Synergistic Extraction and Separation of Heavy Lanthanide by Mixtures of Bis(2,4,4‐trimethylpentyl)phosphinic Acid and 2‐Ethylhexyl Phosphinic Acid Mono‐2‐Ethylhexyl Ester

Abstract

The extraction of Yb³⁺ from chloride solution has been studied using mixtures of bis(2,4,4‐trimethylpentyl)phosphinic acid (Cyanex272) and 2‐ethylhexyl phosphinic acid mono‐2‐ethylhexl ester (P507). The results show that Yb³⁺ is extracted into heptane as YbA₃(HA)₃ with Cyanex272, YbL₃(HL)₃ with P507, and YbA₂L₄H₃ with synergistic mixture. The equilibrium constants, formation constants, and thermodynamic functions have been determined. Extraction mechanism and extraction process are also proposed. The extraction of heavy lanthanide ions by mixtures of Cyanex272 and P507 is studied and the possibility of separating heavy rare earth ions is discussed.     

Investigation of liquid–liquid phase equilibria for reactive extraction of lactic acid with organophosphorus solvents

BACKGROUND: Lactic acid is a versatile commodity chemical with a variety of applications. Synthesis of lactic acid either through fermentation of carbohydrates or through chemical synthesis is state of the art. Separation from dilute aqueous solution is complex and accounts for the major part of production costs. Reactive extraction based on reversible adduct formation is a promising alternative for the separation of lactic acid. RESULTS: Extraction was carried out with the organophosphorus solvents tri‐n‐butyl phosphate, tri‐n‐octylphosphine oxide and Cyanex 923. Shellsol T was used as diluent. Partition coefficients increase with increasing extractant content and decreasing temperature. Cyanex 923 has several advantages compared with tri‐n‐butyl phosphate and tri‐n‐octylphosphine oxide with respect to lactic acid distribution and hydrodynamic properties. Liquid‐liquid phase equilibria for lactic acid extraction with Cyanex 923 were modeled. Selectivity of lactic acid extraction with respect to glycolic acid and formic acid was discussed. CONCLUSION: The organophosphorus extractant Cyanex 923 was found to be an appropriate solvent for lactic acid extraction from aqueous solutions. Experimental data and model data based on the Law of Mass Action showed good agreement. Lactic acid extraction from multi‐acid solution showed good selectivity compared with glycolic acid. Lactic acid selectivity is low with respect to formic acid. © 2012 Society of Chemical Industry     

Solvent extraction of praseodymium using different extractants – a synergistic study

The extraction of praseodymium was investigated from chloride media using different extractants such as D2EHPA, PC88A, Cyanex 272, Cyanex 921, Cyanex 923, Cyanex 301, Cyanex 302, LIX 84I, LIX 622N, Alamine 336, Aliquat 336 and their mixtures. The synergistic effect of Cyanex 272, Cyanex 921, Cyanex 923, Cyanex 301 and Cyanex 302 were studied with each other. Among all the combinations, the mixtures of Cyanex 921-Cyanex 301 and Cyanex 923-Cyanex 301 showed the synergistic effect on the extraction of praseodymium. Solvent extraction of Pr was carried out with the mixture of 0.5 M Cyanex 301 and 0.5 M Cyanex 923. The McCabe-Thiele diagram indicated the quantitative extraction of Pr in two counter-current stages at an A:O phase ratio of 1:2. The two-stage counter-current simulation study showed 94% of extraction efficiency.     

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     

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     

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.     

Solvent Extraction Studies for Separation of Zn(II) and Mn(II) from Spent Batteries Leach Solutions

This study aims at assessing the possibility of using solvent extraction processes for separating Zn(II) and Mn(II) dissolved in aqueous solutions obtained by acid bioleaching of spent alkaline and Zn-C batteries. In this context, Cyanex 272 and DEHPA were tested as extractant agents, and the former was shown to have better performance. Hence, the effect of four factors (equilibrium pH, extractant concentration, A/O ratio, and temperature) into three response variables (extraction efficiency of Zn, Y_Zn; extraction efficiency of Mn, Y_Mn; separation factor, β) were tested according to a full factorial design (2⁴) with two replicated center points. Our study revealed that Y_Zn depends mainly on the extractant concentration, Y_Mn on the equilibrium pH and β on the equilibrium pH, extractant concentration, and A/O ratio as well as on second and third order interactions. One extraction step is sufficient to reach high extraction of zinc in synthetic solutions, but two stages were required for real leaching liquor. The extraction kinetics is fast (less than 15 min) for both metals, even when real liquor was tested. The organic solvent can be efficiently recovered using a stripping solution of H₂SO₄ 1 M and thus the process can be considered environmentally sustainable.     

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     

Kinetics and Mechanism of Yb(III) Extraction and Separation from Y(III) with Mixtures of bis(2,4,4‐trimethylpentyl)phosphinic acid and2‐ethylhexyl phosphonic acid mono‐2‐ethylhexyl ester

Abstract

The ytterbium(III) extraction kinetics and mechanism with mixtures of bis(2,4,4‐trimethylpentyl)phosphinic acid (Cyanex272) and 2‐ethylhexyl phosphonic acid mono‐2‐ethylhexyl ester (P507) dissolved in heptane have been investigated by constant interfacial cell with laminar flow. The effects of the stirring rate, temperature, extractant concentration, and pH on the extraction with mixtures of Cyanex272 and P507 have been studied. The results are compared with those of the system with Cyanex272 or P507 alone. It is concluded that the Yb(III) extraction rate is enhanced with mixtures extractant of Cyanex272 and P507 according to their values of the extraction rate constant, which is due to decreasing the activation energy of the mixtures. Atthe same time, the mixtures exhibits no synergistic effects for Y(III), which provides better possibilities for Yb(III) and Y(III) separations at a proper conditions than anyone alone. Moreover, thermodynamic extraction separation Yb(III) and Y(III) by the mixtures has been discussed, which agrees with kinetics results. Extraction rate equations have also been obtained, and through the approximate solutions of the flux equation, diffusion parameters and thickness of the diffusion film have been calculated.     

Separation of Indium from Acid Sulfate-Containing Solutions by Ion Exchange with Impregnated Resins

Indium separation using ion exchange resins from acidic polymetallic and very diluted solutions are investigated. Since the selectivity of commercial ion exchange resins have proven to be too low for an effective separation from solutions with high content of other metals, Lewatit® TP 208 was impregnated with common extractants to enhance its properties. By resin impregnation with D2EHPA and Cyanex 272, not only the selective indium recovery was reached but also the resin capacity was increased approx. two times. The best loading and elution performance were shown by Cyanex 272-impregnated Lewatit® TP 208, increasing the indium purity in the eluate from 0.75 % to 85 %.     

Liquid-Liquid Equilibrium Study of Phenol Extraction with Cyanex 923

Abstract

Although phenol extraction with Cyanex 923 has widely been studied, liquid-liquid equilibrium between phenol and undiluted Cyanex 923 has not been thoroughly investigated. Many factors influence the phenol extraction with undiluted Cyanex 923. Increasing the phenol concentration causes a water molecule replacement in the extractant by phenol molecules. Increasing the pH value above 12 decreases the phenol distribution coefficient K_D by 99.9%. A temperature increase from 15°C to 65°C results in a K_D decrease of 70%. With increasing salt content K_D increases due to salting-out. Adding organic acids stabilizes phenol in the aqueous phase and obstructs the extraction.     

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.     

Uranium Permeation from Nitrate Medium Across Supported Liquid Membrane Containing Acidic Organophosphorous Extractants and their Mixtures with Neutral Oxodonors

Permeation of U(VI) from nitric acid solution has been studied across supported liquid membrane (SLM) using bis[2,4,4 trimethyl pentyl] phosphinic acid (Cyanex 272) either alone or in combination with neutral donors like Cyanex 923 (a mixture of four trialkyl phosphine oxides viz. R₃PO, R₂R′PO, RR′₂PO, and R′₃PO where R: n-octyl and R′: n-hexyl chain), TBP (tri-n-butyl phosphate), and TEHP (tris-2-ethylhexyl phosphate) dissolved in n-paraffin as carriers. Effect of various other parameters such as nature and concentration of receiver phase, feed acidity, uranium concentration, pore size, and membrane thickness on U(VI) transport across SLM were investigated. Transport behavior of U(VI) was also compared with other derivatives of phosphoric acids like 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A), dinonyl phenyl phosphoric acid (DNPPA) under identical conditions and it followed the order: Cyanex 272 > PC88A > DNPPA. 2 M H₂SO₄ was suitable for effective U(VI) transport across SLM. Presence of neutral donors in carrier showed significant enhancement in U(VI) permeation in the order: Cyanex 923 > TBP > TEHP. U(VI) transport decreased with increased membrane thickness as well as decrease in pore size. The optimized conditions were tested for recovery of U(VI) from uranyl nitrate raffinate (UNR) waste generated during purification of uranium.     

Solvent Extraction and Separation of Trivalent Lanthanides Using Cyphos IL 104, a Novel Phosphonium Ionic Liquid as Extractant

Solvent extraction of trivalent lanthanides from chloride solution using a novel ionic liquid Cyphos IL 104 (trihexyl(tetradecyl)phosphonium bis-2,4,4-(trimethylpentyl) phosphinate or [R₄PA]) has been investigated, while comparing the results with that of its precursors trihexyl(tetradecyl)phosphonium chloride [R₄PCl or Cyphos IL 101], Cyanex 272 [HA] and their equimolar mixture. The results also indicate very high extractability of Cyphos IL 104 toward trivalent lanthanides. Unlike the conventional acidic extractants, extraction of trivalent lanthanides with Cyphos IL 104 increases the equilibrium pH of the aqueous phase due to the preferential extraction of acid over the lanthanide ions. Extraction mechanism has been established by studying the extraction of neodymium(III) with the ionic liquid as a function of the concentrations of Cyphos IL 104 and chloride ions. Separation studies of trivalent lanthanides from a mixed solution containing 1 × 10^?4M each of La, Nd, Gd, and Lu with Cyphos IL 104 or Cyanex 272 indicate that Cyphos IL 104 is a better extractant in terms of extraction coefficient, but Cyanex 272 exhibits better selectivity toward heavier lanthanides. The prospects of stripping and regeneration of ionic liquid (Cyphos IL 104) have also been discussed in the present study.     

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     

膦(磷)类萃取剂浸渍树脂吸附重稀土的性能

利用静态法研究了5种不同膦(磷)类萃取剂的浸渍树脂在盐酸介质中对重稀土的吸附行为. 结果表明,Cyanex272与膦(磷)类萃取剂组成的双萃取剂的浸渍树脂在同等实验条件下比单一Cyanex272萃取剂的浸渍树脂对重稀土具有更好的吸附性,其中以Cyanex272与P507, Cyanex302, Cyanex923和TBP分别按体积比1:1, 5:1, 1:1, 2:1混合为最优. 吸附最佳pH值在3.0~4.0之间,吸附平衡时间为50 min,升高温度对吸附有利. 在相同实验条件下,5种浸渍干树脂Cyanex272, Cyanex272-P507, Cyanex272-Cyanex302, Cyanex272-Cyanex923, Cyanex272-TBP对重稀土的饱和吸附容量分别为20.04, 25.37, 21.87, 22.16, 38.48 mg/g.     

CYANEX 923 AS AN EXTRACTANT FOR TRIVALENT LANTHANIDES AND YTTRIUM

ABSTRACT

The extraction of yttrium and some trivalent lanthanides from thiocyanate and nitrate solutions using Cyanex 923 { TRPO ) in xylene as an extractant has been investigated. It has been found that these trivalent metal ions are extracted from thiocyanate solution as M(SCN)₃.n TRPO ; n in general having the values of 4 and 3 for the lighter and the heavier lanthanides respectively. On the other hand, from nitrate solutions these trivalent metal ions are extracted as M(NO₃)₃ 3 TRPO. The equilibrium constants of the extracted complexes have been obtained by non-linear regression analysis. In both the thiocyanate and nitrate systems, the distribution ratios of trivalent lanthanides are found to increase with decreasing ionic radii and the distribution ratio of yttrium lies along with those of the middle lanthanides. The separation factors between these trivalent metal ions were evaluated and compared with those obtained using commercially important extraction reagents like tributylphosphate (TBP), trioctylphosphine oxide (TOPO) and di-2-ethylhexylphosphoric acid (DEHPA). The separation possibilities between yttrium and the trivalent lanthanides have also been discussed.     

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.     

SYNERGISTIC EXTRACTION OF ZINC(II) BY MIXTURES OF PRIMARY AMINE N1923 AND CYANEX272

ABSTRACT

The extraction of zinc(II) and cadmium(II) from chloride solution by mixtures of primary amine N1923 and Cyanex272 (HA) was studied. The synergistic effect was observed for the extraction of zinc(II) while no synergistic effect for cadmium(II), which makes it possible to separate zinc(II) and cadmium(II) with the mixtures. The results showed that zinc(II) was extracted as (RNH₃Cl)₃·ZnClA instead of ZnA₂·2HA which was extracted by Cyanex272 alone. The extraction mechanism was discussed and the formation constants and thermodynamic functions were determined. The separation factors between zinc(II) and cadmium(II) were calculated.     

Extraction of scandium(III) using ionic liquids functionalized solvent impregnated resins

Ionic liquids (ILs) functionalized solvent impregnated resins (SIRs) were prepared using IL modified Merrified resin as the polymeric supports by impregnation of extractant for extraction of Sc(III). The ILs modified Merrifield resin were prepared via covalent anchoring of imidazolium salts onto Merrifield resin. The polymeric supports with imidazolium chloride group (RCl) and imidazolium hexafluorophosphate group (RPF₆) were characterized by FTIR, TGA, and elemental analysis. It was found that RCl and RPF₆ had tunable hydrophilicity and hydrophobicity, different acid stability, and swelling behaviors in solvents. The effect of Cyanex 923 extractant or [C₈mim][PF₆] IL impregnated on RCl and RPF₆ were studied. The results showed Cyanex 923 and [C₈mim][PF₆] exhibited stronger affinity to RPF₆ than to RCl. RPF₆ with Cyanex 923 was found to be effective in Sc(III) extraction. The extraction mechanisms of SIRs containing RPF₆ and Cyanex 923 with or without [C₈mim][PF₆] were cation exchange and neutral complexation, respectively. [C₈mim][PF₆] acted as an extraction media and was involved in the cation exchanged extraction reaction. Sc(III) can be selectively separated from Tm(III), Yb(III), and Lu(III) by the SIRs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011