric method for the determination of iron was proposed by zero-order and third-derivative spectrophotometry using the PAR-iron(III)-HPC ternary complex system at about pH 5.2. The calibration curve was rectilinear in the ranges of 0 – 15.0 μg iron(III) in a final 10-ml on the zero-order spectrophotometry. Also, upon the third-derivative spectrophotometry, Beer's law was obeyed in the range of 0 – 8.0 μg iron(III)/10 ml by measuring the distance between the absorbance peak(λ₁ = 527 nm) and the valley (λ₂ = 560 nm). The apparent molar absorptivity was 4.8 × 10⁴ 1 mol^?1 cm^?1 in zero-order spectrophotometry, and 1.36 × 10⁵ mol^?1 cm^?1 in third-derivative spectrophotometry. The effect of foreign ions was decreased within ½ – ¼-fold in comparison with the method in the presence of PVA without HPC. Especially, the third-derivative spectrophotometric method was sensitive and selective, and made possible to assay mixed sample solution containing iron(III) and copper(II), etc.