Membrane extraction for separation of copper cations from acid solution using polypropylene hollow fibre membrane

The membrane extraction of copper ions was carried out using hydrophobic poly(propylene) (PP) hollow fiber membrane modules and kerosene solutions containing organic extractant. The influences of different extractant on the extraction yield, mass transfer performance and mass transfer mechanism were studied. Compared with 2‐ethylhexyl phosphoric acid (2EHPA) and 2‐methyl‐5‐sulpho benzaldoxime (2M5SB), di‐(2‐ethylhexyl)phosphoric acid (D2EHPA) extractant system with high distribution coefficient exhibited higher extraction yield of 99.7%. The extraction equilibrium time, the final extraction yield and the total mass transfer coefficient were independent of the flow rates of two phases. The extraction equilibrium time and the final extraction yield at different flow rates of two phases were 80 min and near 99.5%, respectively. A mass transfer model of a complexation reaction describing the overall mass transfer resistance was controlled by interfacial reactions rather than the aqueous and organic boundary layer which could explain the effect of flow rate on the final extraction yield and the total mass transfer coefficient. This model showed that the mass transfer resistance and mass transfer coefficient were independent of Cu²⁺ when copper ion concentration was more than 0.06 g/L. However, when copper concentration was less than 0.06 g/l, the mass transfer resistance increased as Cu²⁺ concentration decreased, and the mass transfer coefficient decreased as Cu²⁺ concentration decreased. Extractant entrainment in the aqueous phase and membrane fouling were investigated primarily. It was found that the solvent entrainment could reduce to 10 ppm much lower than 200 ppm of the classic liquid–liquid extraction, and that the cleaning of contaminated membranes was not complete. However, it can be still concluded from this research that the membrane extraction in PP hollow fibre with D2EHPA extractant would be an effective and promising processing means for Cu²⁺ separation from aqueous solution. Copyright © 2005 John Wiley & Sons, Ltd.     

Modelling and experimental validation of enantioseparation of racemic phenylalanine via a hollow fibre-supported liquid membrane

This paper reports on the enantioseparation of racemic phenylalanine or D-phenylalanine and Lphenylalanine via a hollow fibre-supported liquid membrane (HFSLM) and the results are compared with the mathematical model. The enantioseparation results, of 80 % and 73 %, showed the highest extraction and stripping of l-phenylalanine from the feed phase and the enantiomeric excess (% ee) of 60 % from 6 mmol L^?1 of initial rac-phenylalanine in the feed solution. The optimum parameters were feed solution at pH 5, 6 mmol L^L?1 of O,O′-dibenzoyl-(2S,3S)-tartaric acid ((+)-DBTA) as the extractant in octanol as the liquid membrane, and deionised water as the stripping solution. Equal flow-rates of feed and stripping solutions of 100 mL min^L?1 were adjusted in a batch operation mode for 50 min at ambient temperature. From the calculation, the equilibrium constants of extraction (K _ex) and mass transfer coefficients in the feed phase (k _f) and in the liquid membrane phase (k _m) were found to be 1.81 L mmol^?2, 3.50 × 10^?2 cm s^?1, and 1.40 × 10^?2 cm s^?1, respectively. Finally, the change in concentrations of d,l-phenylalanine over time in the feed and stripping solutions by mathematical model were estimated and compared with the experimental results. The values thus calculated were in agreement with the experimental data with the average deviation of approximately 3 %.     

A Comparative Study of the Solvent Extraction of the Trivalent Elements of the Lanthanoid Series with Thenoyltrifluoroacetone and 4-Benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one Using Diphenylsulphoxide as Synergistic Agent

Solvent extraction of the trivalent lanthanoids (except Pm) with mixtures of a chelating extractant, either 1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedione (thenoyltrifluoro-acetone, HTTA) or 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (HP) and diphenylsulphoxide (S), from chloride solutions has been studied in C₆H₆. It was found that, in the presence of a diphenylsulfoxide, the lanthanoids were extracted as Ln(TTA)₃⋅S and LnP₃⋅S. The extraction data have been analyzed by a graphical method taking into account aqueous phase speciation and the plausible complex extracted into the organic phase. On the basis of the experimental data, values of the equilibrium constants have been calculated. Positive values of the synergistic coefficients show that all lanthanoids are extracted synergistically upon the addition of compound S to the chelating extractant. The separation of the lanthanoids with synergistic mixtures was, in most cases, a little higher than those obtained using HTTA or HP alone.     

Extraction of copper(II) ions from ammonia solutions with a β-diketone extractant

The extraction of copper(II) ions from ammonia solutions with a new β-diketone extractant, DX-510A, has been studied. Kinetic features of the copper(II) extraction and back extraction have been established: the reaction orders have been determined, and extraction and stripping rate constants have been calculated to be k_e1 = 4.14 × 10^–2 s^–1 and k_be1 = 3.20 × 10^–2 s^–1, respectively. It has been demonstrated that the extraction of copper(II) ions is not accompanied by the coextraction of ammonia. The type of extracted complex has been determined and its formula has been suggested.     

Ionic liquid as hollow fibre membrane carrier for extraction of fluoroquinolone antibiotics in milk coupled with high-performance liquid chromatography quantification

A new hollow fibre liquid phase microextraction technology with an ionic liquid as the carrier was developed to determine the fluoroquinolone antibiotics in milk. In this technology, a porous polypropylene hollow fibre was filled with aqueous ionic liquid and the extraction efficiency of different factors, such as the type of hollow fibre membrane carrier, the pH and ionic strength of the donor solution, the pH of the acceptor solution, the stirring rate and the extraction time, were investigated. The optimised extraction condition was: [OMim][BF₄] impregnated in the pores of the hollow fibre; 0.1?mol?L^?1 of Na₂HPO₄ (pH 11.0) as the acceptor solution was injected into the lumen of the hollow fibre; 0.1?mol?L^?1 H₃PO₄ (pH 5.0) was used as the donor solution; 600?rpm was selected as the stirring rate; 120?min was the optimum extraction time. The proposed method provided very high factors with 130-fold, 156-fold and 116-fold enrichment of ofloxacin, ciprofloxacin and enrofloxacin, respectively.     

Extraction of thorium(IV), lantanum(III), and yttrium(III) nitrates with a composite solid extractant based on a polymeric support impregnated with trialkylamine

Extraction of Th(IV), La(III), and Y(III) from aqueous solutions containing 0–4 M sodium nitrate with a composite solid extractant based on a polymeric support impregnated with trialkylamine (Alamine-336) was studied. The extraction isotherms were analyzed assuming that lanthanides and thorium are extracted with the solid extractant in the form of complexes (R₃HN)₃[Ln(NO₃)₅] and (R₃HN)₂[Th(NO₃)₆], respectively. The extraction constants were calculated. The joint extraction of Th(IV) and La(III) [Y(III)] with the solid extractant from aqueous salt solutions was studied.     

Extraction of Th(IV), La(III), and Y(III) nitrates with a composite solid extractant based on a polymeric support impregnated with trialkylmethylammonium nitrate

Extraction of Th(IV), La(III), and Y(III) from aqueous solutions containing 0–4 M sodium nitrate with a composite solid extractant based on a polymeric support impregnated with trialkylmethylammonium nitrate (Aliquat-336) was studied. The extraction isotherms were analyzed assuming that lanthanides and thorium are extracted with the solid extractant in the form of complexes (R₄N)₂[Ln(NO₃)₅] and (R₄N)₂[Th(NO₃)₆], respectively. The extraction constants were calculated. The joint extraction of Th(IV) and La(III) [Y(III)] with the solid extractant from aqueous salt solutions was studied.     

Amoxicillin removal from aqueous solutions using hollow fibre supported liquid membrane: kinetic study

Amoxicillin was removed from aqueous solutions using hollow fibre supported liquid membrane system (HFSLM). After evaluation of the influencing variables, the highest permeation coefficient of amoxicillin reached 2.778 × 10^?4 ms^?1 when the length of hollow fibres was 15 cm and the operating time was 60 min. Then, the reaction flux models of extraction and stripping were calculated. Thereafter, the modelling results were compared with the experimental data at standard deviations of 2.07 and 3.19%. In the comparison of carrier and diluent, the best conditions were achieved when Aliquat 336 and 1-Decanol were used. Results showed that amoxicillin extraction and stripping were of first and zero reaction orders; their reaction rate constants were 0.0344 min^?1 and 0.0445 mg/L·min, respectively.     

Extraction and re-extraction of phenylalanine by cationic reversed micelles in hollow fibre contactors

This work reports the extraction of phenylalanine with a reversed micellar system consisting of TOMAC/hexanol/n-heptane using hydrophobic hollow fibre modules. Extraction studies were performed under different hydrodynamic conditions and mass transfer correlations for the shell and tube sides were developed. The correlations were determined using a one-step calculation method and the results obtained are in agreement with the literature for the range of Reynolds numbers studied.Based on the obtained correlations and on the resistance in series model, a transport model was developed in which the phenylalanine concentration in the feed phase can be predicted during the experimental run. For the extraction process the model developed describes satisfactorily the evolution of phenylalanine concentration with time under different hydrodynamic conditions. The re-extraction process was found to be kinetically controlled due to the higher dynamic stability of reversed micelles when contacting a stripping phase with high ionic strength. The experimental results obtained were described using a kinetic model developed.Simultaneous extraction/stripping of phenylalanine was also accomplished using two hollow fibre modules in series, using different volume phase ratios. The mass transfer process was modelled and compared with the experimental results.     

Solvent extraction of copper(II) from sulfate medium with N -(2-hydroxybenzylidene)aniline

Solvent extraction of copper(II) from sulfate medium with N-(2-hydroxybenzylidene)aniline is studied with the following parameters: pH, concentration of the extractant, nature of diluent, and temperature. The extraction of copper(II) proceeds by a cation exchange mechanism and the extracted species are CuL₂ in cyclohexane and toluene and CuL₂ with some CuL₂HL in chloroform. The equilibrium constants have been calculated as well as thermodynamic parameters ΔH°, ΔS°, and ΔG°. The temperature effect on the solvent extraction of copper(II) with N-(2-hydroxybenzylidene)aniline in cyclohexane is discussed.     

Investigation of 7-((dioctylamino)methyl)quinoline-8-ol for uptake and removal of uranyl ions

A new 8-hydroxyquinoline derivative extractant was synthesized via the Mannich reaction from a secondary amine. Various analytical techniques (¹H, ¹³C NMR, FTIR, mass spectroscopy) were used to characterize our product. The use of this new extractant for the uptake and removal of uranyl ions in aqueous solution was investigated. Conditions for an effective sorption were optimized with respect to different experimental parameters in batch process. The results showed that the extraction rate increases for solutions with a pH in the range [0.65–1.13]. The total sorption capacity was 105 (mg g^?1) under optimum experimental conditions. The extraction of UO₂ ²⁺ was found to be quantitative (100 %) at initial uranyl concentration less than or equal to 41.59 mg/L. Thermodynamic parameters showed the adsorption of an endothermic process and a spontaneous nature, respectively.     

Extraction of metals by neutral sulfur-containing extractants: Part I. o-isopropyl-n-ethylthiocarbamate

The formation of neutral mixed complexes of the MX_mS_p type (where M is a metal ion with m⁺ charge, X the inorganic anion, and S the sulfur-containing extractant) allows a selective extraction of various elements. The extraction of many metals from mineral acid solutions or from halide-sulfuric acid mixtures by 0.05 M O-isopropyl-N-ethylthiocarbamate(IPETC) solution in chloroform has been studied. (IPETC) possesses very high selectivity for silver and mercury ions in extractions from HNO₃, H_{2)SO4, HClO4 and HCl solutions. In addition to silver and mercury, Cu, Au, Tl and Se are readily extracted from solutions containing bromide. From iodide solutions, copper, gold and thallium ions may be selectively extracted because silver and mercury cannot be extracted at concentrations of iodide above 0.1 M.(IPETC} extracts metals as mixed complexes, containing the halide and apparently the extractant in the molecular form.     

Extraction chromatographic study on the separation of Am<Superscript>3+</Superscript> and Eu<Superscript>3+</Superscript> using ethyl-BTP as the extractant

Ethyl-substituted bis-triazinylpyridine (Et-BTP), a nitrogen containing soft-donor extractant, was used in investigations pertaining to the separation of Am³⁺ and Eu³⁺ from dilute nitric acid feed solutions by extraction chromatography using XAD-4 as the inert support, chlorinated dicarbollide as the modifier and 2-nitrophenyloctylether (NPOE) as the diluent. After carrying out a series of experiments, the optimum composition of the extractant mixture for the resin was found out to be 0.1 M Et-BTP and 0.025 M CCD in NPOE. Separation factor values were encouraging to carry out subsequent batch uptake studies at varying nitrate ion concentration which indicated favourable separation behaviour up to NaNO₃ concentration of 2 M. Column studies have been carried out and conditions for elution and separation of Am³⁺ from Eu³⁺ have been found out. Long term stability of the resin was also investigated.     

Extraction and complexation of Cu(II) with undecanoic acid <Emphasis Type="Italic">N,N</Emphasis>-diethylhydrazide

A new reagent, undecanoic acid N,N-diethylhydrazide, was synthesized, and its pK _a1 was determined. The reagent recovers Cu(II) to 99–100% from solutions whose acidity ranges from pH 6 to 1 M NH₃. Copper(II) is extracted in the form of a neutral complex of the composition Cu(II):reagent = 1:2. The reagent is incorporated in the complex in the deprotonated form. An equation for the extraction of Cu(II) from ammonia solutions was suggested. The extraction isotherm was constructred. Ammonium salts, when present in solution, considerably decrease the degree of copper extraction. The reagent is less efficient extractant of copper than N,N-diethylbenzhydrazide.     

Anwendbarkeit der flammenlosen Atomabsorption in der messenden komplexchemie: Verteilung von Cu(II) zwischen chloroform und wasser in Gegenwart von 8-hydroxychinolin

Atomic-absorption spectrophotometry with the graphite furnace atomizer has been used in a study of the extraction equilibria of copper oxinate. The amounts of copper back-extracted from chloroform solutions of oxine into aqueous solutions containing tetramethyl ammonium nitrate were determined, and the stability constants β₁ and β₂, and the distribution coefficient K_N for copper oxinate, were then calculated. The protonation constants K₁ and K₂ for the oxinate anion and the distribution coefficient K_HL for oxine were determined by potentiometric aqueous and two-phase titrations respectively. The values obtained are in good agreement with published data.     

Synthesis of magnetic nanoparticles for analytical applications

A simple method based on magnetically assisted chemical separation has been developed for analytical purposes. In this method, morin-modified magnetic nanoparticles were used for the selective extraction and preconcentration of copper ions from aqueous solutions. The influence of different parameters, such as the presence of the morin extractant, the amount of morin extractant loaded on the nanoparticles, the pH, adsorption time and the type and minimum amount of eluent required for elution of the copper from the magnetic nanoparticles, were evaluated. The detection limit of the proposed method followed by ICP–OES was found to be 1.3 µg L^?1 and a dynamic linear range of 10–200 µg L^?1 was obtained. The relative standard deviation was less than 5%. The method was applied to the recovery and determination of copper in real samples.     

Extraction of zirconium(IV) from hydrochloric acid solutions by tri-octylamine and neutral donors

Solvent extraction of Zr(IV) from aqueous HCl solutions by mixtures of TOA and different organophosphorous bases in carbontetrachloride solvent have been found to be always higher than that by any single extractant. Synergism has been observed in the range of 2.4–9.6M HCl. Although the species extracted with neutral donor alone seems to be ZrCl₄·TOPO etc, with a mixture of extractants, however, the extracted species appears to be Q₂ZrCl₆·TOPO where Q is R₃NH. The extraction has also been found to increase with increase in the concentration of amines and neutral donors. Enhancement of extraction has been explained by the formation of a complex adduct in organic phase. Synergistic coefficients and apparent formation constants of the complex adducts have also been calculated.     

Extraction of europium from mixed acids and mixed aqueous—Organic media

The extraction of Eu with Amberlite LA-2, TBP and HDEHP from HF, HCl, HBr, H₂SO₄, CH₃ COOH and KI solutions was investigated. The extraction of Eu with TBP and LA-2 is small over a wide range of concentrations. The extraction of Eu with HDEHP from HCl, HBr, and H₂SO₄ is inversely proportional to the third power of the acid concentration, while the extraction from KI is proportional to the square of the extractant concentration. The extraction by the three extractants from H₂SO₄ in presence of small amounts of hydrogen halides is small. These extraction data can be used to separate Eu from Th and many of the fission products. The presence of water-miscible alcohols and acetone generally increases the extraction of Eu from H₂SO₄ and KI solutions.     

Dispersion-free solvent extraction of U(VI) in macro amount from nitric acid solutions using hollow fiber contactor

The applicability of dispersion-free solvent extraction (DFSX), through microporous hydrophobic membrane has been studied. The hollow fiber membrane contactor, with surface area of 381 cm² was employed to extract U(VI) in macro concentration (35 g dm⁻³) from aqueous acidic solutions. Prior to deployment of this technique for recovery of U(VI) from oxalate supernatant waste, chemical parameters such as extractant concentration, feed acidity, concentration of U(VI) in feed were studied. The study revealed that 30% tri-n-butyl phosphate (TBP) in n-dodecane as an extractant and feed in 3 M HNO₃ gave an optimum extraction of U(VI) and it was possible to strip back utilizing 0.05 M HNO₃. It was established to recover more than 90% of U(VI) from oxalate supernatant waste, which was often generated from nuclear chemical facilities.     

Solvent extraction—atomic absorption determination of chromium(VI) in soils

The extraction of chromium(VI) from aqueous saline solutions (NaNO₃) using a trioctylamine solution in toluene was studied in order to determine chromium(VI) in soil samples by atomic absorption spectrometry. It was found that the quantitative recovery of chromium(VI) was attained after extraction with the 0.1 M extractant solution (pH 1.5) for 15 min followed by-back extraction with 4 M HNO₃. Chromium(III) was not extracted under these conditions