Solvent Extraction Of Cu Research Articles

Multivariate optimization of solvent extraction with 1,1,1-trifluoroacetylacetonates for the determination of total and labile Cu and Fe in river surface water by flame atomic absorption spectrometry

A procedure for simultaneous solvent extraction of Cu(II) and Fe(III) from river surface waters as diethyldithiocarbamates (DDC) 1,1,1-trifluoroacetylacetonates into isobutyl methyl ketone (IBMK) has been developed prior to their determination by flame atomic absorption spectrometry. Experimental design approaches were used in order to obtain the best compromise conditions for simultaneous solvent extraction. Variables such as pH, sodium DDC or 1,1,1-trifluoro-2,4-pentanodione (H(TFA)) concentrations, reaction time, IBMK volume and extraction time have been optimized. First, Plackett–Burman designs involving 13 experiments and 2 replicates were used as screening designs to determine which variables were significant. DDC or H(TFA) concentration, as well as pH and IBMK volume were found statistically significant and they were finally optimized by applying a central composite design (15 experiments and 2 replicates). Optimum values for these variables were selected for compromise extraction conditions of Cu(II) and Fe(III) species. An optimum pH of 5.3 was chosen for Cu–H(TFA) and Fe–H(TFA) formation with an optimum H(TFA) concentration of 0.20% (m/v). The optimum IBMK volume for extraction was 8 ml, allowing a pre-concentration factor of 10. A microwave-assisted peroxydisulfate oxidation was used to break down the metal–organic matter complexes in river surface waters in order to assess the total Cu and Fe contents. Applying the experimental design approach, optimum conditions was an irradiation for 5.0 min at a microwave power of 500 W using 0.5 g of ammonium peroxydisulfate. The method was applied to determine total Cu and Fe contents and also labile Cu(II) and Fe(III) contents in several river surface water samples.

Non-dispersive solvent extraction of Cu(II) by LIX 973N from ammoniacal/ammonium carbonate aqueous solutions

The non-dispersive solvent extraction (NDSX) of copper from aqueous ammoniacal/ammonium carbonate medium with LIX 973N using a microporous hydrophobic polypropylene hollow fiber contactor is reported. The influence of aqueous pH, ammonium carbonate concentration, copper concentration, extractant concentration, organic phase volume on relative concentration decrease of copper was investigated as a function of time. These experimental variables barely influenced the decrease in the relative concentration, whereas the module configuration (counter or co-current) influences copper extraction. The relative concentration can be well described as an exponential function of time. Copper stripping is accomplished using sulphuric acid solution.

Preconcentration and separation of copper (II) with solvent extraction using N, N′-bis(2-hydroxy-5-bromo-benzyl)1,2 diaminopropane

Preconcentration and separation with solvent extraction of Cu(II) from aqueous solution using N, N′-bis(2-hydroxy-5-bromo-benzyl)1,2 diaminopropane (H 2L) as the new extractant has been studied. Separation of Cu(II) from other metal ions such as Cd(II), Ni(II), Zn(II), Pb(II), Cr(III), Co(II) and Mn(II) at aqueous solutions of various pH values and complexing agent H 2L, has been described. The possible extraction mechanism and the compositions of the extracted species have been determined. The separation factors for these metals using this reagent are reported while efficient methods for the separation of Cu(II) from other metal ions are proposed. From the loaded organic phase, Cu(II) stripping was carried out in one stage with different mineral acid solutions. The stripping efficiency was found to be quantitative in case of HNO 3 and HCl. From quantitative evaluation of the extraction equilibrium data, it has been deduced that the complex extracted is the simple 1:1 chelate, CuL. The extraction constant has a value of log K ex=−4.05±0.04.

Solvent extraction of Cu(II) by LIX 54-100 and its application to a solid supported liquid membrane system

Solvent extraction of Cu(II) by LIX 54-100 and its application to a solid supported liquid membrane system

Extraction and polarography of copper(II)-bis (acetylacetone) ethylendiimine in dichloromethane: use of differential pulse method for the determination of copper in steel

The voltammetric characteristics of copper(II)-bis(acetylacetone) ethylendiimine, Cu(II)-BAE, at the mercury electrode in the presence of two different types of supporting electrolytes have been studied in dichloromethane. A two-electron irreversible nature for the reduction process of Cu(II)-BAE complex was observed. Preceded by a solvent extraction of Cu(II)-BAE in dichloromethane, differential pulse (DP) polarography was used for the determination of copper. The calibration graph was linear over the concentration range 1–30 μM of Cu(II); the detection limit of the method was approximately 0.8 μM. Any interference from other ions, even those extractable with dichloromethane solution of BAE, was not observed. The proposed DP method is highly selective and has been successfully applied to the determination of copper in steel.

Differential pulse anodic stripping voltammetry of copper in dichloromethane: application to the analysis of human hair

The voltammetric characteristics of copper(II)–bis(acetylacetone)ethylenediimine (Cu(II)–BAE) complex in dichloromethane at the mercury electrode are investigated. Anodic stripping voltammetry (ASV) for the determination of trace-copper was developed in dichloromethane, using the differential pulse technique to strip the amalgamated copper from the hanging mercury drop electrode (HMDE). The experimental variables such as scan rate of electrode potential, deposition potential, deposition time and stirring speed of the solution were optimized. The linear range of calibration graph and the detection limit were 5 × 10 −8–10 −6 M and 1.6 × 10 −8 M of Cu(II), respectively. Preceded by wet ashing of the sample and solvent extraction of Cu(II)–BAE complex into dichloromethane, the method was used for the determination of copper in human hair as a typical example of application.

Electro-assisted solvent extraction of Cu 2+, Ni 2+ and Cd 2+

A novel separation method, i.e. electro-assisted solvent extraction, based on the principles of two-phase electrochemistry, has been demonstrated for the successful separation of Ni 2+, Cu 2+ and Cd 2+ ions. 2-Heptanone has been used as the organic solvent for the transfer of Ni 2+, Cu 2+ and Cd 2+ facilitated by 2,2′;6′,2″-terpyridine. It is shown that extraction efficiency depends on the concentration ratio of ligand to metal ion and importantly, on the applied interfacial potential difference. It was found that Ni 2+ (not Cd 2+ or Cu 2+) extraction is suppressed in the presence of Mg 2+ ion due to competitive complexation.

Equilibrium Analysis of Aggregation Behavior in the Solvent Extraction of Cu(II) from Sulfuric Acid by Didodecylnaphthalene Sulfonic Acid

Abstract By use of the principles of equilibrium analysis, the liquid-liquid cation exchange of Cu(II) from aqueous sulfuric acid at 25°C by didodecylnaphthalenesulfonic acid (HDDNS) in toluene may be understood in terms of small hydrated aggregated species in the organic phase. Extraction data have been measured as a function of organic-phase HDDNS molarity (1.0 × 10−4 to 1.0 × 10−1), aqueous copper(II) sulfate molarity (1.2 × 10−8 to 1.3 × 10−2), and aqueous sulfuric acid molarity (0.03 to 6.0). Graphical analysis of linear regions of the data support a model in which organic-phase aggregates of HDDNS function by cation exchange to incorporate Cu(II) ions with no apparent change in aggregation number at low loading. Supporting FTIR spectra and water-content measurements of HDDNS solutions in toluene show that the HDDNS aggregates are highly hydrated. By use of the computer program SXLSQA, a comprehensive equilibrium model was developed with inclusion of activity effects. Aqueous-phase activity coefficie...

Prediction of Cu(II) Solvent Extraction Behavior with Hydroxyoxime in the Presence of Alkali-metal Chloride.

A chemically based prediction method for the equilibrium distribution ratios has been described for the solvent extraction of Cu (II) with hydroxyoxime from the quaternary solutions of HX-CuX2-MXn-H2O, where X is a univalent anion and M is a cation. This method is characterized by the employment of Pitzer's estimation equations for the stoichiometric activity coefficients of the aqueous species and for the excess volume of the aqueous phase. In order to determine the accuracy of the computational results, extraction experiments have been performed using Acorga P-5100 as the extractant under various HCl and MCl (M=Li, Na, or K) concentrations with the constant initial CuCl2 concentration of 0.1mol·dm-3, exhibiting a gradual decrease in the distribution ratios with the increase in MCl. The degree of the decrease is independent of the species of M.The present method can predict the distribution ratios very accurately at least up to an MCl concentration of 3 mol·dm-3 when M is Li or Na. When M is K, the agreement is good within a limited MCl concentration range, which could be extended if mixing parameters-between MCl and CuCl2 for the activity coefficient estimation become available.The dependencies of the extraction behavior on the concentrations of hydrogen ions and alkali-metal chlorides were discussed in terms of the changes in the activity coefficients of cupric and hydrogen ions.

Distribution Equilibria of Five β-Diketones and Their Complexes of Copper (II) and Iron (III) in 4-Methyl-2-pentanone- Aqueous Perchlorate Solution Systems

Chemical equilibria of liquid-liquid distributions of acetylacetone, benzoylacetone, trifluoroacetylacetone, benzo-yltrifluoroacetone, and hexafluoroacetylacetone, (HA), and solvent extraction of Cu(II) and Fe(III) with these β-diketones were determined in 4-methyl-2-pentanone(MIBK)-aqueous perchlorate solution systems. The results are compared with those obtained in systems where carbon tetrachloride is the solvent. The distribution constant of HA in the MIBK systems is higher when the acid is stronger. This dependence is opposite to that found in the carbon tetrachloride systems. The extraction of Cu(II) into MIBK with the β-diketones having trifluoromethyl group is better than into carbon tetrachloride. However, such a better extraction is usually not found with acetylacetone and benzoylacetone. Although iron(III) is extracted as cationic chelates with perchlorate ions into MIBK, its extraction as the FeA3 chelate with the, β-diketones is in most cases poorer than into the latter solvent. Two types of equilibrium constants for the metal extraction were calculated, they are critically discussed.

Solvent Extraction of Copper(II) with 2-(o-Hydroxyphenyl)benzothiazole

Abstract Equilibrium and kinetic aspects of the solvent extraction of Cu(II) with 2-(o-hydroxyphenyl)benzothiazole have been carried out using a water–chloroform system. The complex extracted into chloroform was greenish-brown in color and the absorbance at 490.0 nm obeyed Beer’s law up to 2×10−4 mol/dm3. The complex was 1 : 2 (Cu2+ : ligand) type and the over-all stability constant, β2, was 1.3×1017 at an ionic strength of 0.3. The extraction constant, Kex, was 2.5×10−8. The extraction kinetics were first order with Cu(II) ions and the reagent anions. The rate constant for the reaction was found to be 5.0×109 mol−1 min−1.

The solvent extraction of Cu(II), Ni(II), and Co(II) with benzil-mono-(2-pyridylhydrazone)

BmPH has been studied as an extracting agent for the ions Cu2+, Ni2+, and Co2+·Cu2+ is extracted with an efficiency of 95% and better in the pH range 4–6, as the ion pair complexes [Cu(OH)(HL)]·ClO4 and [CuL]·ClO4. The ions Ni+4 and Co+2 are extracted as the neutral species most likely as [M(II)(OH)(L)]. There is marked curvature in the plots of logD vs. pH and a lowered extraction efficiency compared to Cu+2. While the reagent appears to be quite sensitive for the extracted Cu+2 complex, there is minimal selectivity as all three ions have overlapping absortion maxima in the same wavelenth region.

Search for optimal conditions for the extraction of thiosulfate complexes of Cu(II) by 4-(5-nonyl)pyridine from aqueous mineral acid solutions

Solvent extraction of Cu(II) by 4-(5-nonyl)pyridine (NPy) in benzene from mineral acid solutions containing thiosulfate ions has been studied at room temperature (23±2°C). Mineral acid solutions alone constitute an aqueous phase from which Cu(II) is not extracted. Addition of small amounts of thiosulfate ions augments the extraction to an extent that quantitative recovery is possible. Stoichiometric studies reveal the involvement of ion-pair type complexes (NPy·H)2·Cu(S2O3)2 which are responsible for extraction. Stability constants lg Kex for this complex are 7.2±0.2; 9.1±0.2 and 9.5±0.2 for HCl, HNO3 and H2SO4, respectively. The presence of 0.01 mol/l of some complexing ions like ascorbate, acetate, citrate, oxalate, tartrate or iodide does not affect the extraction, thus allowing the recovery of the metal from diverse matrices. Under optimal conditions (0.1M NPy in benzene-0.1M HNO3 or H2SO4+0.01M S2O3−2 or 0.5M HCl+0.05 M S2O3−2) a clean separation from some elements, e.g. Cs(I). Co(II), Fe(III), Eu(III), Ce(III), Se(IV) and Cr(VI) can be achieved.

The solvent extraction of Cu(II), Ni(II) and Co(II) with benzil mono(2-quinolyl)hydrazone

Benzil mono(2-quinolyl)hydrazone, BmQH, has been studied as an extracting agent for Cu(II), Ni(II) and Co(II). Though the uncomplexed ligand remains undissociated in the pH range 3.5–10, it can lose a proton on complexation with metals, owing to the electron-withdrawing effects of neighbouring groups. The dependence of degree of extraction on pH indicates that complexes of both Cu 2+ and Cu(OH) + are extracted. Cu(BmQH) 2 and Cu(OH)BmQH species are extracted into MIBK, and the Cu(OH)BmQH complex is extracted into benzene. In the vicinity of pH 5.5–6, extraction efficiencies greater than 95% can be achieved with both solvents. Both Ni(II) and Co(II) also show dependence of extraction on pH, but precipitation of both metals in the vicinity of pH 6 limits further studies.

Determination of Cu and Ni in French geological standards AN-G, BE-N and MA-N

Using radiochemical separation, the content of Cu and Ni were determined in French geological standards AN-G (anorthosite) BE-N (basalte) and MA-N (granite). Separation was done by solvent extraction of Cu(II) and Co(III) (reaction58Ni(n, p)58Co) as DDC complexes in CHCl3.

Solvent extraction of Cu(II) by Schiff bases—II

Aromatic 2-hydroxyaldehydes have been condensed with a number of aliphatic and aromatic amines to form a series of bi-, tri- and tetradentate Schiff bases. These have been used to extract Cu(II) into chloroform, methyl isobutyl ketone and toluene; most have been found to be effective extractants. The characteristics of these extraction systems have been explained in terms of extraction rates and the stability of the reagents to hydrolysis.

Solvent extraction of copper(II) with chlorendic acid

The solvent extraction of Cu(II) with chlorendic acid has been studied The composition of the extracted species appears to be a function of pH. In the pH range 3.2–4.6, a monomeric species exists [Cu(II)(L 2−], while at pH values greater than 4.5, a dimer in the form of [Cu(II)(L 2−)· H 2L] 2 and/or [Cu(II)(HL −) 2] 2 is extracted.

Versatic Acid 911による金属イオンの溶媒抽出に対する温度の影響

The effect of temperature on the solvent extraction of Cu, Ni, Co and Mn with Versatic acid 911 diluted in benzene was studied. Extraction temperature was varied between 10 and 60°C, and the results obtained are summarized as follows:(1) The equilibrium distribution ratio of metal is raised with the temperature. (2) The change in the composition of extracted species was not observed in the extraction of Cu and Ni in this temperature range, while the extracted species of Co was of dimeric form above 40°C and Mn ion was oxidized in the aqueous phase above the same temperature. (3) The extraction reaction of these metals is endothermic, and the heat of extraction of Cu, Ni and Co were 10.8, 14.5 and 18.9 kcal/mol, respectively. (4) A linear relationship in the form of pH0.5=a+bT−1 (a, b: constant) was observed in the extraction of these metals.

The solvent extraction of Cu(II) with pivalic acid

Studies of the distribution of Cu(II) between an aqueous phase and toluene containing excess pivalic acid have enabled the average constitution of the extracted species to be determined. Under the experimental conditions studied the organic phase appears to contain about 10% of the monomeric complex in addition to the more prevalent polymeric species.