Tri-n-octylamine Research Articles

Removal of uranium from sulfate leach liquor of salcrete deposits using tri-n-octyl amine

A uranyl sulfate leach liquor obtained by uranium leaching of a technological sample of salcrete deposits of Gabal Qatrani ore was subjected to uranium extraction using the liquid–liquid technique. Uranium was effectively extracted from sulfate leach liquor by [(10 %) tri-n-octylamine (TOA)] dissolved in xylene as a diluent. The extraction efficiency was markedly enhanced as the concentration of TOA increases from 1 to 10 %. The relevant factors controlling the extraction process of uranium using tri-n-octylamine were studied. These factors include the effect of diluents used, TOA concentration, contact time, settling time and phase ratio (O/A) v/v. The optimum extraction conditions were chosen. Stripping of uranium from the loaded TOA has been carried out using 5 % Na2CO3 as an effective stripping agent. More than 97 % of uranium was extracted by 10 % TOA, at contact time 10 min, settling time 5 min, phase ratio (VO/VA) 1/1 and at room temperature. The feasibility of using the TOA for preconcentration-separation of uranium was assessed by stripping studies. The loaded uranium onto TOA has been stripped by 100 % when using 5 % Na2CO3 as an efficient eluting agent at 15 min contact time, 5 min settling time and phase ratio (O/A) 2/1.

Process and Kinetics Study on the Acrylic Acid from Industrial Spent Acid by Complexometric Extractant

A new solvent extraction method recycling the acrylic acid (AA) from industrial waste fluid for producing acrylic acid was studied. The influencing factors of the species of diluents, concentration of extractant and temperature were investigated. The optimal process conditions were chosen that the 1-octanol as diluents, the concentration of tri-n-octylamine (TOA) 0.87mol/L, reaction temperature 298K after a series of experiments and analysis. The kinetics of extraction was studied by Lewis cell, the rate equation of extraction could be expressed as: RA=8.8×10-2[AA]1.5[TOA]2.1.

Density, viscosity and excess molar volume of binary mixtures of tri-n-octylamine + diluents (n-heptane, n-octane, n-nonane, and n-decane) at various temperatures

Densities (ρ) and viscosities (η) for binary mixtures of tri-n-octylamine (TOA)+n-heptane, TOA+n-octane, TOA+n-nonane, and TOA+n-decane are determined at T (283.15, 293.15, and 303.15)K and atmospheric pressure. The excess molar volume is calculated from the density data and is correlated by a Redlich–Kister type equation. The excess molar volume is negative for all the four systems. The results show that the volume accommodation effect is predominant in these systems. The Grunberg & Nissan equation and Fang & He equation for binary mixtures are used to correlate the experimental viscosity data. The Fang & He equation gives an average absolute deviation (AAD%) of 0.8% for TOA with alkane mixtures, better than that of 3.8% given by the Grunberg & Nissan equation.

Chromatographic separation of platinum group metals from simulated high level liquid waste using macroporous silica-based adsorbents

To separate platinum group metals (PGMs) from high level liquid waste, three novel macroporous silica-based adsorbents, namely, (Crea+Dodec)/SiO2-P, (Crea+TOA)/SiO2-P and (MOTDGA+TOA)/SiO2-P, were synthesized by introducing extractants Crea (N′,N′-di-n-hexyl-thiodiglycolamide), TOA (Tri-n-octylamine), MOTDGA (N,N′-dimethyl-N,N′-di-n-octyl-thiodiglycolamide) along with theirs modifier, Dodec (n-dodecyl alcohol), into 50μm diameter SiO2-P particles by impregnation. Chromatographic separation of PGMs from simulated high level liquid waste was investigated by column method. It was found that 100% of Pd(II) and Re(VII) could be eluted out from simulate HLLW in 3.0M HNO3 solution using three adsorbents. For Ru(III) and Rh(III), high temperature has distinct effect on the adsorption rate and a further study for Ru(III) and Rh(III) is necessary to separate them from HLLW completely. In all six column experiments, a relatively satisfactory chromatographic separation operating for PGMs from simulated HLLW was obtained using (Crea+TOA)/SiO2-P adsorbent packed column at 323K.

Recovery of Acetic Acid from the Prehydrolysis Liquor of Kraft Based Dissolving Pulp Production Process: Sodium Hydroxide Back Extraction from the Trioctylamine/Octanol System

Acetic acid is an important potential product from the prehydrolysis liquor (PHL) of the kraft based dissolving pulp production process. This study focuses on the recovery of acetic acid from an industrial PHL from an Eastern Canadian Pulp mill that contains about 1% acetic acid. Reactive extraction with tri-n-octylamine (TOA) using octanol as a diluent was investigated as the potential process. Subsequently, the complexed acetic acid in the organic phase (TOA–octanol) was back extracted using a sodium hydroxide solution, while the solvent (TOA–octanol) was regenerated. The recovered acetic acid concentration was increased with increasing organic to aqueous phase ratio but at the expense of decreased extraction efficiency. At the organic to aqueous phase ratio of 40 and the NaOH to acetic acid (HAc) mole ratio of 1, the acetic acid concentration reached to 15.0, 9.8, and 10.3% for MAA (1% model acetic acid), PHL (prehydrolysis liquor), and TPHL (treated prehydrolysis liquor), respectively. It was concluded that the reactive extraction using TOA–octanol, followed by sodium hydroxide back extraction, is an efficient process in recovering and concentrating acetic acid from PHL.

INFLUENCE OF SOLVENT POLARITY ON INTERFACIAL MECHANISM AND EFFICIENCY OF SUCCINIC ACID REACTIVE EXTRACTION WITH TRI-n-OCTYLAMINE

This article presents the results of a comparative study of reactive extraction of succinic acid with tri-n-octylamine (TOA) dissolved in solvents with different dielectric constants (dichloromethane, n-butyl acetate, and n-heptane), with and without octan-1-ol addition as phase modifier. The positive effect of octan-1-ol on extraction efficiency was quantified by means of amplification factors. For all studied systems, the addition of octan-1-ol into the solvent phase led to an increase of extraction efficiency, the most important effect being recorded for the solvent with the lowest polarity, namely n-heptane. The maximum value of amplification factor was reached for pH = 6 and indicated an increase of reactive extraction yield of about 1.26 times for dichloromethane, 1.55 times for n-butyl acetate, and 2.88 times for n-heptane.

Selective Separation of Carboxylic Acids Obtained by Succinic Acid Fermentation Using Facilitated Pertraction

Formic, acetic, and succinic acids have been selectively separated from their mixture obtained by A. succinogenes fermentation using facilitated pertraction with tri-n-octylamine (TOA). This technique allows recovering formic and acetic acids from the mixture, the feed phase raffinate containing only succinic acid. The pH-gradient between the feed and stripping phases, carrier concentration in liquid membrane, and mixing intensity of the two aqueous phases control the selectivity of acids pertraction, TOA concentration exhibiting the most important influence. At pH-value of feed phase 2, pH-value of stripping phase 10, rotation speed 500 rpm, the maximum selectivity factor (S = 133) was reached for the carrier concentration 70 g L−1.

Fractionation of Carboxylic Acids Mixture Obtained by P. acidipropionici Fermentation Using Pertraction with tri-n-Octylamine and 1-Octanol

Propionic, acetic, and succinic acids have been selectively separated from their mixture obtained by P. acidipropionici fermentation using facilitated pertraction with tri-n-octylamine (TOA). This technique allows the recovery of acetic and succinic acids from the mixture, the feed phase raffinate containing only propionic acid. The pH-gradient between the feed and stripping phases, the carrier concentration in the liquid membrane, and the addition of 1-octanol control the selectivity of acids pertraction, with TOA concentration exhibiting the most important influence. In the absence of 1-octanol, at a pH-value of feed phase = 2, pH-value of stripping phase = 10, the maximum selectivity factor (S = 25) was reached for the carrier concentration 70 g L–¹. By 1-octanol addition, at the same pH-values of the aqueous phases, the maximum selectivity factor (S = 19) was reached for lower carrier concentration, namely 50 g L–¹. The reduction of the selectivity factor for the pertraction system containing 1-octanol is compensated by diminishing the material consumption required for separation.

Fractionation of Carboxylic Acids Mixture Obtained by Succinic Fermentation using Reactive Extraction

Formic, acetic, and succinic acids have been selectively separated from their mixture obtained by A. succinogenes fermentation using reactive extraction with tri-n-octylamine (TOA) dissolved in three solvents with different polarities (n-heptane, butyl acetate, and dichloromethane) without and with 1-octanol addition. This technique allows recovering formic and acetic acids from the mixture, the raffinate containing only succinic acid. The extractant concentration and organic phase polarity control the selectivity of acids extraction. Thus, at pH = 1, the selectivity factor increased from 92, in the absence of 1-octanol; to 148, in the presence of this alcohol in organic phase. The corresponding optimum concentrations of TOA in the solvent were 30 and 50 g/l, respectively. The total separation of monocarboxylic acids from the mixture with succinic acid is possible by a multi-stage extraction process, adjusting the extractant concentration in each stage to that stoechiometrically needed for reactions with formic and acetic acids only. The addition of 1-octanol reduces the number of required extraction stages.

Rock salt vs. wurtzite phases of Co1−xMnxO: control of crystal lattice and morphology at the nanoscale

Mixed Mn–Co oxide nanoparticles have been prepared by decomposition of metal carboxylate precursors in a mixture of oleic acid (OA) and tri-n-octylamine (TOA). In addition to the stable MO rock salt structures, wurtzite-type Co1−xMnxO (0.55 < x < 0.65) nanoparticles have been synthesized for the first. Molar ratios of OA to precursor in excess of 5 were required to obtain the metastable phase. Varying the surfactant, water and precursor ratios allows control of particle size, morphology and stoichiometry: diamond cuboid, rhombohedra and hexagonal-shaped nanocrystals as well as branched rods of rock salt Co1−xMnxO (0.01 ≤ x ≤ 0.9) have also been synthesized. The rhombohedra and hexagons exhibited dimensions <50 nm on the longest axis, while nanorods had branches up to 150 nm and cuboids grew up to 250 nm on an edge. These results indicate that nanoparticle morphologies and crystal lattices arise from crystal growth and Ostwald ripening at different rates selecting for either small, smooth-surfaced wurtzite nanoparticles or large, dendritic rock salt nanoparticles. In some mixed metal Mn1−xCoxO particles, superlattice ordering is observed. As with the previously studied MnO and FeO systems, surface oxidation occurs to produce spinel phase M3O4.

숙신산 추출반응이 일어나는 단일 액적계에서의 비정상상태 물질 전달

단일 액적 시스템에서의 비정상상태 물질 전달에 대한 연구를 진행하였다. 단일 액적계를 위한 이성분계로는 옥탄올(연속상)-물(분산상) 시스템이 이용되었으며 동반되는 불균일 반응으로는 아민추출제(tri-n-octylamine,TOA)를 이용한 숙신산 추출 반응을 모델 시스템으로 선정하였다. 점도, 밀도, 용질의 분배계수, 연속상에서 하강하는 액적의 종말 속도, 용질과 추출제의 확산계수 등과 같은 시스템의 기본 특성을 파악하기 위한 실험과 이론적 계산들이 수행되었다. 액적의 종말 속도는 숙신산 농도에는 크게 영향을 받지 않는 것으로 보이나 TOA가 없을 때는 숙신산 농도에 따라 약간 증가하는 경향을 보였고, TOA 농도 증가와 함께 감소하였다. 액적의 낙하는 수직 낙하 경로를 기준으로 좌우로 진동하면서 움직이는 경향을 보였다. 낙하하는 액적에서의 물질 전달 관찰을 위해 물질 전달 셀을 제작하여 시간에 따른 액적 내의 평균 농도 변화를 관찰하였고, 그 결과를 무차원 변수를 이용하여 해석하였다. 50 g/L의 숙신산 농도 조건하에서 TOA 농도를 0.1과 0.5 mol/kg 으로 조절하였을 때, 전자의 경우에는 관찰 시간 범위 내에서 일정한 Sh 값을 유지하여 용질의 이동 방향으로의 농도 기울기가 감소함에 따라 훌럭스도 그에 비례하여 감소함을 알 수 있었지만, 후자의 경우에는 시간의 경과와 함께 Sh가 급격히 증가하는 현상을 보여 계면에서의 숙신산 훌럭스 감소에 비해 농도기울기 감소가 상대적으로 빠르게 일어남을 알 수 있다. The transient mass transfer in a single droplet system consisting of 1-octanol (continuous phase)/aqueous succinic acid solution (dispersed phase) was investigated in the presence of chemical reaction, which is acid/anion exchange reaction of succinic acid and tri-n-octylamine (TOA). This succinic acid extraction by TOA can be considered to occur at the interface between organic and aqueous phase, that is, heterogeneous reaction system. The basic properties of the system such as viscosity, density, distribution coefficient, terminal velocity of droplet, and diffusion coefficient were measured experimentally or calculated theoretically, and used for theoretical calculation of characteristic parameters of mass transfer later. The effects of succinic acid concentration on the terminal velocity was negligible in the existence of TOA, although the terminal velocity increases with succinic acid concentration in the absence of TOA. On the contrary, the terminal velocity decreases with TOA concentration. While droplets falls through organic phase, the trajectory of droplets is observed to oscillate around its vertical path. A mass trnasfer cell was prepared to monitor the mass transfer behavior in a single droplet and used to measure the mean concentration of succinic acid inside droplet. The results are expressed with dimensionless parameters. Under 50 g/L succinic acid condition, the system with 0.1 mol/kg TOA showed that the molar flux decreases in proportion to the decrease of concentration gradient, while in the case of 0.5 mol/kg TOA Sh increases rapidly with time indicating the molar flux of succinic acid decreases relatively slowly compared to the decrease in concentration gradient.

A General Phase-Transfer Protocol for Mineral Acids and Its Application in the Large-Scale Synthesis of Highly Nanoporous Iron Phosphate in Nonaqueous Solvent

As a general protocol for transferring mineral acids from an aqueous solution to an organic phase, mineral acids are extracted with secondary carbon primary amine (C9–11)2CHNH2 (commercial code: N1923) into an organic phase (e.g., heptane or benzene) because of the complexation reaction and the formation of typical reversed micelles. Based on this principle, a novel approach for a large-scale synthesis of highly nanoporous iron phosphate particles is developed via the formed RNH3+/H2PO4– (H2O)/oil reversed micelle system and ethanol–Fe3+ solutions. Synthetic conditions, such as H3PO4 concentration in reversed micelles and Fe3+ concentration in ethanol–Fe3+ solution are investigated and optimized. The product is characterized using transmission electron microscopy, Brunauer–Emett–Teller, thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. The as-obtained iron phosphate is flocculent and highly porous, exhibiting a high reported surface area of 144 m2/g. The synthetic procedure is relatively simple and is suitable for large-scale fabrication, and the used organic amines can be recycled. The power of this approach is demonstrated using other kinds of organic amines, such as tri-n-octylamine (TOA) and tri-C8–10-alkylmethyl ammonium chloride (N263), as phase-transfer reagents exhibiting promising application in the synthesis of highly nanoporous materials.

A hydrometallurgical process for the separation of aluminum, cobalt, copper and lithium in acidic sulfate media

Acid leach liquors from spent lithium-ion batteries that use lithium cobalt dioxide (LiCoO2) as a cathode active material contain valuable metals such as cobalt and lithium, as well as common metals such as aluminum and copper. The objective of this study was to develop a hydrometallurgical process that provides a degree of high selectivity between aluminum, cobalt, copper, and lithium from acidic sulfate media.The results from batch experiments showed that a selective hydroxide precipitation approach was not suitable because a significant amount of cobalt was coprecipitated with aluminum and/or copper hydroxides. In contrast, batch experiments and the subsequent data analysis indicated that the sequence of solvent extraction circuits using PC-88A, Acorga M5640, and tri-n-octylamine (TOA) extractants effectively separates four metals of interest. In the first circuit of the proposed process, copper was selectively extracted by Acorga M5640 at pH 1.5–2.0. Aluminum, cobalt, and lithium remained in the aqueous phase. In the second circuit, aluminum was selectively extracted by PC-88A at pH 2.5–3.0. For separation of the remaining cobalt and lithium, Acorga M5640 provided higher cobalt selectivity (separation factor could not be accurately obtained due to negligible lithium extraction) compared to PC-88A (βCo, 90%/Li=350 at pH 4.5) and PC-88A/TOA (βCo, 90%/Li=1,170 at pH 5.4). However, the stripping efficiency of cobalt from the Acorga M5640 organic phase was found to be low (less than 10%). Therefore, the PC-88A/TOA mixed extractant rather than Acorga M5640 is a suitable choice for the separation of cobalt and lithium.

Comparative Study on Reactive Extraction of Picolinic Acid with Six Different Extractants (Phosphoric and Aminic) in Two Different Diluents (Benzene and Decan-1-ol)

The equilibrium study on reactive extraction of picolinic acid by six different extractants (phosphoric and aminic) dissolved in two different diluents (benzene and decane-1-ol) is carried out to evaluate the performance of extractants and diluents. The extraction ability in terms of the distribution coefficient (K D) is found to be in the order of tri-n-octylamine (TOA) ≥ tri-n-dodecylamine (TDDA) > di-2-ehylhexyl phosphoric acid (D2EHPA) > tri-n-butyl phosphate (TBP) > tri-octyl methyl ammonium chloride (Aliquat 336) > tri-n-octyl phosphine oxide (TOPO) with both diluents. Decan-1-ol is found to be the better solvating medium for the acid-extractant complexes. A mathematical model based on mass action law is employed to estimate the values of partition coefficient (P) and dimerization constant (D) in physical extraction, and equilibrium extraction constants (K E) in chemical extraction. The values of loading ratios (Z) less than 0.5 imply the formation of (1:1) acid:extractant solvates in the organic phase. Decan-1-ol with TOA is the most effective solvation medium with K D, max = 9 at 0.01 kmol · m−3 of picolinic acid and K E = 19.448 m3 · kmol−1.

Recovery and separation of surfactin from pretreated Bacillus subtilis broth by reverse micellar extraction

The recovery and purification of surfactin from the fermentation broth of Bacillus subtilis ATCC (American Type Culture Collection) 21332 by extraction and stripping (back extraction) using reverse micelles was studied. Prior to extraction, the broth was precipitated by acid (HCl) at pH 4 and the precipitate was then dissolved in alkaline (NaOH) solution at pH 11. The effects of the type and concentration of surfactant, phase volume ratio, initial aqueous pH, and the presence of co-solvents on the extraction as well as the effects of the type and concentration of added inorganic salt and ethanol on the stripping were studied. It was shown that, in the absence of co-solvents, the extraction efficiency of 3.0g/L surfactin from the pretreated broth by reverse micelles of 40mM tri-n-octylamine (TOA) and 5mM Aliquat 336 in n-hexane was more than 92%. The concentrations of the added inorganic salt (ammonium sulfate and sodium chloride) in the strip solution were also optimized. The purity of recovered surfactin from the TOA reverse micelles was higher than 90% when the strip solution contained 0.43M of sodium chloride in water.

MODELING OF SELECTIVE PERTRACTION OF CARBOXYLIC ACIDS PRODUCED BY Actinobacillus succinogenes FERMENTATION

Formic and acetic acids could be selectively removed from the mixture with succinic acid by facilitated pertraction with tri-noctylamine (TOA). The pertraction selectivity is positively influenced by increasing the pH-gradient between the feed and stripping phases and carrier concentration in liquid membrane up to 70 g/L, as well as by lowering the mixing intensity of the two aqueous phases, TOA concentration exhibiting the most important influence. The cumulated influences of the considered parameters have been included in a mathematical model describing the pertraction of these carboxylic acids by means of the selectivity factor. The proposed model offers a good concordance with the experimental values of selectivity factor, the average deviation being of �5.22%.

Modeling and Optimization of Recovery Process of Glycolic Acid using Reactive Extraction

 Abstract—The equilibrium reactive extraction of glycolic acid (GA) from aqueous solution is studied using tri-n-octylamine (TOA) as extractant dissolved in organic solvents (cyclohexane and 1-decanol). Experimental studies are designed using central composite orthogonal design method to investigate the main and interaction effects of initial GA concentration in the aqueous phase (Cin, mol/L), initial TOA composition in the organic phase (CTOA,o, %v/v) and modifier composition (M, %v/v) on the degree of extraction (Y). The process design parameters are optimized based on Y and using bio-inspired optimization algorithm, called differential evolution (DE). A quadratic response surface model is satisfactorily described with R 2 of 0.98. The optimum conditions using DE are obtained as Cin = 0.24 mol/L, CTOA,o = 16.1 (%v/v), and M = 80.38 (%v/v). At this optimum conditions, a Y of 73.18% can be obtained from the model. Experimental verification gives a Y of 69.25% with a model error of 5.7%. This indicates high reliability of the model. must. Reactive extraction with an extractant (organophosphoric and aminic extractants) has been gaining great attention to solve this problem (5)-(8). In the reactive extraction, a reaction occurs between the extractant and the solute (acid) and forms an acid-extractant complex. This complex is solubilized into the organic phase using suitable extractant-diluent system, and then the acid is back-extracted from the organic phase (2). The extractant is generally diluted with an organic (conventional) solvent to get appropriate physical properties such as viscosity, density, surface tension

Recovery of acetic acid from an aqueous pyrolysis oil phase by reactive extraction using tri- n-octylamine

The application of reactive extraction to isolate organic acids, particularly acetic acid, from the aqueous stream of phase splitted pyrolysis oil using a long chain aliphatic tertiary amine is reported. Acetic acid recovery was optimized by selecting the proper amine and diluent combination and adjustment of the process conditions. The best results were obtained with tri- n-octylamine (TOA) in 2-ethyl-hexanol (40 wt%) with 84% acetic acid recovery at equilibrium conditions (room temperature). Other organic acids present in the feed (formic acid and glycolic acid) were also co-extracted (92% and 69% extraction efficiencies), as well as relatively non-polar compounds like substituted phenolics and ketones. The continuous reactive extraction process was successfully demonstrated in a centrifugal contactor separator (CCS) device, and acetic acid recoveries of 51% and 71% were obtained in a single CCS device and a two stage cross currently operated cascade, respectively.

Influence of Solvent Polarity on the Mechanism and Efficiency of Formic Acid Reactive Extraction with Tri‐n‐Octylamine from Aqueous Solutions

AbstractThe reactive extractions of formic acid with tri‐n‐octylamine (TOA) dissolved in three solvents with different dielectric constants (dichloromethane, butyl acetate, n‐heptane) without and with 1‐octanol as phase modifier were comparatively analyzed. The results indicated that the mechanism of the interfacial reaction between acid and extractant (Q) is controlled by the organic phase polarity. In the absence of 1‐octanol, the structures of the extracted complexes are (HA)2Q2 for dichloromethane and butyl acetate, and (HA)2Q4 for n‐heptane. These structures are modified by adding 1‐octanol and become (HA)2Q for extraction in dichloromethane or butyl acetate, and (HA)2Q2 for extraction in n‐heptane. Although the presence of 1‐octanol improves the extraction efficiency, it leads to a reduction of the extraction constants for all considered solvents, an influence that is more significant for n‐heptane.

Influence of Organic Phase Polarity on Interfacial Mechanism and Efficiency of Reactive Extraction of Acetic Acid with Tri-n-octylamine

The reactive extractions of acetic acid, HAc, with tri-n-octylamine (TOA), Q, dissolved in three solvents with different dielectric constants (dichloromethane, butyl acetate, and n-heptane) without and with 1-octanol as phase modifier have been comparatively analyzed. The results indicated that the mechanism of the interfacial reaction between acid and extractant is controlled by the organic phase polarity. In absence of 1-octanol, the structures of the extracted complexes are HAc.Q for dichloromethane, HAc.Q2 for butyl acetate, and (HAc)2Q4 for n-heptane. These structures are modified by adding 1-octanol and become HAc.Q for extraction in dichloromethane or butyl acetate and (HAc)2Q2 for extraction in n-heptane, respectively. Although the presence of 1-octanol improves the extraction efficiency, it leads to the reduction of extraction constants for lower-polar solvents, influence that is more significant for n-heptane.