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.     

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.     

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.     

Solvent extraction of copper in a reciprocating plate column

Equilibrium data for the distribution of copper between an aqueous solution and a 20% solution of di-(2 ethyl hexyl) phosphoric acid in kerosene has been obtained by shake-flask experiments. The capacity of the organic phase for copper is greatly improved when the ammonium salt of D2EHPA is used. The performance of a 5 cm diameter Karr reciprocating plate extraction column for continuous counter-current extraction of copper by ammoniated D2EHPA has been measured. The results, expressed as heights of a transfer unit, have been compared with data for a non-metallic system (kerosene/acetic acid/water) in the same column. The lowest H.T.U. values measured were 43 cm for copper transfer and 23 cm for acetic acid transfer, with the difference being attributed mainly to the lower molecular diffusivity in the copper/D2EHPA system.     

Production of high purity rare earth mixture from iron-rich spent fluid catalytic cracking (FCC) catalyst using acid leaching and two-step solvent extraction process

Acid leaching and a two-step solvent extraction procedure were developed to produce high purity mixture of La and Ce from iron-rich spent FCC catalyst discharged from Dzung Quat refinery (Vietnam). Acid leaching of the spent catalyst with 2M HNO₃ and a solid-to-liquid ratio of 1/3 at 80 °C in 1 h dissolved almost 90% of La while 12% of Al and 25% of Fe were transferred to the leachate. The extraction of RE metals and main impurities such as Al and Fe by a mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) was investigated. Experiments showed that it was necessary to remove Fe before extracting RE and the optimum extraction conditions for a high recovery of RE while 0% of Al extraction were pH-1, contact time=10min, and D2EHPA/TBP volume ratio= 4: 1. At these conditions, the extraction yields of La(III) and Ce(III) were 72% and 89%, respectively. A two-step solvent extraction was developed to achieve a high purity of RE mixture, which included (1) the removal of impurity Fe by 25% (v/v) diisooctyl phosphinic acid (DiOPA) in n-octane for 140 min, (2) the extraction of rare earths by a mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) in n-octane for 10 min without the need for adjusting the pH of the leaching solution.     

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).     

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.     

EXTRACTION OF METAL IONS WITH DZEHPA FROM MIXED AQUEOUS-ORGANIC MEDIA

Extraction of metal ions from the aqueous-organic solution containing dimethyl formamide(DMF), dimethyl sulfoxide(DMSO) and acetonitrile(AN) was investigated by using di-2-ethylhexyl-phosphoric acid(D2EHPA) as an extractant. The organic phase was a binary solution of D2EHPA and n-hexane, or D2EHPA and toluene, while the polar phase was a three component solution of metal salt, non-aqueous solvent and water. The extracted metal ions were Cr(III), Fe(III), Al, Cu, Ni, Co(II), Mg and Ag.

The extraction behaviors may be explained by the solvation ability of non-aqueous solvents, the decrease in distribution of the extractant and extract into the organic phase, and the interaction between the extractant and non-aqueous solvents due to the dissolution of non-aqueous solvents in the organic phase.     

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.     

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．     

Investigating the Synergistic Effect of D2EHPA and Cyanex 302 on Zinc and Manganese Separation

The synergistic effect of Cyanex 302 on the extraction of zinc and manganese with D2EHPA in sulfate media was investigated. Experiments were carried out in the pH range of 1.0–5.0, temperature of 23, 40, and 60°C with sole D2EHPA and Cyanex 302 as extractant and D2EHPA to Cyanex 302 ratios of 1:3, 1:1, and 3:1. The experimental results showed that the co-extraction of zinc and manganese increased with increasing equilibrium pH and temperature. Increasing the D2EHPA to Cyanex 302 ratio in the organic phase, caused a left shifting of the extraction isotherm of zinc and a right shifting of the extraction isotherm of manganese. Thus, a better separation of zinc over manganese was achieved. At low pHs, the separation factor is low when pure D2EHPA is used as an extractant; however, using Cyanex 302 as a synergist, the separation factor increases and results in a better separation of zinc from manganese. Stoichiometric coefficient of zinc for single D2EHPA and Cyanex 302 and their mixture was calculated to be close to 6.     

萃取剂相对酸(碱)度对极性有机物络合萃取平衡的影响

选择萃取剂的相对酸（碱）度为萃取剂的特征参数,以三种常用的络合萃取剂,TOA／正辛醇、TRPO/煤油、D2EHPA/煤油为研究对象,测定TOA和TRPO相对于HCI的pKa.Bs,D2EHPA相对于NaOH的相对酸度（pkAs）物性参数,分别结合萃取有机羧酸、有机胺的平衡特性,进一步研究萃取剂的相对酸（碱）度与络合萃取平衡的关系。结果表明,萃取剂的相对酸（碱）度与萃取剂的浓度有关,并由此直接影响络合萃取平衡的结果,是影响络合萃取平衡的重要因素：提出了影响萃取平衡的三个重要因素：溶质的亲油性、溶质的电性参数、络合剂的相对碱（酸）度,并在不同体系下建立了表观络合萃取平衡常数与这三参数的关联式,关联精度是相当满意的,可以很好地预测络合萃取平衡的特性。     

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.     

Sedimentation behavior of droplets for the reactive extraction of zinc with D2EHPA

The sedimentation characteristics of the reactive standard test system zinc + D2EHPA are investigated in this work. Experiments with single droplets rising in a stagnant continuous phase have been carried out. The concentration of D2EHPA, zinc, and sulfuric acid as well as the diameter of the droplets are varied. The velocity of droplets is observed to be transient for several seconds. High mass‐transfer rates increase the velocity of single droplets for the case of reactive extraction whereas for physical systems contrary behavior is observed. Therefore, droplets seem to behave principally different in reactive and physical extraction. This is explained by the interfacially active properties of D2EHPA. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

Synergistic Effect of D2EHPA and Cyanex 272 on Separation of Zinc and Manganese by Solvent Extraction

The effect of bis-2-ethylhexylphosphoric acid (D2EHPA), bis (2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272), and tri-butyl phosphate (TBP) and their mixtures in various proportions for the separation and extraction of zinc and manganese from sulfate solutions were investigated. Experiments were carried out in the pH range of 0.5–5.0 at 25, 40, and 60°C. It was shown that the extraction of zinc and manganese by D2EHPA and/or Cyanex 272 can be increased by the increase in pH and temperature. The synergistic extraction and separation of zinc and manganese with a mixture of D2EHPA and Cyanex 272 was studied and the results showed that mixing the two extractants improved the extraction capacity of the mixture. Increasing the D2EHPA to Cyanex 272 ratio in the organic phase, caused a right shifting of extraction isotherms of manganese and zinc; shifting the manganese curve was more than zinc. The manganese curve had considerable right shifting with 5% D2EHPA and 15% Cyanex 272. TBP did not affect the zinc (Zn) and manganese (Mn) extraction. The stoichiometric coefficients of Zn and Mn were determined with 20% and 5% D2EHPA and 15% Cyanex 272 by applying the slope analysis method. The organic phase was stripped by sulfuric acid.     

Effect of a water-insoluble organic acid on amine extraction of acetic acid from aqueous solutions. Equilibrium studies

The effect of a water-insoluble organic acid, di(2-ethylhexyl)phosphoric acid (D2EHPA), on the extraction equilibrium of acetic acid from aqueous media with xylene solutions of tri-n-octylamine (TOA) was systematically investigated. In the absence of D2EHPA, the formulation of the extracted species in the organic phase and equilibrium constants for the formation of these species were numerically determined. Synergistic and antagonistic effects on the extraction of acetic acid were observed in the presence of D2EHPA, mainly depending on the concentration of TOA and the concentration ratio of D2EHPA to TOA. Finally, the influence of temperature on the extraction of acetic acid with TOA and/or D2EHPA was investigated.     

Removal of Cu2+ from Water Using Liquid-Liquid Microchannel Extraction

The very good extraction selectivity of Cu²⁺ from water was demonstrated with a new microchannel equipment, by employing di-(2-ethylhexyl)phosphoric acid (D2EHPA) as an extractant and kerosene as a solvent. The effects of different experimental parameters on the extraction efficiency E, the volumetric mass transfer coefficient K_La, and the entrainment were experimentally investigated. The results showed that the extraction efficiency increased with increasing temperature, extractant concentration, phase ratio (organic/aqueous), and pH. The total flow rate, phase ratio, and pH were found to have a great effect on the mass transfer, whereas the temperature and the extractant concentration showed little effect.     

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.     

Enantioselective Extraction of Racemic Mandelic Acid by Di(2‐ethylhexyl) Phosphoric Acid and Tartaric Acid Derivatives as Mixed Complex Chiral Selectors

The distribution behavior of mandelic acid (MA) enantiomers was examined in a two‐phase system containing di(2‐ethylhexyl) phosphoric acid (D2EHPA) with two tartaric acid derivatives as complex chiral selectors in n‐octanol. Factors affecting the extraction were investigated, including the structure and concentration of tartaric acid as well as the concentration of D2EHPA and D,L‐MA. The results showed that both the distribution ratio and enantioselectivity were greatly improved by using a complex chiral selector rather than using the tartaric acid derivative by itself. Finally, it was found that the formation of mixed complex chiral selectors by mixing two tartaric acid derivatives with D2EHPA can improve the capacity of enantioselective extraction.