Equilibrium and kinetic studies of the extraction of chelated copper(II) anions with Aliquat 336

The equilibrium and kinetics of solvent extraction of Cu²⁺ from aqueous solutions containing equimolar EDTA with Aliquat 336 in n‐decanol and kerosene at 298 K were investigated. The concentrations of Cu²⁺ (8–50 mol m^?3), Cl^? (5–60 mol m^?3), and Aliquat 336 (20–100 mol m^?3) were varied. A semi‐empirical model with three parameters was proposed to describe the equilibrium behavior, in which the non‐idealities in both aqueous and organic phases were considered. Over the ranges studied, the model agreed reasonably well with the experimental data (standard deviation, 15%). The forward and backward reaction rate constants were determined as (5.31 ± 0.16)×10^?6 m^9/4 mol^?3/4 s^?1 and (2.62 ± 0.09)×10^?7 s^?1, respectively, at 298 K. An interfacial reaction mechanism was proposed, which revealed that the reaction between the chelated anions and trimeric amine molecules at the interface was rate limiting. The derived rate laws were consistent with the experimental results. © 2002 Society of Chemical Industry     

EXTRACTION OF Ni(It) BY DI-(2-ETHYLHEXlfL)PHUSPHOKIC ACID DISSOLVED IN TOLUENE

ABSTRACT

The extraction of Ni(II) from 1.0 mol-dm^-3aqueous NaNO₃medium by di-(2-ethylhexyl) phosphoric acid (HDEHP) dissolved in toluene has been studieo as a function of the total extractant concentration, the equilibrium pH and the total raetal concentration in the aqueous phase. Nickel distribution data have been interpreted in terms of the formation of NiR₂(HR)₂, and NiR₂species in the organic phase in the low pH range anc by the formation of Na-HUEHP micelles, due to the neutralization of the reagent in the organic phase, and the further exchange of Na⁺by Ni²⁺in these micelles in the high pH range for each of the total extractant concentrations used.     

Aliquat 336萃取醋酸的平衡特性

选择Aliquat 336为萃取剂 ,氯仿、正辛醇和煤油为稀释剂 ,醋酸稀溶液为分离溶质 ,研究了稀释剂种类、反应剂浓度、水相 pH值、溶质在水相的浓度等因素对醋酸萃取分配系数的影响 ,分析了Aliquat 336萃取醋酸的机理 ,并在此基础上建立了描述萃取平衡的数学模型 .结果表明 :萃取结果基本符合反应剂与稀释剂的简单加和 ;稀释剂对萃取效果的影响显著 ,随Aliquat 336浓度的增大 ,氯仿和煤油为稀释剂时的萃取能力较正辛醇增加得快 ;随 pH值的变化D存在一个最大值 ,该值只与反应剂在有机相中的浓度有关 .Aliquat 336萃取醋酸存在阴离子交换和化学缔合两种机制 ,表观的阴离子交换反应平衡常数K₁在有稀释剂的条件下比纯反应剂时有所增大 ,其中氯仿的影响相对较大 ,表观的化学缔合反应平衡常数K₂ 在有稀释剂的条件下表现为 ,惰性稀释剂煤油对K₂ 的影响不明显 ,氯仿具有强化的作用 ,而正辛醇具有削弱Aliquat 336与醋酸化学缔合的能力 .     

Purification and Concentration of Xylose and Glucose from Neutralized Bagasse Hydrolysates Using 3,5‐Dimethylphenylboronic Acid and Modified Aliquat 336 as Coextractants

Abstract

Experimental trials of the extraction of xylose, glucose, and fructose from aqueous solutions were conducted using 3,5‐dimethylphenylboronic acid (DMPBA) and modified Aliquat^® 336 (MA) as combined extractants dissolved in Exxal^®10 diluent. MA was produced by contacting an Aliquat 336/Exxal 10 solution with a concentrated caustic soda solution so that the quaternary ammonium ions of Aliquat 336 would ion pair with hydroxide ions. The DMPBA/MA/Exxal 10 organic solution containing equimolar amounts of MA and DMPBA was contacted with a neutral aqueous solution containing one of glucose, xylose, or fructose and the extraction isotherms were determined. The molar ratio of DMPBA:sugar in a fully loaded organic solution was 2:1. The use of the MA instead of Aliquat 336 enabled significant proportions of the sugars to be extracted from aqueous solutions over a wide pH range (～2–11). Loaded organic solutions were stripped using aqueous hydrochloric acid solutions. Complete recovery of the sugar was possible by ensuring sufficient acidity was available in the strip solution. Solutions of MA in Exxal 10 were also found to extract sugar, although to a lesser extent than when DMPBA was included. Extraction of xylose and glucose from solutions derived from the acid hydrolysis of bagasse was performed. By varying the volumetric ratio of strip to organic phases, strip solutions with xylose concentrations up to 4× that of the original hydrolysate were produced while reducing the concentration of the undesirable acid soluble lignin by up to 90%. Hence, this process has the potential to produce high concentration monosaccharide solutions suitable for direct fermentation.     

The extraction of platinum from Pt(II) chloride solution by a quaternary ammonium compound

The fundamental aspects of the extraction and stripping of platinum (II) from its chloride solution by Aliquat 336 diluted with toluene have been studied. The extraction and stripping was at 99.5 and 97.6% equilibrium within 30 s and 20 min respectively. The percentage extraction increased slightly with decreasing hydrochloric acid concentration. In 0.1 mol dm^?3 hydrochloric acid, 1.0 volume percent Aliquat 336 in toluene could load 9.8 mmol dm^?3 of platinum (II). The percentage stripping of platinum (II) from Pt(II)-load organic solvent increased with increasing sodium bisulphite concentration. The enthalpy changes of extraction and of stripping were 12.8 and 114.9 kJ mol^?1 respectively. Both of the reactions were endothermic.     

THE SELECTIVITY OF NICKEL OVER IRON IN THE LIX63-HDNNS SOLVENT EXTRACTION SYSTEM

ABSTRACT

The effects of the aqueous phase pH and the organic phase HDNNS concentration on the distribution coefficients of Ni and Fe in pure HDNNS or mixed LIX63-HDNNS systems have been investigated. With the mixed extractants, there is antagonistic extraction of iron below pH 1.4 whereas synergistic extraction occurs above this pH. At pH 2.5 and a fixed LIX63 concentration, iron distribution increases markedly in comparison with the oxime-free system and goes through a maximum with increase in HDNNS concentration. A similar behavior is shown by nickel at both pH 1.0 and 2.5. The log D_Feversus pH plot gives a curve with a slope of two for the LIX63-HDNNS mixed system, which suggests that iron is extracted in the form of a species with an ionic charge of 2, probably Fe(OH)²⁺. The extracted complexes are proposed as Ni(H₂L)₃D₂where all three oxime molecules function as bidentate ligands, and Fe(OH) (H₂L) ₃D₂where one of the oxime molecules functions as a monodentate ligand. The Ni/Fe selectivity is high at low pH and changes mainly as a result of variations in the nickel distribution coefficient, but it is low at high pH because of the synergistic extraction of iron.     

Rates of acetate extraction from simulated waste streams in chloromycetin production

The kinetics for extraction recovery of acetate ions from simulated waste streams in chloromycetin production by Aliquat 336 (a quaternary amine) and tri‐n‐butylphosphate (TBP) in xylene were examined using a microporous membrane‐based stirred cell. The waste stream typically contained 15.4% acetic acid, 8.8% sodium acetate, and 4.7% (w/w) NaCl. The stirred cell could give intrinsic rates for formation of the complex occurring at or near the organic–aqueous interface. It was shown that the extraction rate with TBP was higher than that with Aliquat 336. The effect of temperature (288–318 K) on the reaction rate with TBP was also examined and the activation energy (54.5 kJ mol⁻¹) was obtained. © 1999 Society of Chemical Industry     

Study of lactic acid extraction with higher molecular weight aliphatic amines

Lactic acid extraction was studied with two extractants, trioctyl amine (TOA) and Aliquat 336, in three diluents (methylisobutyl ketone (MIBK), octanol and paraffin liquid). The effects of organic phase extractant concentration and aqueous phase pH on the extraction process were examined. Among the extractants, TOA was found to be a better extractant than Aliquat 336 in all the diluents. In experiments with 50% (v/v) TOA in methylisobutyl ketone, 79% lactic acid could be extracted (initial lactic acid concentration 86·96 g dm⁻³). MIBK had a profound effect on the extraction behaviour of TOA in comparison with octanol and paraffin liquid while none of the diluents affected the extraction with Aliquat 336. The extraction of lactic acid was favoured at low pH. The toxicities of TOA and the diluents to Lactobacillus rhamnosus NRRL B445 were also studied. While TOA was found to be highly toxic at the molecular and the phase level, the paraffin liquid was totally non-toxic. The extraction of glucose and yeast extract by TOA and the diluents used was found to be low, which thus enables the selective extraction of lactic acid. © 1998 SCI     

Phase-transfer promotion of hydrodechlorination of chlorophenoxy-pesticides over Pd/C and Raney-Ni

Hydrodechlorination of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), pentachlorophenol (PCP), and p-chlorobenzoic acid with hydrogen gas over 5% Pd/C or Raney-Ni was studied in different liquid phase systems: (1) ethanol or ethanol–aqueous KOH; (2) in the multiphase system, composed by an organic phase and aqueous KOH and containing a quaternary ammonium salt (Aliquat 336). Under mild conditions (50 °C and atmospheric pressure of hydrogen) quantitative hydrodechlorination of 2,4,5-T is achieved in 1–4 h over Raney-Ni or Pd/C in the multiphase system or in the ethanol–aqueous KOH solution. PCP reacts selectively giving the dechlorinated phenolate in several hours in the system made of aqueous KOH (with Raney-Ni or Pd/C) or in several minutes in the presence of a small amount of Aliquat 336 solution in isooctane (1–4 molar% of Aliquat 336), where Aliquat 336 promotes the phase-transfer of polychlorinated anion. The reaction rates versus conditions, process localization, and the role of the ionic liquid environment are discussed.     

Permeation of Chromium(VI) and Rhenium(VII) Oxyanions through Liquid Organic Membranes Facilitated by Quaternary Ammonium Chlorides

Abstract

An experimental investigation is presented on the facilitated transport of Cr(VI) and Re(VII) oxyanions from aqueous solution into and through organic solutions of quaternary ammonium chlorides as mobile carriers of anions. Trimethyl tallow ammonium chloride (Aliquat 26), dimethyl dicoco ammonium chloride (Aliquat 221), and methyl tricapryl ammonium chloride (Aliquat 336) from General Mills Chemicals have been investigated. Effects of both anions and mobile carriers as well as the pH of feed aqueous solution and mixing rate on the course of metal permeation have been established. The hydrophobicity and nucleophilicity of a quaternary ammonium chloride were found to be the key factors influencing the transport of Cr(VI) and Re(VII) anions through bulk and emulsified liquid organic membranes. The permeation of perrhenates was much faster than that of chromates. Fast and effective separation was determined to be possible for rhenium from chromium in aqueous solution by means of facilitated transport of their oxyanions across liquid surfactant membranes.     

Trivalent Lanthanide/Actinide Separation Using Aqueous-Modified TALSPEAK Chemistry

TALSPEAK is a liquid/liquid extraction process designed to separate trivalent lanthanides (Ln³⁺) from the minor actinides (MAs) Am³⁺ and Cm³⁺. Traditional TALSPEAK organic phase is comprised of the monoacidic dialkyl bis(2-ethylhexyl)phosphoric acid extractant (HDEHP) in diisopropyl benzene (DIPB). The aqueous phase contains a soluble aminopolycarboxylate diethylenetriamine-N,N,N’,N”,N”-pentaacetic acid (DTPA) in a concentrated (1.0–2.0 M) lactic acid (HL) buffer with the aqueous acidity typically adjusted to pH 3.0. This process balances the selective complexation of the actinides by DTPA against the electrostatic attraction of the lanthanides by the HDEHP extractant to achieve the desired trivalent lanthanide/actinide group separation. In this study, the aqueous phase has been modified by replacing the lactic acid buffer with a variety of simple and longer-chain amino acid buffers. The results show successful trivalent lanthanide/actinide group separation with the aqueous-modified TALSPEAK process at pH 2. The amino acid buffer concentrations were reduced to 0.5 M (at pH 2), and separations were performed without any effect on phase-transfer kinetics. Successful modeling of the aqueous-modified TALSPEAK process (p[H⁺] 1.6–3.1) using a simplified thermodynamic model and an internally consistent set of thermodynamic data is presented.     

THE EXTRACTION OF SOME BASE METAL IONS BY CYANEX 30L CYANEX 302 AND THEIR BINARY EXTRACTANT MIXTURES WITH ALIQUAT 336

ABSTRACT

The extraction behaviour of Cyanex 301, Cyanex 302 and their binary extractant mixtures with Aliquat 33b towards copper(II), zinc(II), iron(III), iron(II), cobalt(II), nickel(II) and manganese(Il) is indicated. The extraction data were collected from sulphate solutions with acidities ranging from pH 10 to 8 mol/dm³ sulphuric acid. Cyanex 301 is a more efficient extractant than Cyanex 302 and is able to effect extraction at greater acidities. In combination with the organic base Aliquat 336 the extraction power of these extractants is lowered and in some cases the extraction is suppressed appreciably. However, the suppression of extraction can be useful in metal separation and affords greater control over the back-extraction. The suppression is ascribed to the high stability of the acid-base couple which must dissociate in order to effect extraction.     

Sensitive Colorimetric Detection of Explosive 2,6‐Bis(picrylamino)pyridine after Preconcentration by Dispersive Liquid‐Liquid Microextraction

An experimental investigation for sensitive spectrophotometric detection of explosive, 2,6‐bis(picrylamino)pyridine (BPAP) using dispersive liquid‐liquid microextraction was carried out. Based on this procedure, which is a dispersive‐solvent‐free technique, the extractant is dispersed in the aqueous sample solution using Aliquat 336 (acted as disperser agent and carrier to extraction solvent) and monitored with microvolume UV/Vis spectrophotometer. The effect of different variables such as pH, concentration of sodium hydroxide, type and volume of extraction solvent, concentration of Aliquat 336 solution and coexisting substances were systematically investigated and optimized. Interference tests showed that the developed method has a good selectivity and could be used conveniently for determination of explosive analyte. The proposed method is capable of determining BPAP over a range of 2.0–150.0 ng mL⁻¹ with a limit of detection 1.0 ng mL⁻¹. Relative standard deviations (RSD) for 20.0 and 80.0 ng mL⁻¹ of BPAP were 3.3 and 1.2 % (n=10), respectively. This colorimetric method was applied to determine BPAP in different water and soil samples.     

Uranium Solvent Extraction and Separation From Vanadium in Alkaline Solutions

Quaternary amine could be used to extract uranium from alkaline leach solutions, but third phase formation prevented its application. In this paper, isodecanol was used as the modifier for Aliquat 336 in Shellsol D70 to extract uranium from a carbonate leach solution. The formation of third phase was eliminated. More than 98% of uranium was extracted using 3% (w/v) Aliquat 336 and 3% (w/v) isodecanol in Shellsol D70 from a carbonate leach solution containing 95 mg/L U and 25 mg/L V at pH 10.3 and room temperature in a single contact. The separation factor of uranium over vanadium increased with increasing pH of the auqueous solution and reached 280 at pH 11, indicating a good separation of the two metals. The co-extracted vanadium was scrubbed from the loaded organic solution at pH 11 using a solution containing 50 g/L Na₂CO₃. Over 90% of uranium was stripped from the loaded organic soluiton using an acidic solution containing 150 g/L ammonium sulphate in a single contact. It was also found that to obtain high uranium extraction, the chloride concentration should be controlled to less than 1 g/L in the aqueous phase.     

Nondispersive Extraction of Cr(VI) with Aliquat 336: Influence of Carrier Concentration

Abstract

Kinetic experiments on the extraction of Cr(VI) with Aliquat 336 performed in hollow fiber modules and in the 1% (v) ≤ Aliquat 336 ≤ 10% (v) and 10 g/m³ ≤ Cr(VI) ≤ 500 g/m³ range of concentrations have been successfully modeled by means of the integration of the mass conservation equation and associated boundary conditions. Different values of the mass transport coefficient through the organic membrane have been obtained depending on the total carrier concentration.     

Solvent Extraction Studies of Zinc and Cadmium with Aliquat 336-S in Aqueous Chloride Solutions

Abstract

New solvent extraction systems have been developed for the extraction of zinc and cadmium from aqueous chloride solution using Aliquat 336-S dissolved in the nonpolar solvents heavy aromatic naphtha and xylene as the extractant. Moderately high concentrations of the metalions (1 mg/ml zinc and 2 mg/ml Cd) can be extracted quantitatively from acid solutions with an equal volume of 5% Aliquat 336-S solution in 15 sec. Both zinc and cadmium can be stripped from the organic phase with a series of aqueous stripping solutions. When comparing zinc and cadmium, cadmium is the easier to extract and the more difficult to strip under the same experimental conditions.     

Liquid-Liquid Extraction of Zinc with Aliquat 336-S-Br from Aqueous Bromide Solutions

Abstract

A new solvent extraction system has been developed for zinc in aqueous bromide solution using Aliquat 336-S-Br-xylene solution as an extractant. A 1 mg/ml zinc solution is extracted essentially quantitatively with an equal volume of 5% Aliquat 336-S-Br-xylene solution in 15 sec. The extracted zinc can be stripped from the nonaqueous layer with a series of aqueous solutions including Na₂SO₃ (≥m 1.0 M) NaOH (≥m 0.5 M), NH₃ (≥m 0.5 M), ethylenediamine (≥m 0.3%), and EDTA (≥m0.5%). The extraction is quantitative only from acidic solutions. High aqueous to organic phase ratios can be utilized without loss of extraction efficiency.     

Separation of Iron,Cobalt, Nickel,and Cadmium in Aqueous Acid Halide Solution Using Aliquat-Foam Columns

Abstract

Polyurethane foam loaded with Aliquat 336 was prepared. The suitability of the prepared reagent foam for the separation of various relative concentrations of iron and cobalt in acidic aqueous solutions was confirmed using the static technique. The separation of other metal couples was achieved on the basis of similar ideas. Columns packed with the Aliquat foam were successfully used in the separation of iron or cadmium from cobalt and nickel. The foam column performance proved quite reasonable, and the application of relatively high flow rates (10 mL/min) was found to be possible.     

Investigation of electrospun and film‐cast PVC membranes incorporated with aliquat 336 for efficient Cd extraction: A comparative study

This article was aimed to investigate the cadmium extraction behaviors of the two different polyvinyl chloride membranes incorporating Aliquat 336—electrospinning and film‐casting. An optimal investigation condition for membranes used in the extraction process was produced at 25 kV with 10 cm tip‐to‐collector distance. Membranes were electrospun for 8 h at 200 μL/h. Membrane extraction studies were carried out using a 127 mg/L Cd(II) solution. Scanning electron microscope (SEM) images revealed differences in fiber diameters and membrane morphology. The addition of Aliquat produced very fine fibers (7–722 nm) resulting Brunauer‐Emmett‐Teller (BET) surface areas of 4.67–11.3 m²/g for electrospun membranes and 1.70–5.44 m²/g for film‐casted membranes. Extraction studies using membranes with different levels of Aliquat (0–40% w/w) revealed that the cadmium extraction performance of electrospun membranes was significantly better than conventional film‐cast membranes. For 40% Aliquat 336, with an initial concentration of 127 mg/L Cd, the cast membrane extracted down to concentration to 115 mg/L as compared to electrospun membrane, which extracted down to 88 mg/L within 40 h. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

反胶团萃取蛋白质特性的研究

实验将一种阴离子表面活性剂（AOT）和一种阳离子表面活性剂（Aliquat336）分别溶于异辛烷（isooctane）中，构成了两种不同的反胶团体系．通过用两种不同的反胶团溶液萃取六种蛋白质的实验，研究了水相pH值及离子强度对反胶团体系中水含量Wo和蛋白质萃取率影响的规律．实验发现不论哪种反胶团体系，水相pH值对Wo的影响都不大，但pH值却对蛋白质萃取率有很大的影响，对AOT反胶团体系而言，随着pH值的降低，蛋白质的萃取率升高；对Aliquat336反胶团体系而言，随着水相pH值的降低，蛋白质的萃取率下降．随着离子强度的增大，AOT反胶团体系的水含量大幅度地降低；而对Aliquat336体系水含量的影响很小，但水相离子强度对蛋白质萃取率的影响是相同的，随着离子强度的增大，两种体系对蛋白质的萃取率均下降。