Comparative study of the determination of platinum by extraction with Cyanex 923 and Cyanex 471X from bromide media

The extraction equilibrium study of Pt(IV) was carried out with Cyanex 923 and Cyanex 471X in toluene from hydrobromic acid media to investigate their extraction capacity, since they have different donor atoms, ‘O’ and ‘S’. Their distribution equilibria were studied as a function of extractant concentration, diluents, hydrobromic acid concentration and the effect of temperature on extraction. Pt(IV) was quantitatively extracted with 0.1 mol dm^?3 Cyanex 923 in toluene from 5.0–8.0 mol dm^?3 HBr media and was stripped with 4.0 mol dm^?3 perchloric acid. However it was also quantitatively extracted with 0.1 mol dm^?3 Cyanex 471X (with 0.1 mol dm^?3SnCl₂) in toluene from 6.0–8.0 mol dm^?3 HBr media and was stripped with 1.0 mol dm^?3 stabilized sodium thiosulfate solution at pH 9.0. The slope analysis method indicated metal complex species of 1:1 for Pt(IV) with Cyanex 923 and Cyanex 471X in toluene from HBr media. These methods were successfully applied to the analysis of platinum in real samples. © 2001 Society of Chemical Industry     

Kinetic study of ytterbium(III) extraction from sulfate medium with Cyanex 923

The kinetics of ytterbium(III) extraction from sulfate medium with Cyanex 923 in heptane has been investigated with a constant interfacial cell with laminar flow, which aimed to identify the extraction regime, reaction zone and rate equations. It was found that the extraction rate of ytterbium(III) increased linearly with stirring speed and specific interfacial area. The activation energy E_a (9.56 kJ mol^?1), activation enthalpy ΔH^± (7.05 kJ mol^?1), activation entropy ΔS^±₂₉₈ (?0.31 kJ mol^?1) and Gibbs free energy of activation ΔG^±₂₉₈ (98.3 kJ mol^?1) were calculated from the dependence of extraction rate on temperature. The experiential rate equations were obtained by investigating the influence of the concentration of various species on the extraction rate. A diffusion regime has been deduced from evidence of the linear dependence of extraction rate on stirring speed and the low value of the activation energy. The liquid–liquid interface is most probably the reaction zone in view of the linear dependence of extraction rate on specific interfacial area, the high interfacial activity and low water‐solubility of extractant. Thus the mass transfer rate is controlled by interfacial film diffusion of species. Copyright © 2007 Society of Chemical Industry     

Studies on the Solvent Extraction of Rare Earth Metals from Fluorescent Lamp Waste Using Cyanex 923

The growing need for materials such as rare earth metals (REMs) has focused attention towards their recovery from various end-of-life products. Fluorescent lamps are considered a viable target, and can be a source of up to six REMs: lanthanum, cerium, europium, gadolinium, terbium, and yttrium. In this study a commercial mix of trialkylphosphine oxides (Cyanex 923) was investigated for the extraction of REMs from fluorescent lamp waste leachates. The kinetics of the extraction is addressed, together with the co-extraction of undesired elements (iron and mercury), the influence of temperature, nitric acid concentration in the aqueous phase and ligand concentration in the organic phase. The extraction of REMs was found to be enthalpically driven, with good separation factors between the light and heavier elements. Selective stripping of REMs was possible in a single step using 4 M hydrochloric acid solution. Further recovery of iron and mercury was carried out using nitric and oxalic acid solutions.     

Opposite selectivities of tri-n-butyl phosphate and Cyanex 923 in solvent extraction of lithium and magnesium

The synergic solvent extraction system of tri-n-butyl phosphate (TBP) and FeCl₃ (or ionic liquids, ILs) has been extensively studied for selective extraction of Li from Mg-containing brines. However, Cyanex 923 (C923), which extracts many metals stronger than TBP, has not yet been examined for Li/Mg separation. Here, we report on the unexpected observation that the C923/FeCl₃ system has opposite Li/Mg selectivity compared to the TBP/FeCl₃ system. Detailed investigations show that the opposite selectivity of the C923/FeCl₃ (or IL) system is due to three factors: (1) the strong extraction of Fe by C923 leads to a low concentration of [FeCl₄]⁻ in the system, which is essential for Li extraction; (2) C923 in combination with an IL extracts Mg strongly by an ion-pair mechanism; (3) most importantly, C923 extracts Mg by solvation, resulting in an insufficient concentration of C923 for Li extraction. The unexpected poor Li/Mg selectivity of C923 highlights the irreplaceable role of TBP in the selective recovery of Li.     

Salt Effects on the Recovery of Phenol by Liquid‐Liquid Extraction with Cyanex 923

Abstract

In this work, the effect of salt addition on the recovery of phenol from a 46 g/L aqueous solution simulating a phenolic resin plant effluent by liquid‐liquid extraction at 298 K has been studied by using an organic phase containing 0.6 M Cyanex 923 extractant in ShellSol T. Addition of sodium sulfate, potassium nitrate, and sodium chloride to the aqueous phase was tested and sodium chloride was selected. Based on the obtained results, a study of phenol recovery process was undergone by taking advantage of the salting‐out effect. Equilibrium curves are presented for liquid‐liquid extraction with and without salt addition to the aqueous phase. An integrated process involving salting‐out and liquid‐liquid extraction was proposed. The stripping concentrates can be reused for phenolic resin production.     

三氯乙烯与糠醛水溶液的液液平衡及萃取模拟计算

本文采用液液平衡釜了糠醛水溶液与三氯乙烯的液液平衡数据，用ＵＮＩＱＵＡＣ方程关联糠醛－水－三氯乙烯体系的液液平衡数据，以ＵＮＩＱＵＡＣ方程的模型，采用液液萃取法模拟计算糖醛和水的分离结果。     

Solvent extraction of Zn(II) by Cyanex 923 and its application to a solid‐supported liquid membrane system

The extraction of zinc(II) by Cyanex 923 (phosphine oxides mixture) in Solvesso 100 from hydrochloric acid solution has been investigated. The extraction reaction is exothermic. The numerical analysis of metal distribution data suggests the formation of ZnCl₂·L₂,HZnCl₃·2L and H₂ZnCl₄·2L(L = ligand) in the organic phase with formation constants K_ext = 4.1,5.6 × 10⁹ and 6.7 × 10⁹, respectively. The results obtained for zinc(II) distribution have been implemented in a solid‐supported liquid membrane system. The influence of source phase stirring speed, membrane composition and metal concentration on zinc transport have been investigated. © 2001 Society of Chemical Industry     

Liquid–liquid extraction of cadmium(II) by Cyanex 923 and its application to a solid‐supported liquid membrane system

The extraction of cadmium(II) by Cyanex 923 (a mixture of alkylphosphine oxides) in Solvesso 100 from hydrochloric acid solution has been investigated. The extraction reaction is exothermic. The numerical analysis of metal distribution data suggests the formation of CdCl₂.2L, HCdCl₃.2L and H₂CdCl₄.2L (L = ligand) in the organic phase. The results obtained for cadmium(II) distribution have been implemented in a solid‐supported liquid membrane system. The influences of feed phase stirring speed (400–1400 min^?1), membrane composition (carrier concentration: 0.06–1 mol dm^?3) and metal concentration (0.01–0.08 g dm^?3) on cadmium transport have been investigated. Copyright © 2005 Society of Chemical Industry     

Extraction and Separation of Germanium Using Cyanex 301/Cyanex 923. Its Recovery from Transistor Waste

Abstract

The extraction of Ge(IV) from HCl, HNO₃ and H₂SO₄ media in toluene solution of Cyanex 301 and Cyanex 923 is investigated. It is almost quantitatively extracted (～95%) in Cyanex 301 and Cyanex 923 at 8 molL^?1 HCl but the extractions from H₂SO₄ and HNO₃ are poor in the entire investigated range of acid molarity. Detailed investigations were carried out from HCl medium. Based on the slope analysis data the extracting species is identified as GeCl₄·2R (R=Cyanex 301/Cyanex 923). The extraction of Ge(IV) is higher and comparable in diluents like toluene, n‐hexane and kerosene (160–200°C) and there is no correlation between the dielectric constant and the percent extraction. The extractants are stable towards prolonged acid contact and there is negligible loss in their extraction efficiency even after recycling them for several cycles. The extraction behavior of commonly associated metal ions namely As(V)/(III), Sn(IV), Tl(III), In(III), Ga(III), Fe(III), Al(III), Hg(II), and Cu(II) has also been investigated. Based on the partition data conditions for attaining some binary and ternary separations involving Ge(IV) have been optimized. The separation data have been fused to develop a scheme for the recovery (93%) of pure germanium (～99%) from semi conductor waste.     

Extraction separation of Ir(III) and Rh(III) with Cyanex 923 from chloride media: a possible recovery from spent autocatalysts

Liquid–liquid extraction of Ir(III) and Rh(III) with Cyanex 923 from aqueous hydrochloric acid media has been studied. Quantitative extraction of Ir(III) was observed in the range of 5.0–8.0 mol dm^?3 HCl with 0.1 mol dm^?3 Cyanex 923, while Rh(III) was extracted quantitatively in the range of 1.0–2.0 mol dm^?3 HCl with 0.05 mol dm^?3 Cyanex 923 in toluene along with 0.2 mol dm^?3 SnCl₂. The Ir(III) was back extracted with 4.0 mol dm^?3 HNO₃ quantitatively from the organic phase while Rh(III) was stripped with 3.0 mol dm^?3 HNO₃. The extraction of Rh(III) with Cyanex 923 was not quantitative without use of SnCl₂. However in the extraction of Ir(III) a negative trend was observed in the presence of SnCl₂. Varying the temperature of extraction showed that the extraction reactions of both the metal ions are exothermic in nature, and the stoichiometric ratio of Ir(III)/Rh(III) to Cyanex 923 in organic phase was found to be 1:3. The methods developed were applied to the recovery of these metal ions from a synthetic solution of similar composition to that from leaching of spent autocatalysts in 6.0 mol dm^?3 HCl. © 2002 Society of Chemical Industry     

Carrier-facilitated transport of Cd(II) from a high-salinity chloride medium across a supported liquid membrane containing Cyanex 923 in Solvesso 100

The transport of cadmium (II) from a high-salinity chloride medium across a flat-sheet supported liquid membrane containing Cyanex 923 in Solvesso 100 supported on a PVDF membrane into a strip solution with water was investigated. Permeability coefficients of metal increased with decreasing the pH of feed from 2.0 to 0.5. It also increases with increasing carrier concentration in the membrane phase, whereas the permeation is dependent on the organic phase diluent but independent of metal concentration in the feed phase. The performance of the present system against other carriers was also studied.     

苯酚羟化液萃取脱水的液液相平衡数据的测定

本文研究了异丙醚和甲基异丁基甲酮作为苯酚羟化液萃取脱水剂在20℃时的液-液相平衡关系。采用浊度法和色谱法相结合的策略测定了体系的相平衡曲线,并绘制了三元相图：从三元相图的平衡曲线看,所用萃取剂具有较好的萃取性能。     

Separation of phenol and formaldehyde from industrial wastes. Modelling of the phenol extraction equilibrium

BACKGROUND: The manufacture of phenolic resins causes the generation of hazardous wastes composed of high concentrations of phenol and formaldehyde together with low molecular weight polymers in lower concentrations. The separation of phenol, mainly from synthetic aqueous solutions, has been successfully achieved by means of solvent extraction, 8 - 17 but few references tackle the treatment of industrial wastes because of their complex behaviour. This work aims at the experimental and theoretical analysis of the recovery of phenol from industrial aqueous wastes using CYANEX 923 as organic extractant. RESULTS: Aqueous condensates containing phenol in the concentration range 40–280 g L^?1, and formaldehyde in the range 30–110 g L^?1, were contacted with CYANEX 923 to analyse the influence of feed pH and of concentration of the selective extractant on the extraction equilibrium. Concerning the pH of the feed phase, it was observed that for values higher than 8.0 a decrease in the distribution ratio of phenol between the organic and the aqueous phases took place. Additionally, caustic conditions promoted formaldehyde degradation reactions in the feed phase. Phenol recovery from the loaded organic extractant was obtained by stripping with NaOH solutions. Best results were obtained working with a CYANEX 923 concentration 0.6 mol L^?1. CONCLUSION: Analysis of the experimental data established the optimum conditions of the selective extraction of phenol from industrial condensates. A mathematical model based on the extraction reaction of 2 moles of phenol per mole of Cyanex 923 described successfully the experimental results. The equilibrium parameter was estimated from the fitting of experimental data to the mathematical model obtaining a value of K = 750.9 (mol L^?1)^?2. Copyright © 2010 Society of Chemical Industry     

水-环己烷-乙醇体系的液液平衡研究

用GC-14B气相色谱仪测定了水-环己烷-乙醇体系在298.15K、308.15K、318.15K和328.15K的等温截面相图.所用方法是内标法,内标物为乙酸乙酯,溶剂正丁醇.实验测定了除水以外各组分的保留时间和相对校正因子,相对校正因子的实验值与文献值很接近.在单相区域,对实验准确度进行了验证,均方根实验误差1.51%.给出了四个等温截面的两相平衡实验数据和相应的示意图.其相图特征与水-正己烷-甲醇体系相仿;当醇浓度不大时,存在较大的水相、油相共存区域;醇浓度较大时为单相区域.但在水-环己烷-乙醇体系中,单相区域随温度增加明显增大.     

Extraction of Phenol Using Trialkylphosphine Oxides (Cyanex 923) in Kerosene

Abstract

A group of extractants based on phosphine oxides have been reported as an alternative to conventional polar solvents for phenol liquid-liquid extraction. Among phosphoryl extractants, Cyanex 923 (a mixture of four trialkylphosphine oxides, alkyl = normal, C₆, C₈) has proved to combine high extraction efficiency and low water solubility (1, 2), obviating the necessity of removing the solvent from the aqueous raffinate, a need asso- ciated with the use of methyl isobutyl ketone and isopropyl ether, the solvents most widely employed for this application (3, 4).     

复合萃取剂-磷酸-水三元体系液液相平衡研究

研究了复合萃取剂-磷酸-水三元体系在25℃下的液液相平衡关系,绘制了三角相图,用Hand公式对相平衡数据进行了关联。考察了不同温度条件下磷酸分配系数随原料酸中磷酸含量的变化关系,结果表明磷酸的分配系数随温度变化不大;同时,研究了磷酸中钙镁离子在两相中的分配情况,结果表明复合萃取剂对离子具有很好的选择性。     

Extraction of Lanthanum and Samarium from Nitrate Medium by some Commercial Organophosphorus Extractants

Abstract

The extraction of lanthanum(III) and samarium(III) from nitrate solutions by some phosphine oxide compounds (Cyanex 921, Cyanex 923, and Cyanex 925) in kerosene was investigated. The influence of the different factors affecting the extraction was studied in detail. The extraction of these metals using the above extractants was compared and the sequence of extraction was found to be Cyanex 921>Cyanex 923?Cyanex 925. The stripping percent of La(III) and Sm(III) by 0.75 M HNO₃ from the loaded organic phase after two stages were 72% and 5.2%, respectively, which could enable a good separation between these two lanthanides.     

Phenol Removal from Aqueous System by Bis(2-ethylhexyl) Sulfoxide Extraction

Solvent extraction is generally considered as one of the important and effective techniques to remove toxic phenol from wastewater. This paper explores the solvent extraction of phenol from wastewater using bis(2-ethylhexyl) sulfoxide (BESO) as extractant. Various parameters such as equilibrium time, the volume percentage of BESO, pH value, and ionic strength of the aqueous solution on the phenol extraction were investigated. The results indicated that BESO exhibited excellent performance of phenol extraction. The extraction percentage increased from 97.26% to 99.47%, varying the BESO concentration from 10% (v/v) to 30% (v/v). The extraction percentage decreased with increasing temperature in the range of 298-343 K. FTIR spectra of fresh and phenol loaded BESO organic phase indicated the existence of the hydrogen bonding interactions between S=O groups and phenol molecules. The relationship between log D and log [BESO] suggested the stoichiometry of the extracted species was a 1:1 complex, namely, [PhOH]·[BESO]. Phenol stripping from the loaded organic phase by sodium hydroxide was feasible, and more than 99% of phenol could be stripped when the NaOH concentration was 0.5 mol L^?1. The results obtained established that BESO/kerosene extraction system has potential for practical application in the phenol removal and recovery.     

Physicochemical properties,surface active species and formation of reverse micelles in the Cyanex 923‐n‐heptane/cerium(IV)‐H2SO4 extraction system

BACKGROUND: The Cyanex^® 923 (trialkylphosphine oxides, TRPO)‐n‐heptane/cerium(IV)‐H₂SO₄ extraction system has been investigated focusing on the physicochemical properties, surface active species and interfacial phenomena. The effects of H₂SO₄ and Ce(IV) extraction on them were considered. RESULTS: Results showed that the density and refractive index reflect the mass transfer by H₂SO₄ and Ce(IV) extraction and the change of refractive index was more sensitive than density. The interfacial tension decreased on extraction of H₂SO₄ but increased on extraction of Ce(IV). The viscosity of the equilibrium organic phase increased abruptly when the extracted H₂SO₄ concentration in the organic phase reached certain high values. The formation of reversed micelles, with mean diameter of about 10 nm, at high H₂SO₄ concentrations in the organic phase, is suggested by various measurements such as viscosity, interfacial tension and dynamic light‐scattering (DLS). CONCLUSION: It is suggested that TRPO‐H₂SO₄ complexes are more surface‐active than TRPO itself and tend to aggregate into reverse micelles by self‐assembling in the organic phase but the Ce(IV)‐TRPO complexes are neutral, less surface‐active than TRPO and not helpful for reverse micelle formation. Copyright © 2008 Society of Chemical Industry