The Effect of Foreign Ions on Separation of Hafnium from Zirconium on Diphonix® Resin

The weight distribution coefficients (λ_M) of the most often occurring in zirconium salts ions (M(II), M(III) and M(IV)) have been determined in established earlier optimal conditions for separation of zirconium from hafnium by means of Diphonix® resin. Their values range from 21 (λ_Zn(II)) to 1830 (λ_Ti(IV)) and depend on the charge of M ion as well as on its radius. For ions of the highest λ_M (Ti(IV) and Fe(III)) their influence on hafnium – zirconium separation has been studied. Ti(IV) ions at concentration of 1% (in relation to Zr) has been found to noticeably affect separation of hafnium from zirconium by means of Diphonix® resin.     

Pseudo‐Hydroxide Extraction in the Separation of Sodium Hydroxide from Aqueous Solutions Using Alkyl Phenols

Abstract

Pseudo‐hydroxide extraction of sodium hydroxide from aqueous solution using four alkyl phenols of nearly identical molecular weight in 1‐octanol at 25°C was examined to understand the effect of alkyl substituents. The order of extraction strength among the four alkyl phenols tested was 4‐tert‐octylphenol>3,5‐di‐tert‐butylphenol>2,4‐di‐tert‐butylphenol>2,6‐di‐tert‐butyl‐4‐methylphenol. A good correlation with phenol pK _a was observed, indicating that extraction strength is determined by phenol acidity, as modified by steric effects in proximity to the phenol –OH group. The effective partition ratios (P _eff) of two phenols from 1 M NaOH solution were determined, showing that the phenols remain predominantly in the 1‐octanol phase even when converted to their sodium salts. However, the hydrophobicity of the tested phenols may not be sufficient for process purposes. The equilibrium constants for the governing extraction equilibria were determined by modeling the data using the program SXLSQI, supporting the cation‐exchange extraction mechanism. The proposed mechanism consists of two simple sets of equilibria for

1. Ion‐pair extraction to give Na⁺OH^? ion pairs and corresponding free ions in 1‐octanol the phase and

2. Cation exchange by monomeric phenol molecules (HAs) to form monomeric organic‐phase Na⁺A^? ion pairs and corresponding free organic‐phase ions.

Analysis of the Processes of Extraction–Chromatographic Separation in a Cascade of Mixing–Settling Extractors

Theoretical Foundations of Chemical Engineering - An analysis of the processes of extraction separation of a mixture of components in a cascade of mixing–settling extractors operating in the...     

Investigation into the Extraction–Chromatographic Separation of a Binary Mixture in a Series of Multistage Columns

Theoretical Foundations of Chemical Engineering - The semibatch multistage extraction chromatographic separation of a binary system of components has been experimentally studied under various...     

Separation of Quercentin by Pre-dispersed Solvent Extraction

Pre-dispersed solvent extraction (PDSE) was used to extract quercentin from its diluted solution. The influences of temperature, phase volume ratio (PVR), concentration of sodium Dodecyl benzene sulphonate and pH value etc. on the extraction efficiency were examined. It is found that, compared with traditional extraction techniques under the same condition, a higher extraction productivity can be obtained by PDSE. The stability of colloidal liquid aphrons plays an important role in this process. In a certain scope, the extraction efficiency increases with PVR. Excessive amount of solvent is not much helpful. A new analytical method by using ultraviolet spectrometer to determine the concentration of quercentin is established.     

Using the Extraction–Pyrolysis Method in Synthesis of Bioactive Glass

Theoretical Foundations of Chemical Engineering - The paper focuses on synthesis of bioactive glass with tailored properties achieved by doping it with oxides of different elements. The bioglass...     

Reactive Extraction of o-Aminophenol Using Trialkylphosphine Oxide

Extraction of o-aminophenol （OAP） using trialkylphosphine oxide （TRPO） was studied with different diluents The neutral OAP was extracted using TRPO under an equilibrium pH in the range of 6-7.5, and a maximum distribution coefficient occurred. It was confirmed that the pH value and the TRPO concentration are the key factors that affect distribution coefficient. Nonpolar diluents could provide better extraction distribution coefficient for the extraction of OAP and the order is： kerosene 〉n-octanol 〉chloroform.     

Liquid–Liquid Extraction of Butanol from Dilute Aqueous Solutions Using Soybean-Derived Biodiesel

Liquid–liquid extraction (LLE) of mixtures of butanol, 1,3-propanediol (PDO), and ethanol was performed using soybean-derived biodiesel as the extractant. The composition of the mixtures simulated the product of the anaerobic fermentation of biodiesel-derived crude glycerol, which has recently been reported for the first time by the authors. Using a biodiesel: with an aqueous phase volume ratio of 1:1, butanol recovery ranged from 45 to 51% at initial butanol concentrations of 150 and 225 mM, respectively. Less than 10% of the ethanol was extracted, and essentially no PDO was extracted. The partition coefficient for butanol in biodiesel was determined to be 0.91 ± 0.097. This partition coefficient is less than that of oleyl alcohol, which is considered the standard for LLE. However, butanol is suitable for blending with biodiesel, which would eliminate the need for separating the butanol after extraction. Additionally, biodiesel is much less costly than oleyl alcohol. If biodiesel-derived glycerol is used as the feedstock for butanol production, and biodiesel is used as the extractant to recover butanol from the fermentation broth, production of a biodiesel/butanol fuel blend could be a fully integrated process within a biodiesel facility. This process could ultimately help reduce the cost of butanol separation and ultimately help improve the overall economics of butanol fermentation using renewable feedstocks.     

Hollow-Fiber Membrane Extraction of Copper from Aqueous Nitrate Media by LIX® Reagents: Comparison of Extraction Efficiency and Fractional Resistances

Abstract

Extraction of copper from nitrate/nitric acid aqueous solutions was studied using a HF Membrane Module and four LIX reagents (LIX® 860N-I, LIX® 984N, LIX® 84-I, and LIX® 65N) containing different active compounds (ketoximes and/or salicylaldoximes). Kinetic experiments varying the flow rates of both phases, aqueous and organic, and the extractant concentration were carried out to compare the extraction rate and efficiency from nitrate-aqueous media. A mathematical model based on the “aqueous extraction mechanism” in which the chemical reaction takes place in an aqueous-reaction zone was applied to determine the individual resistances of the copper mass-transfer process. It was found that the fractional resistance due to chemical reaction in the aqueous reaction zone, which varied from 92.5% to 95.8% in the order LIX® 860N-I < LIX® 984N < LIX® 84-I < LIX® 65N, controlled the total rate of the hollow-fiber copper extraction from nitrate aqueous media.     

Extraction of Parabens from Water Samples Using Cloud Point Extraction with a Non-Ionic Surfactant with β-Cyclodextrin as Modifier

A cloud point extraction process using a silicone non-ionic surfactant to extract selected parabens compounds from water samples was investigated using reversed phase high performance liquid chromatography. The cloud point extraction process, in the presence of β-cyclodextrin (β-CD) as a modifier, is a new extraction process which was optimized with five parameters, i.e. salt concentration, pH of the solution, temperature, surfactant concentration and β-CD concentration. The developed method with the β-CD modifier results in an excellent performance on detection of parabens from water samples with limits of detection in the range of 0.017–0.043 μg/L and percentage recoveries from 90.5 to 98.9 %.     

Kinetic Aspects of Copper‐LIX ® Extraction from Nitrate/Nitric Acid Aqueous Solutions

Abstract

A comparative kinetic study of the extraction of copper from nitrate/nitric acid aqueous solutions by different classes of LIX ^® reagents (LIX 984N, LIX 860N‐I, LIX 84‐I, LIX 65N) was performed. Using a Rotating Diffusion Cell, the rate constants of the chemical reactions (forward and reverse) were estimated and compared. In the case of the mixed extractant LIX 984N, a synergistic effect was observed. The values of the forward reaction constants of all the extractants were found to be an order of magnitude higher than those of the reverse reaction. The relatively low E _a ‐values prove the substantial influence of the diffusion on the extraction kinetics under the experimental conditions studied.     

Synergistic Extraction of Gallium from Sulfate Solution

A novel extractant mixture, di-2-ethylhexyl phosphate (DEHPA) plus HX, was proposed and tested for recovering gallium from sulfate solution. It was found that the extraction capacity of DEPHA for gallium from sulfate solution could be enhanced significantly due to the synergistic effect of acidic extractant HX. Gallium extraction is negligible below pH 0 and highly sensitive to pH of aqueous phase in the range from 0 to 1, and satisfactory extraction can be gained at pH>1. More than 96% Ga extraction was obtained using 15% DEHPA plus 2% HX. Although Fe (Ⅲ) was found to be extracted preferentially to Ga (Ⅲ), effective extraction of Ga (Ⅲ) was possible by reducing ferric to the ferrous state prior to extraction. A loaded organic phase containing 0.48g L-1 Ga could be produced from solution of 0.12g L-1 Ga at A/O ratio of 4 : 1 via three mixer-settler operation stages. Gallium was stripped quantitatively from the loaded organic phase with l,5mol L-1 of sulfuric acid.     

Separation and Purification of α-Cyperone from Cyperus rotundus with Supercritical Fluid Extraction and High-Speed Counter-Current Chromatography

Abstract

α-Cyperone was separated and purified for the first time from essential oil of the traditional Chinese medicinal plant Cyperus rotundus L. by high-speed counter-current chromatography (HSCCC). Essential oil was obtained by extraction with supercritical carbon dioxide under the pressure of 20 MPa and temperature of 40°C. The separation was performed in one step with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:0.2:1.1:0.2, v/v), in which the lower phase was used as the mobile phase at a flow-rate of 2.0 ml/min in the head-to-tail elution mode. A total of 60 mg α-cyperone at 98.8% purity was yielded from 0.9 g essential oil as determined by HPLC analysis. The structure of the target compound was performed by electron impact ionization mass spectrometry (EI-MS) and further conformed by comparison with an authentic sample (National Institute of the Control of Pharmaceutical and Biological Products, Beijing, China).     

Extraction of potassium from K-feldspar via the CaCl2 calcination route☆

The extraction of potassium from K-feldspar via a calcium chloride calcination route was studied with a focus on the effects of the calcination atmosphere, calcination temperature and time, mass ratio of CaCl2 to K-feldspar ore and particle size of the K-feldspar ore. The results demonstrated that a competing high-temperature hydrolysis reaction of calcium chloride with moisture in a damp atmosphere occurred concurrently with the conversion reaction of K-feldspar with CaCl2, thus reducing the amount of potassium extracted. The conversion reaction started at approximately 600 °C and accelerated with increasing temperature. When the temperature rose above 900 °C, the extraction of potassium gradually decreased due to the volatilization of the product, KCl. As much as approximately 41%of the potassium was volatilized in 40 min at 1100 °C. The mass ratio of CaCl2/K-feldspar ore significantly affected the extraction. At a mass ratio of 1.15 and 900 °C, the potassium extraction reached 91%in 40 min, while the extraction was reduced to only 22%at the theoretical mass ratio of 0.2. Optimal process conditions are as follows:ore particle size of 50–75μm, tablet forming pressure of 3 MPa, dry nitrogen atmosphere, mass ratio of CaCl2/ore 1.15:1, calcination temperature of 900 °C, and calcination time of 40 min. The XRD analysis revealed that a complex phase transition of the product SiO2 was also accompanied by the con-version reaction of K-feldspar/CaCl2. The SiO2 product formed at the initial stage was in the quartz phase at 900 °C and was gradually transformed into cristobalite after 30 min.     

Extraction of Lactic Acid Using the Polyethylene Glycol–Sodium Sulfate–Water System

Theoretical Foundations of Chemical Engineering - An extraction system based on polyethylene glycol 1500 and sodium sulfate for extracting lactic acid from aqueous solutions is proposed. The...     

Evaluation of Amberlite IRC‐718 Chelating Ion Exchange Resin in Loading‐Elution‐Regeneration Cycles for the Separation and Recovery of Strontium from Alkaline Radioactive Waste

The separation and recovery of radiostrontium from simulated alkaline reprocessing waste solution has been studied using Amberlite IRC‐718, a chelating resin containing iminodiacetic acid groups. The breakthrough behavior of strontium has been determined by conducting an extended column run. The column loading performance has been correlated with batch equilibration results. Efficient elution of loaded strontium has been achieved using dilute nitric acid. Satisfactory column performance has been demonstrated in repeated loading‐elution‐regeneration cycles. Finally, the characteristics of used resin have been determined to ascertain its efficacy for further use.     

Solid‐Liquid Extraction of Terbium from Phosphoric Acid Medium using Bifunctional Phosphinic Acid Resin,Tulsion CH‐96

Solid‐liquid extraction of terbium from phosphoric acid medium has been studied using the commercially available macroporous bifunctional phosphinic acid resin, Tulsion CH‐96. The parameters studied include equilibration time, acid concentration, amount of resin, metal concentration, temperature, loading, elution, regeneration, and recycling. In the wide range of phosphoric acid concentration 0.01–7.8 M the percent extraction of terbium decreases from 98.9% at 0.01 M to 16.0% at 1 M due to an ion‐exchange mechanism and increases to 36% at 7.8 M due to a coordination mechanism. The percent extraction increases with an increase in weight of the resin from 2.7% at 0.05 g to 80.7% at 1.2 g. Under the studied experimental conditions, the loading of Tulsion CH‐96 for terbium was determined to be 3.52 mg per gram of resin. The percent extraction of terbium increases with the increase in temperature, indicating the endothermic nature of the extraction process. Screening of various eluants suggested 1 M (NH₄)₂CO₃ as the best with an efficiency of 99.8%. The extraction behavior of commonly associated metals with terbium such as yttrium, holmium, erbium, dysprosium, ytterbium, and lutetium has been studied as a function of phosphoric acid concentration to determine the separation factors and possible separation.     

Extraction of Caprolactam from Aqueous Ammonium Sulfate Solution in Pulsed Packed Column Using 250Y Mellapak Packings

1 INTRODUCTION Caprolactam is a major ingredient in the manufacture of nylon 6 fibers. In the process of caprolactam production, there is about 1% caprolactam in the aqueous ammonium sulfate solution after Beckmann rearrangement and neu-tralization. So far, the 1% caprolactam has been extracted by benzene in an ordinary sieve-plate column with 60% recovery in Zhejiang Juhua Group Company in China, while being extracted in a pulsed packed column with 95% recovery abroad[1—3]. Because …     

The Effect of Nanoparticles on the Mass Transfer in Liquid–Liquid Extraction

This article investigates the effect of nanoparticles on mass transfer in the liquid–liquid extraction for the chemical system of n-butanol–succinic acid–water. For this purpose, nanofluids containing various concentrations of ZnO, carbon nanotubes (CNT), and TiO₂ nanoparticles in water, as base fluid, were prepared. To examine the flow mode effect on mass transfer rate, different fluid modes including dropping and jetting were employed in the process. Results show that mass transfer rate enhancement depends on the kinds and the concentration of nanoparticles and the modes of flow. It was observed that after adding nanoparticles, the mass transfer rate significantly increases up to two-fold for ZnO nanoparticles. Furthermore, the results indicate that under the circumstances in which the mass flow rate is high enough, the effect of nanoparticles on the mass transfer phenomenon is too slight.