Separation and concentration processes of solutions of Co(II), Ni(II), Cr(III), Fe(III) and Mn(II) by extraction with toluene-dissolved rosin

The extraction and stripping of Co(II), Ni(II), Cr(III) and Fe(III) from aqueous solutions by rosin dissolved in toluene has been investigated. Results obtained show that rosin is better extractant than abietic or n-lauric acids under comparable conditions. From these results, and the data of Mn(II) solvent extraction studied previously under the same conditions, a separation and concentration process for these five cations in aqueous solutions has been designed. Saturated solutions of Fe(III), Cr(III), Mn(II) and finally Co(II) and Ni(II) have been obtained successively by extraction and stripping, by addition of ammonium hydroxide to obtain the appropriate pH value, and by modifying adequately the organic phase/aqueous phase volume ratio.     

LIQUID-LIQUID EXTRACTION OF GOLD(III) AND ITS SEPARATION OVER COPPER(II), IRON(III), AND ZINC(II) USING THIOUREA DERIVATIVES FROM CHLORIDE MEDIA

ABSTRACT

Selective liquid-liquid extraction of Au(III) from aqueous chloride media (1 mol/L NaCl) into cumene by thiourea derivatives namely 2a-c (N-thiocarbamoylbenzamidine derivatives), 3a-f (N-benzoylthiourea derivatives) has been investigated in detail. Marked differences in the metal extraction are noted using these organic compounds with respect to their structural variation. The extraction behaviour of Au(III) with extractants 2a-c and 3a-f followed the order : 2b> 2a>2c and 3e≈ 3c≈ 3d >3a >3f≈3b, respectively. The organic reagent 2a and 3c were selected for further detailed studies owing to their better strippability behaviour. Optimum conditions such as structure of the organic extractant, aqueous phase pH, diluent, time of equilibration, metal concentration, extractant concentration, effect of other metal cations were established for extraction separation of Au(III). Experimental data have been treated graphically and numerically by means of the computer programme LETAGROP-DISTR, and can be explained by assuming the formation of the species AuCl₃L and AuCl₃L₂ for 2a-c and AuCl₃L₂ for 3a-f derivatives. The lack of interference from even appreciable amounts of possible base metals such as Cu(II), Zn(II) and Fe(III) may be considered an outstanding advantage of the method for separation of gold from these metals using 2a and 3c.     

Selective extraction of In(III), Ga(III) and Zn(II) using a novel extractant with phenylphosphinic acid

A new extractant, [N,N-di(2-ethylhexyl)amino]methylphenylphosphinic acid (DEAPP), was synthesized to de-velop the mutual separation techniques of In(III), Ga(III) and Zn(II). The extraction selectivity for In(III), Ga(I I) and Zn(II) with DEAPP was higher than that of the commercial phosphorus acid extractants such as D2EHPA and PC-88A. The extraction selectivity for metal ions in 1 mol·L?1 aqueous ammonium nitrate solution with DEAPP was in the following order:In(III) N Ga(III) N Zn(II). These selective extraction behaviors indicate that the amino moiety of DEAPP plays an important role in the mutual separation of In(III), Ga(III) and Zn(II). The extraction equilibria of In(I I), Ga(II ) and Zn(II) with DEAPP (=HR) were expressed by the following reactions:In3++2eHRT2?InR3eHRT+3H+, Ga3++1.5eHRT2+NO3??GaR2eHRTeNO3T+2H+, and Zn2++2eHRT2?ZnR2eHRT 2 + 2H+. The extraction equilibrium constants of In(III), Ga(III) and Zn(II) with DEAPP were determined to be Kex,M=1.7 × 104 [dm3·mol?1], 4.17 [(dm3·mol?1)0.5], and 1.55 x 10?2 [–], respectively.     

Separation of Mercury(II) as Chloride from Zinc(II), Cadmium(II), Gold(III), and Thallium(III) by Extraction in High-Molecular-Weight Amines

Abstract

The extraction behavior of Zn(II), Cd(II), Hg(II), Au(III), and Tl(III) has been studied at different HCl molarities in some commercially available liquid anion exchangers. The effect of such variables as the type of amine, molarity of HCl, amine concentration, and organic diluent on extraction has been explored to suggest the best conditions of separation of Hg(II) from Zn(II), Cd(II), Au(III), and Tl(III).     

Selective transport of cobalt (II) from ammoniacal solutions containing cobalt (II) and nickel (II) by emulsion liquid membranes using 8-hydroxyquinoline

The selective transport of cobalt (II) from ammoniacal solutions containing nickel (II) and cobalt (II) by emulsion liquid membranes (ELMs) using 8-hydroxyquinoline (8-HQ) as extractant has been presented. Membrane solution consists of a diluent (kerosene), a surfactant (ECA 4360J), and an extractant (8-HQ). Very dilute sulphuric solution buffered at pH 5.0 has been used as a stripping solution. The ammoniacal feed solution pH was adjusted to 9.0 with hydrochloric acid. The important variables governing the permeation of cobalt (II) have been studied. These variables are membrane composition, pH of the feed solution, cobalt (II) and nickel (II) concentrations of the feed solution, stirring speed, surfactant concentration, extractant concentration, complexing agent concentration and pH of the stripping solution, and phase ratio. After the optimum conditions had been determined, it was possible to selectively transport 95.0% of cobalt (II) from ammoniacal feed solution containing Co²⁺ and Ni²⁺ ions. The separation factors of cobalt (II) with respect to nickel (II), based on initial feed concentration, have experimentally found to be of as high as 31 for equimolar Co(II)–Ni(II) feed solution.     

The Application of 2,6-Bis(4-Methoxybenzoyl)-Diaminopyridine in Solvent Extraction and Polymer Membrane Separation for the Recovery of Au(III), Ag(I), Pd(II) and Pt(II) Ions from Aqueous Solutions

The work describes the results of the first application of 2,6-bis(4-methoxybenzoyl)-diaminopyridine (L) for the recovery of noble metal ions (Au(III), Ag(I), Pd(II), Pt(II)) from aqueous solutions using two different separation processes: dynamic (classic solvent extraction) and static (polymer membranes). The stability constants of the complexes formed by the L with noble metal ions were determined using the spectrophotometry method. The results of the performed experiments clearly show that 2,6-bis(4-methoxybenzoyl)-diaminopyridine is an excellent extractant, as the recovery was over 99% for all studied noble metal ions. The efficiency of 2,6-bis(4-methoxybenzoyl)-diaminopyridine as a carrier in polymer membranes after 24 h of sorption was lower; the percentage of metal ions removal from the solutions (%R_s) decreased in following order: Ag(I) (94.89%) > Au(III) (63.46%) > Pt(II) (38.99%) > Pd(II) (23.82%). The results of the desorption processes carried out showed that the highest percentage of recovery was observed for gold and silver ions (over 96%) after 48 h. The results presented in this study indicate the potential practical applicability of 2,6-bis(4-methoxybenzoyl)-diaminopyridine in the solvent extraction and polymer membrane separation of noble metal ions from aqueous solutions (e.g., obtained as a result of WEEE leaching or industrial wastewater).     

Extraction and separation of molybdenum(VI) from acidic media by fatty hydrazides

BACKGROUND: The increasing demand for molybdenum has encouraged the development of low‐cost and environmentally friendly extractants to recycle and recover this metal. In the present study, solvent extraction of Mo(VI) from acidic media using a mixture of fatty hydrazides synthesised from palm olein as the extractant was carried out. The effects of various parameters such as acid, diluent, contact time, extractant concentration, metal ion concentration and stripping agent and the separation of Mo(VI) from other metal ions such as Co(II), Ni(II), Al(III) and Mn(II) were investigated. RESULTS: It was found that the extraction of Mo(VI) into the organic phase involved the formation of 1:3 complexes. Mo(VI) was successfully separated from commonly associated metal ions such as Ni(II), Co(II), Al(III) and Mn(II). Mo(VI) stripping from the loaded organic phase was studied using different acidic and alkaline solutions and was found to be optimal with ammonium hydroxide solution. CONCLUSION: These results are useful for the development of a method to recover Mo(VI) from acidic media utilising fatty hydrazides as the extractant. Copyright © 2008 Society of Chemical Industry     

Extraction Behavior of Zinc(II), Cadmium(II), Mercury(II), Indium(III), and Thallium(III) as Thiocyanates in High-Molecular-Weight Amines and Some Mutual Binary Separations

Abstract

The extraction behavior of Zn(II), Cd(II), Hg(II), In(III), and Tl(III) has been studied at different NH₄CNS molarities in some commercially available liquid anion exchangers. The effect of such variables as the type of amine, molarity of NH₄CNS, and pH of aqueous phase and organic diluent on extraction has been explored to achieve the best conditions of some mutual binary separations of analytical and radiochemical interest.     

Solvent-Extraction Behavior of Cobalt(II), Nickel(II), Copper(II), and Palladium(II) with Tri-n-butylphosphate

Abstract

A systematic study of the extraction behavior of cobalt(II), nickel(II), copper(II), and palladium(II) with TBP from thiocyanate system in various ranges of acid concentrations has been performed. The thiocyanate medium leads to enhanced extractions in all these cases compared to those in the previously used chloride medium. For palladium, the chloride and nitrate systems have been critically examined. Sixty-two per cent extraction occurs from 4 M hydrochloric acid using 100% TBP in a single run and the extraction becomes quantitative (>99%) after four successive equilibrations. A simpler method has been proposed for rapid extraction of palladium(II) as the thiocyanate complex. Quantitative extraction occurs in the presence of 1.2% thiocyanate solution from 0.5 to 2 M hydrochloric acid (initial) up to pH 8.0. The extractable species of cobalt(II), nickel(II), copper(II), and palladium(II) from thiocyanate medium are probably similar and of the type [M(CNS)₄]^2? [K·TBP·3H₂O]₂ ⁺ (buffer solution) and [M(CNS)₄]^2? [H·TBP·3H₂O]⁺ ₂ (acid solution). A simple extraction scheme has been worked out for the separation of palladium(II) from iron(III), cobalt(II), nickel, manganese(II), copper(II), and platinum.     

Solvent Extraction Separation of Beryllium(ll) from Aluminum(lll) by Cyanex 921 (TOPO)

ABSTRACT

Cyanex 921, a neutral extractant, has been used for the extraction of beryllium(II)from basic media and employed for the separation of beryllium(II) in the presence of aluminum(III). Cyanex 921 diluted in cyclohexane extracted beryllium(II) in the 8–10 pH range and aluminum(III) between 4–5 pH. The selectivity of beryllium(II) over aluminum(III) was high in the 8–10 pH range. The extracted beryllium(II) was stripped with 0 M NaOH without any significant loss of the ligand while loaded aluminum(III) was stripped with 2 M HC1. The extractability of beryllium(II) and aluminum(III) was also studied separately as a function of pH, temperature, equilibration time, and stripping ability with NaOH, KOH, HCI, HNO₃, H₂SO₄, and HCIO₄. Based on these results, a sequential method was developed for the separation of beryllium(II) from aluminum(III).     

Selective Separation of Scandium(III) and Yttrium(III) from other Rare Earth Elements using Cyanex302 as an Extractant

Abstract

Liquid‐liquid extraction and selective separation of scandium(III) and yttrium(III) with Cyanex302 (bis(2,4,4‐trimethylpentyl)monothiophosphinic acid) has been carried out by controlling the aqueous phase pH. Scandium(III) and yttrium(III) were completely recovered from the organic phase using 5.0 M and 4.0 M nitric acid respectively and determined spectrophotometrically as their complexes with Arsenazo(III). The influence of extractant concentration, equilibration time, nature of diluents, stripping agents, and diverse ions on the extraction of scandium(III) and yttrium(III) was investigated. The extractability of scandium(III), yttrium(III), and other rare earth elements was exploited for sequential separation of scandium(III)‐yttrium(III)‐lanthanum(III) and other rare earth elements viz. lanthanum(III), cerium(IV), praseodymium(III), neodymium(III), gadolinium(III), dysprosium(III), and ytterbium(III) in binary mixtures. The method presented is simple and rapid for isolation of scandium(III) and yttrium(III) from associated elements and has been successfully applied for their selective separation from complex matrices of USGS standard soil GXR‐2 and Japanese standard stream sediment sample Jsd‐3.     

The Effect of Degree of Impregnation in Amberlite Resins with Organophosphorous Extractants for Y(III), La(III), Ce(III), Th(IV) and U(VI) Ions

Abstract

Background: The sorption of Y(III), La(III), Ce(III), U(VI) and Th(IV) ions with solvent impregnated resins using diphenylphosphate (DPP), and diphenylphosphinic acid (DPPA) as extractant and Amberlite XAD 16 and Amberlite XAD 2000 as a polymeric support has been studied. The impregnated resins containing various amounts of extractants (10/90, 20/80, 50/50, 60/40) have been prepared by a dry method. The effects of pH, types of extractant, extractant content, surface area of polymeric support and contact time have been investigated by batch method.

Results: The impregnation for DPP on XAD‐16 and XAD‐2000 was 111 and 46% at 60/40 extractant/resin mass ratio, respectively. The impregnation of DPPA at all ratios on both resins was found constant and lower than DPP. The sorption percentage of studied metal ions was within 90‐99% for DPP and DPPA on both resins after 20/80 extractant/resin mass ratio.

Conclusions: The sorption of DPP on Amberlite XAD 16 and XAD 2000 resins is rather more than DPPA. It could be seen that 20/80 extractant/resin mass ratio is generally adequate for single metal analysis where 60/40 could be suitable for multi‐metal analysis.     

LIQUID-LIQUID EXTRACTION OF Ag(I), Hg(II), Au(III) AND Pd(II) BY SOME OLIGOTHIA MACROCYCLIC LIGANDS INCORPORATING AROMATIC AND HETEROAROMATIC SUBUNITS*

ABSTRACT

A series of hydrophobic tri- to hexa-dentate sulfur containing macrocyclic ligands incorporating aromatic and heteroaromatic subunits have been studied with respect to their extraction properties toward Ag(I), Hg(II), Au(III), and Pd(II) in aqueous//organic systems. The stoichiometry of extracted species and their extraction constants have been determined. The different ligands are compared with structure related open-chain compounds. The influence of substitution, solvent, and anion on the extraction equilibrium is also discussed providing a basis for future design of selective extractants and for die development of improved separation methods. The extractability of the various metal ions strongly depends on the nature and the number of donor atoms of the corresponding ligands and on the properties of the metal ion itself. In some cases, simple open-chain ligands show extraction properties comparable to the present macrocycles. A trithia crown with incorporated benzo subunit highly prefers Ag(I) to Hg(II). Furthermore a distinct selectivity for Au(ni) and Hg(II) over Pd(II) with pyridine substituted macrocycles was found.     

Separation of Co(II) and Ni(II) from thiocyanate media by hollow fiber supported liquid membrane containing Alamine300 as carrier — investigation on polarity of diluent and membrane stability

The separation of cobalt(II) and nickel(II) ions by HFSLM has been presented. The feed solution is 0.5M thiocyanate containing 300 ppm each of cobalt(II) and nickel(II) ions, whereas extractant is Alamine300 and the stripping solution is ammonia. Cobalt(II) is more preferable with Alamine300 than nickel(II). The effects of pH, Alamine300 concentration and ammonia concentration were investigated. Seven diluents were used: hexane, decanol, chlorobenzene, benzene, dichloromethane, ethylene dichloride and chloroform with different polarity indexes, from 0.1–4.1. Nickel(II) ion which is unpreferable with Alamine300 was used as a tracer to determine the membrane stability. The polarity of the diluents was found to be the main factor influencing the extraction performance and stability of a liquid membrane. The decreasing of polarity of the diluent can prolong the membrane stability, but the percentages of extraction and stripping decreased. The longest lifetime, 200 minutes, was obtained by using hexane as a diluent with the polarity index of 0.1.     

Extraction of U(VI), Th(IV), and Lanthanides(III) from Nitric Acid Solutions with CMPO-Functionalized Ionic Liquid in Molecular Diluents

The extraction of microquantities of U(VI), Th(IV), and lanthanides(III) from nitric acid solutions with CMPO-functionalized ionic liquid 1-[3[[(diphenylphosphinyl)acetyl]amino]propyl]-3-tetradecyl-1H-imidazol-3-ium hexafluorophosphate, CMPO-FIL(I) in molecular organic diluents has been studied. The effect of HNO₃ concentration in the aqueous phase and that of extractant concentration in the organic phase on the extraction of metal ions is considered. The stoichiometry of the extracted complexes was determined. CMPO-FIL(I) demonstrates greater extraction ability towards Ln(III) than its neutral CMPO analog, diphenylphosphorylacetic acid N-nonylamide. This inner synergistic effect increases with a decreasing organic diluent polarity. The partition of CMPO-FIL(I) between the equilibrium organic and aqueous phases is the dominant factor governing the extractability of Ln(III) ions in the extraction system.     

Selective separation and concentration of Pd(II) from Fe(III), Co(II), Ni(II), and Cu(II) ions using thiourea‐formaldehyde resin

Thiourea‐formaldehyde (TUF), a well‐known chelating resin, has been synthesized and it was used in the adsorption, selective separation, and concentration of Pd(II) ions from Fe(III), Co(II) Ni(II), and Cu(II) base metal ions. The composition of the synthesized resin was determined by elemental analysis. The effect of initial acidity/pH and the adsorption capacity for Pd(II) ions were studied by batch technique. The adsorption and separation of Pd(II) were then examined by column technique. FTIR spectra and SEM/EDS analysis were also recorded before and after the adsorption of Pd(II). The optimum pH was found to be 4 for the adsorption. The adsorption data fitted well to the Langmuir isotherm. The maximum adsorption capacity of the TUF resin for Pd(II) ions was found to be 31.85 mg g⁻¹ (0.300 mmol g⁻¹). Chelating mechanism was effective in the adsorption. Pd(II) ions could be separated efficiently from Fe(III), Cu(II), Ni(II), and Co(II) ions using TUF resin. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

SOLVENT IMPREGNATED RESINS CONTAINING DI(2-ETHYL-HEXYL)PHOSPHORIC ACID.II. STUDY OF THE DISTRIBUTION EQUILIBRIA OF Zn(II), Cu(II) AND Cd(II).

ABSTRACT

The extraction of Zn(II), Cu(II) and Cd(II) from nitrate solutions at 0.1 M ionic strength by impregnated resins containing di(2-ethylhexyl)phosphoric acid has been studied at 25 °C.

The distribution coefficient was determined as a function of both pH and extractant concentration in the resin phase. The data were analyzed graphically using the slope analysis method, and numerically using the program LETAGROP-DISTR. The composition of the extracted species in the resin phase has been determined.

Analysis of the results showed that the extraction of these metal ions can be explained assuming the formation of metal complexes in the resin phase with a general composition ML₂(HL) _q where q takes different values depending on the metal. An extraction reaction is proposed and the extraction constants of these species are given.

Finally, a comparison between the extraction of Zn(II), Cu(II) and Cd(II) by di(2-ethylhexyl)phosphoric acid into Amberlite XAD2 and the extraction using organic solvents has been made.     

EXTRACTION AND SEPARATION OF HEAVY RARE EARTH(III) WITH EXTRACTION RESIN CONTAINING DI(2,4,4-TRIMETHYL PENTYL) PHOSPHINIC ACID (CYANEX 272)

ABSTRACT

Extraction resins, of the type of Levextrel, (which is a collective term for styrene/divinylbenzene based copolymers of predominantly macroporous structure that contain a selective extractant) are important for the recovery and separation of metal ions, as they combine features of solvent extraction and ion exchange resins. This paper presents the results of the adsorption of heavy rare earth ions (Ho(III), Er(III), Tm(III), Yb(III), Lu(III) and Y(II1)) from hydrochloric acid solutions at 0.2 mol/L ionic strength and 50°C by the extraction resin containing di (2,4,4-trimethyl pentyl) phosphinic acid (Cyanex 272) and the chromatographic separation of (Er(III), Tm(III) and Yb(III)). Technological separation products, with purity and yield of Tm₂O3 >99.97%, >80%; Er₂O₃ >99.9%, >94% and Yb₂O₃ >99.8%, >80% respectively, have been obtained from a feed having the composition Tm₂O₃ 60%, Er₂O₃ 10%, and Yb₂O₃ 3%, the others 27%.

The distribution coefficients, extraction equilibrium constants and separation factors have been determined as a function of acidity, loading of the resin and rare earths, flow rates and column ratios. The resolutions and efficiencies of separation of Er/Tm/Yb each other have been calculated. The stoichiometry of the extraction of rare earth ions has been suggested as well.     

SOLVENT EXTRACTION OF SCANDIUM(III), YTTRIUM(III), LANTHANIDES(III), ANDDIVALENT METAL IONS WITH SEC -NONYLPHENOXY ACETIC ACID

ABSTRACT

Such physicochemical properties of sec-nonylphenoxy acetic acid (CA-100) as the solubility in water, acid dissociation constant in water, dimerization constant in heptane, and distribution constant in organic solvent-water were measured by two-phase titration. The extraction behaviors of scandium (III), yttrium (III), lanthanides (III), and divalent metal ions from hydrochloric acid solutions with CA-100 in heptane have been investigated, and the possibilities of separating scandium (yttrium) from lanthanides and divalent metal ions have been carefully discussed. The stoichiometries of the extracted metal complexes were investigated by the slope-analysis technique. The effect of the nature of diluent on the extraction of yttrium (III) with CA-100 has been studied and correlated with the dielectric constant.     

Highly selective separation and recovery of Pd(II) from the automotive catalyst residue with the thiocarbamoyl substituted azothiacalix[4]arene derivative

New ligand, namely, 5, 11, 17, 23-tetrakis-((p-chlorophenyl) azo)-25,26,27,28-tetrakis ((dimethylthio carbamoyl)oxy) thiacalix[4]arene (CADTTCA), has been investigated for separation and recovery of Pd(II) through solvent extraction technique. Experimental parameters such as contact time, diluents, effect of H⁺ and Cl^? concentration, and acid durability have been thoroughly investigated. The loading capacity toward Pd(II) was determined to be 113 mg/L using 0.25 mM CADTTCA. The extractant showed high selectivity and extractability for Pd(II) than the other metal ions present in automotive catalyst residue (ACR) solution containing platinum group (PGMs) metal ions (i.e., Pd(II), Pt(IV), Rh(II), La(III), Al(III) and Ce(III)). The recovery percentage of Pd(II) was 98% after five extraction-scrubbing-stripping cycles. The probable extraction mechanisms were established through the FT-IR spectral analysis.