二（2-乙基己基）磷酸/磷酸三丁酯复合萃取剂协萃对氨基苯甲酸

为强化两性官能团化合物的萃取分离性能,以对氨基苯甲酸（PABA）为被分离溶质,二（2-乙基己基）磷酸（D2EHPA）/磷酸三丁酯（TBP）/正庚烷的混合物为萃取剂进行了萃取平衡特性的研究,考察了溶液的pH值、D2EHPA浓度、TBP浓度对于萃取平衡的影响,建立了复合萃取剂协同萃取PABA的萃取平衡分配系数的表达式.结果表明,D2EHPA/TBP/正庚烷复合萃取剂萃取PABA具有明显的协萃效应,协萃机理为D2EHPA及TBP分别与PABA的Lewis碱性官能团（—NH2）和Lewis酸性官能团（—COOH）缔合形成亲油性更强的萃合物,且D2EHPA与TBP的浓度差异越小,协萃效应越明显.根据萃取平衡分配系数表达式拟合求取了表观萃取平衡常数,复合萃取剂的值远大于D2EHPA、TBP单独作为萃取剂的值,进一步证明了本文提出的协萃机理.     

Liquid–Liquid Extraction of Lithium Ions Using a Slug Flow Microreactor: Effect of Extraction Reagent and Microtube Material

Lithium ions were extracted from aqueous solutions into cyclohexane containing di-(2-ethylhexyl)phosphoric acid (D2EHPA) through slug flow in millimeter-diameter glass and polytetrafluoroethylene (PTFE) tubes. The PTFE tube produced a higher initial mass transfer coefficient than the glass tube by increasing internal circulation in the organic phase, and maintained its specific surface area. Slug flow occurred in the PTFE tube when the interfacial tension between the aqueous and organic phases exceeded 50–55 mN/m, which increased the rate of extraction owing to increased circulation in both phases. The addition of tributyl phosphate (TBP) enhanced the extraction efficiency, but did not affect the extraction rate.     

Synergistic extraction and separation of Fe(III) and Zn(II) using TBP and D2EHPA

Waste chloride pickle liquors from hot-dip galvanizing plants, steel plants and flue dust contain reasonable amounts of heavy metals such as Zn, Cr, Ni, etc. Iron is invariably associated with most of these materials and comes into solution during leaching. Thus, the synergistic extraction of zinc(II) and iron(III) from leach solutions in tri-n-butyl phosphate (TBP)–di(2-ethylhexyl) phosphoric acid (D2EHPA) system diluted in kerosene was investigated. The Zn and Fe concentrations in the leach liquor used in the present study were 2 g/L. Experiments were carried out in the pH range of 0.5–4.0, temperature of 25°C, using sole D2EHPA, sole TBP and D2EHPA–TBP mixtures at different ratios. Results showed that the co-extraction of zinc(II) and iron(III) increased with increasing equilibrium pH using D2EHPA. It is demonstrated that the mixtures of TBP and D2EHPA are more efficient and selective than D2EHPA alone. At low pH values, the separation factor is low when pure D2EHPA is used as an extractant; however, using TBP as a synergist, the separation factor increases and results in a better separation of zinc from iron. Increasing TBP to D2EHPA ratios in the organic phase caused a slight shift to the right in the extraction isotherm of iron and a marked shift to the right in the extraction isotherm of zinc, and the maximum separation factor of 13.3 × 10³ was achieved at a TBP to D2EHPA volume ratio of 4:1 (0.58 M TBP: 0.12 M D2EHPA). Furthermore, the effect of equilibrium pH, organic to aqueous phase ratio and Cl^? concentration on the selective extraction was investigated. Using two extraction stages at the O/A ratio of 2:1 and pH_e (equilibrium pH) of 3 and 1 for zinc and iron, respectively, 99% of zinc(II) and 96.25% of iron(III) were extracted.     

Solvent extraction modeling of Ce/Eu/Y from chloride media using D2EHPA

End-of-life fluorescent lamps are becoming essential in the rare earths (REEs) field and suppose a feasible secondary source for getting them, reducing thus their supply risk. Considering the proved viability of the cationic extractants, the present study aims at establishing a solvent extraction model using di-(2-ethylhexyl)phosphoric acid (D2EHPA) not only based on the individual Ce, Eu, and Y behavior in chloride media, but also bearing in mind the competitive extraction of these metals in Ce/Eu/Y mixtures, depending on the media variables. Furthermore, the model allow determining the optimal REEs separation conditions. The results disclose that Y could be separated from the mixture using 0.1 mol/L D2EHPA, acidity above of 3 mol/L of protons and chloride concentrations higher than 4 mol/L.     

Efficacy of tri-n-octylamine,tri-n-butyl phosphate and di-(2-ethylhexyl) phosphoric acid for reactive separation of protocatechuic acid

ABSTRACT

Owing to its chemical and pharmacological significances, the efficacy of reactive separation of protocatechuic acid (0.001–0.01 kmol m^?3) from aqueous stream by means of tri-n-octylamine (TOA), di-2-ethylhexyl phosphoric acid (D2EHPA) as well as tri-n-butyl phosphate (TBP) in octanol has been investigated, in terms of extraction efficiency, loading ratio, equilibrium complexation constants, and distribution coefficients. Extraction ability was obtained in the order TOA (91.2%) > TBP (88.64%) > D2EHPA (86.43%). In all cases, 1:1 protocatechuic acid:extractant complex is obtained. Further, diffusion coefficients, number of stages for extraction systems, and relative basicity model were used for relating the efficacy.     

二(2-乙基己基)磷酸萃取L-色氨酸

以二 (2 -乙基己基 )磷酸 (D2EHPA) -正辛烷 (体系A)及D2EHPA -正辛醇 +正辛烷 (体系B)萃取L -色氨酸为对象 ,研究了D2EHPA浓度、L -色氨酸初始浓度、稀释剂组成以及pH值对萃取平衡分配系数的影响 .结果表明 ,在实验研究涉及的pH值 (1.0     

二（2-乙基已基）磷酸萃取氨基苯甲酸的平衡特性

A series of extraction equilibrium experiments for aminobenzoic acid with di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-octane or 1-octanol was carried out. The effects of aminobenzoic acid concentration,D2EHPA concentration and pH on the distribution ratio were discussed in detail. The infrared spectra of the organic phase loaded with solute illustrated that pH had little effect on the structure of the complex formed. There proceed ion association and cation-exchange.reaction in the extraction. An expression of the equilibrium distribution was proposed.     

Extraction and Stripping Behavior of Iron (III) from Phosphoric Acid Medium by D2EHPA Alone and Its Mixtures with TBP/TOPO

In the present study an attempt has been made to understand the extraction and stripping behavior of iron (III) with D2EHPA alone and its mixture with TBP or TOPO in phosphoric acid medium. Effect of variables such as concentrations of iron (III), phosphoric acid, and phosphate in the aqueous phase, D2EHPA, TBP, and TOPO concentrations in the organic phase and temperature on the extraction process has been studied. The extraction of iron (III) decreased with increase in phosphoric acid concentration. The increase in D2EHPA concentration increased the extraction of iron (III). The presence of TOPO or TBP with D2EHPA showed antagonism. The increase in temperature decreased the extraction of iron (III) with D2EHPA alone and its mixture with either TOPO or TBP showing the exothermic nature of the extraction reaction. The stripping of iron (III) by various reagents followed the order: oxalic acid > phosphoric acid > hydrochloric acid > sulphuric acid > mixture of sulphuric and hydrofluoric acids > ascorbic acid > citric acid irrespective of extraction systems. Higher temperature favors the stripping. The effect of diluents on iron (III) extraction has also been studied. The mechanism of extraction has been explained in the light of the results obtained.     

Simple separation method of Zn(Ⅱ) and Cd(Ⅱ) from brine solution of zinc plant residue and synthetic chloride media using solvent extraction

In this work, the possibility of separation of Zn~(2+) and Cd~(2+) metal ions from chloride(brine) solutions was examined. For this purpose, simple solvent extraction(SX) experiments by di-2-ethylhexyl phosphoric acid(D2EHPA)in kerosene as a diluent was performed on synthetic and industrial chloride solution obtained from brine leaching of zinc filter cakes(by-product of zinc hydrometallurgical processing). The optimal conditions for separation were determined. The zinc extraction efficiency was 99% with negligible co-extraction of cadmium.Therefore, a high ΔpH_(0.5) value for Zn(Ⅱ) and Cd(Ⅱ) was achieved. FT-IR and slope analysis indicated that ZnClA·3HA and CdClA·3HA species were probably extracted.     

Selective and Synergistic Extraction of Nickel from Simulated Cr-Ni Electroplating Bath Solutions using LIX 63 and D2EHPA as Carriers

The main goal of the present study is to explain synergistic extraction of nickel from simulated Cr-Ni electroplating bath solutions (SEBS) using 5,8-diethyl-7-hydroxydodecane-6-one oxime (LIX 63) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) as extractants by emulsion liquid membrane (ELM) technique. The importance of membrane composition and aqueous phase properties on nickel extraction percentage has been highlighted for the selective extraction of nickel. Some important parameters like acid concentration, stripping solution type and concentration, mixing speed, extractant concentrations, phase ratio, and surfactant concentration was studied to improve the extraction and stripping efficiencies. Higher than > 99% of nickel was recovered at optimum conditions within 6 min. The higher separation factors (β_Ni/Cr) were obtained as 580. As a result, the nickel extraction kinetic with D2EHPA has been defined as faster than LIX63. So, the kinetic transport of nickel mainly depends on LIX63 than D2EHPA. According to these results, D2EHPA behaves as a synergistic extractant in the present extraction mechanism.     

Extraction of rare earths using mixtures of sec-octylphenoxy acetic acid and organophosphorus acids

The extraction of rare earths from nitrate medium using three organophosphorus acids, 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HEHEHP), di-(2-ethylhexyl) phosphoric acid (D2EHPA), bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272), and their mixtures with sec-octylphenoxy acetic acid (CA12) has been studied in detail. The mixtures have different extraction effects on various rare earths. Synergistic extraction effects are only found when light rare earths and yttrium (III) are extracted with mixtures of D2EHPA and CA12. The possibilities of separating the rare earths with these mixtures are investigated according to the extractabilities. It is feasible and advantageous to separate yttrium (III) from the lanthanoids (III) with HEHEHP + CA12 and D2EHPA+CA12 mixtures at proper extractant ratios. The separation of yttrium (III) from heavy rare earths is also possible with mixtures of Cyanex272 and CA12.     

从石煤酸浸液中萃取钒的实验研究

以陕西山阳石煤钒矿作为研究对象,实验研究了磷酸二异辛酯(P204)对硫酸浸出溶液体系中钒的萃取工艺。主要考察了P204体积分数、pH值、萃取时间、萃取级数及有机相与水相体积比等因素对钒萃取率的影响。确定了萃取的最佳工艺参数:P204体积分数20%,磷酸三丁酯(TBP)5%,磺化煤油75%,萃取平衡pH值在2.5左右,相体积比为1∶5,萃取时间为5 min,萃取级数为5级。在此条件下萃取含钒2.965 8 g/L溶液,萃取率可达98.57%。     

Separation and Recovery of Light Rare-Earths from Chloride Solutions using Organophosphorus based Extractants

In this paper, separation possibilities of light rare-earths (LREs), Ce, La, Nd, and Pr with three acidic organophosphorus extractants such as TOPS 99 (an equivalent of di-2-ethylhexyl phosphoric acid, D2EHPA), PC 88A(2-ethylhexylphosphonic acid mono-2-ethylhexyl ester), and Cyanex 272 (Bis(2,4,4-trimethylpentyl)phosphinic acid) from synthetic chloride solutions of monazite at three initial pH values has been investigated. The composition of synthetic leach liquor is Ce ? 5.4 g/L, La ? 3.12 g/L, Nd ?1.35 g/L, and Pr ? 0.475 g/L at pH 2.0. Using sodium hypochlorite and sodium hydroxide, cerium was precipitated as ceric hydroxide quantitatively. Among the three investigated extractants, TOPS 99 showed better separation factors towards LREs. Therefore, 0.7 mol/L TOPS 99 has been employed for the separation of Nd, and Pr from La in 3-stages at an aqueous to organic phase ratio of 4:1 and pH 2.0. Raffinate contains 2120 mg/L La, 41 mg/L of Nd, and 17 mg/L of Pr corresponding to an extraction efficiency of 32.1%, 96.4%, and 96.2%, respectively. La from loaded organic phase was scrubbed with 9182 mg/L Nd solution and achieved a scrubbing efficiency of 98.2%. 1 mol/L HCl is used for quantitative stripping. A process flowsheet for the separation and recovery of LREs was presented.     

Extraction and recovery of rhodamine B,methyl violet and methylene blue from industrial wastewater using D2EHPA as an extractant

The extraction behavior of cationic dyes namely rhodamine B (RB), methyl violet (MV) and methylene blue (MB) from industrial wastewater has been investigated using di-(2-ethylhexyl) phosphoric acid (D2EHPA) in hexane as a carrier. The extraction of cationic dyes increases with decreasing feed phase pH and increasing D2EHPA concentration in organic phase. The stripping percentage of dyes using acetic acid as the stripping agent from loaded D2EHPA was found to increase with increasing acid concentration. 98% stripping efficiency of dyes was achieved with 8.5 mol/L acetic acid solution at an organic:aqueous phase ratio (O/A) of 2:1. Parameters examined include D2EHPA concentration, effect of diluents, effect of pH, effect of initial dye concentration, equilibration time, and various stripping agents, aqueous to organic phase ratio in extraction and organic to aqueous phase ratio in stripping.     

Vanadium(IV) solvent extraction enhancement in high acidity using di-(2-ethylhexyl)phosphoric acid with [Cl−] present: an experimental and theoretical study

Separation of vanadium from black shale leaching solution at low pH is very meaningful, which can effectively avoid the generation of alkali neutralization slag and the resulting vanadium loss. In this study, coordination mechanism of vanadium in acid leaching solution at low pH was investigated with the intervention of chloride ions. Under the conditions of pH 0.8, di-(2-ethylhexyl)phosphoric acid concentration of 20%, phase ratio of 1:2, and extraction time of 8 min, the vanadium extraction could reach 80.00%. The Fourier transform infrared and electrospray ionization results reveal that, despite the fact that the chloride ion in the leachate could significantly promote vanadium extraction, the chloride ion does not enter the organic phase, indicating an intriguing phenomenon. Among Cl⁻–V, SO₄²⁻–V, and H₂O–V, the V–Cl bond is longer and the potential difference between coordinate ions and vanadium is smaller. Therefore, VO²⁺ gets easily desorbed with chloride ions and enter the organic phase. At the same time, the hydrogen ions of di-(2-ethylhexyl)phosphoric acid also enter the water phase more easily, which reduces the pH required for the extraction reaction.     

采用不同载体的中空纤维更新液膜Cu(Ⅱ)传质的研究(英文)

The extraction ability of organophosphorus extractant D2EHPA (di-2-ethylhexyl phosphoric acid) and hydroximic extractant Lix984N are investigated by the extraction equilibrium experiments. Effects of carrier concentration and organic/aqueous volume ratio on the mass transfer of hollow fiber renewal liquid membrane (HFRLM) are studied. Results show that, in the extracting process, kerosene and n-heptane are more suitable than methyl-isobutyl ketone, butylacetate and benzene as the diluents of D2EHPA or Lix984N. The favorable feed pH is 4.4 for D2EHPA and 2.6 for Lix984N. The mass transfer flux of HFRLM increases with carrier concentration and finally reaches a plateau. The mass transfer flux and the overall transfer coefficient increase with the or-ganic/aqueous volume ratio, reach the maximum and then decrease.     

Synergic Extraction of Folic Acid with Di(2-ethylhexyl) Phosphoric Acid and Amberlite LA-2

The influences of extractants concentrations and solvent polarity on the efficiency of folic acid separation by synergic extraction with Amberlite LA-2 and di(2-ethylhexyl) phosphoric acid (D2EHPA) mixture have been analyzed. The results indicated the formation of an interfacial compound which includes one molecule of folic acid and one of D2EHPA, the hydrophobicity of this compound being increased by solvation with Amberlite LA-2 molecules. The number of aminic molecules participating in the interfacial complex formation is controlled by solvent polarity and D2EHPA concentration, decreasing from 3 to 1 with the increase of these two parameters. The results indicated that the most important synergic effect corresponds to the extractants mixture dissolved n-heptane, at low D2EHPA concentration in the organic phase (5 g/l).     

利用磷酸三丁酯在硫酸-磷酸体系中萃取净化低浓度湿法磷酸工艺的研究

研究了利用磷酸三丁酯在硫酸-磷酸体系中萃取净化低浓度湿法磷酸工艺,获得了萃取性能较好的萃取体系。实验表明,稀释剂（煤油）添加量为磷酸三丁酯与稀释剂总质量的10％时,萃取净化较佳工艺条件为：萃取相比4,萃取温度40℃,搅拌时间15min,硫酸添加量为原料湿法磷酸的1％;SO42^-去除率-80％,Fe、Al去除率99％以上,P2O5,损失率约60％,所得净化稀磷酸P2O5,7．5％,可作为热法磷酸吸收剂。     

钨钼混合溶液萃取平衡的测定与研究

采用一套溶剂萃取平衡测定装置,在酸性介质中,选择D2EHPA[二－（2－乙基己基）磷酸酯]为萃取剂,煤油为稀释剂,仲辛醇为改质剂,EDTA为络合剂,系统完整地测定了不同条件下两种浓度范围的含大量钨和少量钼的溶液的钨钼萃取分离平衡数据,分析和研究了各种因素对钨钼萃取分离的影响．分别用萃取平衡的经验模型和化学模型对该萃取体系进行了关联计算,得出了一套可以在工业计算中使用的经验模型和化学模型,为工业过程设计、工程优化和计算机模拟提供了基础．     

Solvent extraction used in industrial separation of rare earths

The total reflux method as applied to the separation of rare earth elements is outlined with reference to extractants Versatic 911, tributyl phosphate and di-2-ethylhexyl phosphoric acid. Industrial solvent extraction processes are described for the production of pure compounds of lanthanum, praseodymium, neodymium, samarium, europium, gadolinium and yttrium.