Tri-n-octylamine Concentration Research Articles

Selective and efficient separation of levulinic, acetic and formic acids from multi-acid solutions by adjusting process parameters

This investigation focuses on the recovery of levulinic- (LA), acetic- (AA) and formic acids (FA) from aqueous mixed-acid solutions by reactive extraction using tri-n-octylamine (TOA). Alcohols were found to be the most efficient solvents tested. Recoveries increased with shorter alcohol chain length and higher TOA concentrations. Yields decreased with pH and maximum efficiencies were obtained at the unadjusted pH (1.83) of the ternary-acid solutions for all acids; with LA, maximum selectivity occurred at pH 5. Higher TOA levels enhanced efficiency in mixtures but slightly reduced selectivity. For LA recovery, efficiency and selectivity using 0.5 M TOA in 1-hexanol were 92 % and 23.8 %, respectively. Co-extraction of AA ceased at consecutive extractions (from 2nd to 10th) and 93.6 % of LA was recovered with a selectivity of 98 % after ten subsequent steps. LA in the organic phase was stripped with an efficiency of ~91 % with aqueous 1.0 M NaNO3. Selective extraction of AA and FA from binary-acid solutions was achieved at pH 5. The selectivity and separation factor decreased at higher TOA concentrations; however, 94.2 % of the AA was recovered with a selectivity of 93 % after seven successive extractions, followed by ~93 % recovery by back extraction. The remaining FA (94.2 %) in the aqueous solution had a selectivity of ~95 %. The data show that multi-stage reactive extraction can selectively separate LA, AA and FA from ternary- and binary-acid solutions.

Elimination of glufosinate ammonium from aqueous solution with hollow fiber supported liquid membrane and mathematical modeling

A hollow fiber supported liquid membrane (HFSLM) was used to extract and eliminate glufosinate ammonium from aqueous solution using TOA (tri-n-octylamine) in hexane and sodium hydroxide (NaOH) as carrier and stripping phase, respectively. Maximum extraction (∼76%) and stripping (∼75%) were achieved by feed solution at pH 1.0, temperature 60 °C, TOA concentration 6% (v/v) and NaOH concentration 1.0 M. The developed mathematical model exhibited high precision when predicting the concentration of glufosinate ammonium in raffinate solution and extraction percentage under different feed flow rates, with correlation coefficient (R 2) 0.9863.

Investigation of reactive extraction of monocarboxylic acids with menthol-based hydrophobic deep eutectic solvent by response surface methodology

ABSTRACT The growing demand for producing organic acids by fermentative techniques has increased the significance of separating carboxylic acids from their fermentation broth with the reactive extraction process. Considering the environmental impacts, deep eutectic solvents can be considered as a potential green alternative for the replacement of volatile organic solvents commonly used in the extraction process. In this study, a new type of green solvent named hydrophobic deep eutectic solvent (HDES) based on decanoic acid as a hydrogen bond acceptor and menthol as a hydrogen bond donor was utilized for the reactive extraction of formic, acetic, and propionic acids from their aqueous solutions. The effect of initial acid concentration, HDES molar ratio, and tri-n-octyl amine (TOA) concentration on extraction efficiency was investigated. Modeling of the reactive extraction process was performed via a response surface methodology with a central composite design. Herein, the effect of the parameters of TOA concentration, HDES molar ratio, and initial acid concentration on the distribution coefficient was investigated. According to the results, it was reported that the most effective parameter on the extraction efficiency (%E) was the amount of extractant. The results of the experimental studies showed that the highest separation efficiency was obtained for 5% initial concentrations of formic, acetic, and propionic acids by using a mixture of 0.5 HDES molar ratio solvent and 1.9 mol/L TOA. The extraction efficiencies of these acids were found to be 88.71, 92.52, and 95.90 with ±0.1 standard deviation, respectively.

Liquid-liquid extraction of zirconium(IV) from sulphuric acid medium using a binary mixture of tri-n-octylamine and Cyanex923 in kerosene

The extraction behaviour of zirconium(IV) from sulfuric acid medium has been studied with a binary mixture of tri-n-octyl amine (TOA) and Cyanex923 (a mixture of four trialkyl phosphine oxides) in kerosene using a novel liquid-liquid extraction method. Quantitative extraction of zirconium(IV) with binary mixture of Cyanex923 and TOA in kerosene was studied by changing different parameters such as acid variation, extractant variation, effect of chloride ion concentration, effect of temperature, metal concentration variation, diluent effect, and pH effect. The percentage of extraction of zirconium(IV) decreased when the concentration of Cyanex923 and TOA increased. The percentage of zirconium(IV) was observed as 97.56% in a binary mixture of 0.007 M Cyanex923 and 0.06 M TOA. Kerosene was found to be an effective diluent for the extraction of zirconium(IV) with 97.56% extraction using a binary mixture of Cyanex923 and TOA. In addition, the stripping of the zirconium(IV) metal ion in the organic phase was also examined.

Reactive separation of nicotinic acid from aqueous solution using tri-n-octylamine in biocompatible modifier diluent mixture: Influencing parameters exploration, mechanism insights, thermodynamics, regeneration of solvents and column design

In the current study, reactive extraction using tri-n-octylamine (TOA) with n-dodecane and lauryl alcohol (modifier) as biocompatible extraction system is investigated for intensification of recovery of nicotinic acid (NA), a pharmaceutical industrially important compound. The effect of important parameters such as initial NA concentration (0.014 - 0.083 mol.kg−1), TOA concentration (0.148–1.201 mol.kg−1), initial pH value (2.5–6) and temperature (298–328±1 K) are explored and optimized as NA concentration of 0.548 mol.kg−1, TOA concentration (0.706 mol.kg−1 or 20% w/w), pH (3.3) and Temp.298±1 K at 101.325±1 kPa for 92% of extraction degree. Equilibrium mechanism insights are determined as stoichiometry of reactions, overall equilibrium constant (KE) and individual equilibrium constant (K11 and K21) for 1:1 and 2:1 NA-TOA complexes. Theoretical reaction mechanisms are also supported by FT-IR data analysis. Evaluations of entropy (∆S0), enthalpy (∆H0) and Gibb's free energy (ΔG0) are carried out to find suitability of the process. A suitable column (RDC) design at optimized conditions is proposed and theoretical stages (NTS) are calculated which are found to be 5. Finally, solvent regeneration as 99% is achieved using 0.05 M NaOH solutions. This study is useful to intensify the process and design an economical industrial scale recovery of NA from dilute aqueous/fermentation broth.

Experimental and Theoretical Equilibrium Insights in the Reactive Extraction of Pimelic Acid with Tri-n-octylamine in Natural Solvents

The theoretical and experimental studies on the reactive extraction of pimelic acid (PA) from dilute aqueous solutions with tri-n-octylamine (TOA) in three different green and natural solvents namely, rice bran oil, sunflower oil (SFO), and soybean oil are carried out. In addition, physical extraction (extraction with pure solvent, natural oil) is also studied to determine the partition and dimerization constants. The experiments on reaction equilibria were performed to calculate the extraction efficiencies with variable TOA concentration, PA concentration, type of diluent/solvent, and temperature at atmospheric pressure (101.325 ± 1 kPa). The acid distribution coefficient (KD), degree of extraction (E, %), and loading factor (Z) were calculated as the extraction efficiencies to recover the PA from aqueous solution. The maximum KD (7.76) and extraction yield (88.58%) were obtained for initial PA concentration (CH2P,o= 0.2497 kmol·m–3) with 0.687 kmol·m–3 TOA concentration (C̅S,o) dissolved in sunflower oil. The overall stoichiometry and reaction equilibrium constant (KE) and individual acid-extractant complexation constants (K11, K12, K21, and K31) of 1:1, 1:2, 2:1, and 3:1 PA–TOA complexes in the organic phase and their complex concentrations (C11, C12, C21, and C31) are determined using an equilibrium chemical model and bioinspired genetic algorithm, differential evolution, for better understanding of the reaction mechanism. Moreover, based on extraction conditions, the thermodynamic study is carried out to determine the change in enthalpy (−1320.11 J·mol–1), entropy (−3.63427 J·mol–1·K–1), and Gibbs free energy (−254.72 J·mol–1·K–1) of reactive separation of PA with TOA–SFO.

Kinetics study on reactive extraction of formic acid using tri-n-octyl amine diluted in n-butyl acetate

Abstract Formic acid is the simplest yet commercially valuable organic acid. It is widely used as a stabilizer and sterile agent in food industries. Reactive extraction is highly effective and selective technique for the recovery of formic acid from dilute solutions. Kinetics study provide rate controlling step (reaction rate or diffusion) that is required to visualize the intrinsic reactive extraction mechanism. Kinetics study of formic acid (0.1–0.4 kmol/m3) extraction with tri-n-octyl amine (TOA) (0.11–0.67 kmol/m3) in n-butyl acetate (NBA) was investigated at temperature 308 ± 1 K. Kinetics study was carried out in a Lewis cell. Effect of formic acid concentration, TOA concentration, speed of stirring, and phase volume ratio were investigated to find the reaction regime. Diffusivity coefficient (DA) of formic acid in NBA was found 3.20 × 10−7 m2/s. Reaction rate constant was evaluated to be 0.616 m3/mol s. The physical mass transfer coefficient (kL) was evaluated to be 0.8278 × 10−6 × N 3.387. The reaction was independent on hydrodynamic parameters and falls under fast reaction regime. The reaction was found first order with respect to both formic acid as well as TOA, occurring in the diffusion film. The findings of the present work are helpful in the selection of commercially viable extraction system and in the design of extractors.

Effect of temperature on equilibria for physical and reactive extraction of protocatechuic acid

Owing to its biological and chemical applications, the separation of protocatechuic acid, a polyphenol compound, is of interest to researchers. Extraction studies with initial acid concentration (0.001–0.01 kmol m−3) using aminic extractant tri-n-octyl amine (TOA) (0.2287 kmol m−3 -1.1436 kmol m−3) in diluent octanol at diverse temperature ranges from 288 K - 313 K was done. Parameters like loading ratio, distribution coefficient, equilibrium complexation constant, diffusion coefficient, number of stages necessary for protocatechuic acid counter-current extraction were obtained; this information is useful in designing a process for the in situ separation of the acid from the fermentation broth as well as from the waste streams. The increase in temperature distribution coefficient was found to increase up to the temperature of 303 K and was found to decrease with a further rise in temperature. The entropy and enthalpy values for the reaction at different temperatures were obtained. The highest extraction of 91.1 % and distribution coefficient of 1.14 were obtained at 313 K for an acid concentration of 0.01 kmol m−3, and TOA concentration of 1.1436 kmol m−3 and 4 stages are required for counter-current extraction process for acquiring the required separation efficiency. Development of 1:1 complex of protocatechuic acid and TOA take place as concluded from the values of the loading ratio.

Reactive Extraction of Levulinic Acid using Tri-n-octylamine in 1-Octanol: Equilibria and Effect of pH

Reactive extraction is a sophisticated separation technique used for the recovery of carboxylic acids from fermentation broth. Levulinic acid is a versatile chemical. A right combination of extractant and diluent will provide a high yield. The reactive extraction of levulinic acid from aqueous solution with tri-n-octylamine (TOA) dissolved in 1-octanol was investigated at room temperature. The effect of pH was studied. From the physical and chemical equilibrium experimental results, the distribution coefficient (KD), extraction efficiency (E%), loading ratio (Z), stoichiometric loading factor (ZS) and modified separation factor (Sf) are calculated. It was found that physical extraction provided less yield compared to chemical extraction. A maximum KD was obtained as 5.248 using 40% TOA (0.9059 mol/L) while 83.99 % of the levulinic acid was extracted. By increasing the initial concentration of levulinic acid increased the concentration of levulinic acid in both the organic phase and aqueous phase. As the concentration of TOA increases from 10 to 40 % (0.2264 mol/L to 0.9059 mol/L), the distribution coefficient and extraction efficiency also increase. By increasing the pH from 3 to 7, the distribution coefficient and extraction efficiency were drastically affected.

Tri-n-octylamine impregnated Seplite LX-16 resin for extraction of U(VI) from sulfate medium

Impregnation of tri-n-octylamine (TOA) into Siplite LX-16 resin, by two commonly used methods namely; wet and dry impregnation method, was studied and applied for uranium extraction from sulfate medium. The resin beads were characterized using FT-IR and FE-SEM analysis. The influence of different parameters such as effect of TOA concentration, pH, aqueous sample and eluant flow rates were investigated. Maximum sorption of U(VI) was obtained using 30% TOA/Siplite LX-16 prepared by the dry method at a pH range of 1.4–1.6. Flow rate of 1.0 mL/min for the pregnant sample was favorable for quantitative sorption of uranium during the extraction step while the flow rate of 0.5 mL/min for eluant solution was effective for the elution step. TOA-impregnated Siplite LX-16 resin has been properly prepared and applied for U(VI) extraction from sulfuric acid medium.

Reactive extraction of levulinic acid using tri-n-octylamine in 1-hexanol

Reactive extraction of levulinic acid using trin- octylamine (TOA) in 1-hexanol was investigated by physical and chemical extractions from aqueous solution at room temperature. Using the equilibrium data, the distribution coefficient (KD), extraction efficiency (E%), loading ratio (Z), stoichiometric loading factor (ZS) and modified separation factor (Sf) are evaluated. It was observed that chemical extraction provided a better yield than physical extraction. A maximum KD was obtained as 10.715 using 40% TOA (0.9059 mol/L) while 91.46% of the levulinic acid was extracted. By increasing the initial concentration of levulinic acid resulted in a decrease of KD and E%. The KD and E% increased by increasing the TOA concentration from 10 to 40% (0.2264 mol/L to 0.9059 mol/L).

Reactive extraction of gallic acid from aqueous solution with Tri-n-octylamine in oleyl alcohol: Equilibrium, Thermodynamics and optimization using RSM-rCCD

Concern of the recovery of important constituents found in nature, industrial waste streams and fermentation broth, the present study is aimed to recover gallic acid (HGA) from aqueous solution using tri-n-octylamine (TOA) in a non-toxic diluent, oleyl alcohol (OA). The optimal conditions for maximum extraction of HGA (90.1%) are determined as (i) initial concentration of HGA (CHGA,o) = 0.0588 mol/L, (ii) initial TOA concentration (C¯TOA,o) = 0.2762 mol/L, (iii) pH = 2.0 and (iv) temperature (T) = 25.0 °C, at atmospheric pressure (101.325 kPa), using response surface methodology (RSM) with rotatable central composite design (rCCD). The statistical analysis with ANOVA is used to model fitness and shows a high coefficient of determination (R2 = 97%). At optimum conditions, the insights of reactive extraction are determined using differential evolution (DE) approach, a bio-inspired algorithm. The apparent stoichiometric coefficient (number moles of acid per mole of extractant, m = 1.28) of reactive extraction, overall equilibrium constant (KE = 85.77) and individual equilibrium constants (K11 = 110.32 and K21 = 1106.77) are calculated. Thermodynamic study at four different temperatures (20, 30, 40 and 50 °C) is also carried out to determine enthalpy (ΔH = −12.97 J/mol), entropy (ΔS = −3.77 J/mol·K) and Gibb’s energy change (ΔG = −12370.44 to −5399.96 J/mol·K) of reactive extraction.

Separation of Protocatechuic Acid Using Tri-n-Octylamine: Experimental and Mathematical Investigation

Protocatechuic acid has wide pharmacological significance. The separation of protocatechuic acid (0.001–0.01 mol·kg–1) from tri-n-octylamine (TOA) (0.3140–2.827 mol·kg–1), in petroleum ether, toluene, and isobutyl acetate was investigated at 298 ± 1 K as well as atmospheric pressure. The equilibrium complexation constant (KE), extraction efficiency (E), distribution coefficients (KD) as well as loading ratio (Z) are used to explain the magnitude of protocatechuic acid loading in the organic phase. The best diluent was isobutyl acetate having a maximum distribution value as 4.57 and efficiency of 82.06% for 0.01 mol·kg–1 protocatechuic acid and 2.827 mol·kg–1 TOA concentration. For the various diluents in TOA, considering KD and %E the extraction capability was observed in the order isobutyl acetate (82.06%) > toluene (61.21%) > petroleum ether (58.88%). The design parameters for the extraction process, minimum ratio of solvent to feed (S/Fmin), and theoretical stages required were calculated. The Langmuir...

Liquid-liquid extraction of Zr(IV) from sulphuric acid medium using tri-n-octyl amine in kerosene

The extraction behavior of Zr(IV) with tri-n-octyl amine (TOA) in kerosene was studied through a new method of solvent extraction. The mechanism of extraction and the species extracted were identified. Quantitative extraction of Zr(IV) with TOA in kerosene was studied by changing different parameters such as acid variation, diluent effect, metal concentration variation, extractant variation, effect of salting out reagent concentration and effect of temperature. It was observed that the percentage of extraction of Zr(IV) increased when the concentration of TOA and the percentage of extraction also increased when the metal ion concentration increased. The percentage of Zr(IV) became 97.4% with 0.1 M TOA from 3.0 M sulphuric acid. Kerosene was found to be effective diluent for the extraction of Zr(IV) with TOA.

Modeling and Optimization of Reactive Extraction of Isonicotinic Acid Using Tri-n-octylamine in Biocompatible Diluents Mixture: Response Surface Methodology and Regeneration of Solvents

The present study is aimed to recover the pharmaceutically and biochemically important compound, isonicotinic acid (iNA) from aqueous/fermentation broth in a biocompatible extraction system using an intensified approach, reactive extraction. Tri-n-octylamine (TOA) is used as extractant in nontoxic diluent mixtures of dodecane and n-decanol (modifier) in 1:1 v/v. However, modeling and optimization of reactive extraction using three process parameters, that is, initial iNA concentration in aqueous solution (0.0032–0.0368 kmol·m–3), TOA concentration in organic phase (0.110–1.259 kmol·m–3) and initial pH values of aqueous phase (1.32–4.68) is performed using response surface methodology (RSM), and the rotatable central composite design (rCCD) matrix is used in the experimental design. The RSM model suggests that initial acid concentration is the most influential factor, whereas pH value change shows antagonistic impact on %E. At equilibrium, under constraint condition (lowest TOA concentration selected) that...

Reactive separation of protocatechuic acid using Tri-n-octyl amine and Di-(2-ethylhexyl) phosphoric acid in Methyl isobutyl ketone

Abstract Protocatechuic acid is used extensively in pharmacological and related industries which can also be obtained by fermentation. Reactive separation by means of reactive extractant is a favourable alternative to recover carboxylic acids from the aqueous dilute streams and the fermentation broth. In this paper, the reactive separation of protocatechuic acid were performed by D2EHPA (Di-(2-ethylhexyl) phosphoric acid) and TOA (tri-n-octyl amine) dissolved in MIBK (Methyl isobutyl ketone) at 298 K. Distribution coefficients, degree of extraction, complexation constants and loading ratio were estimated. The equilibrium for protocatechuic acid-extractant-diluent system was represented using Langmuir model, mass action law and relative basicity model. Results obtained from model were found to be close to experimental data. TOA was found more effective than D2EHPA for the recovery of protocatechuic acid having 5.39 as maximum distribution coefficient and 84.36% efficiency at 0.01 mol L−1 and 1.1437 mol L−1 concentration of protocatechuic acid and TOA respectively.

Recovery of levulinic acid by reactive extraction using tri-n-octylamine in methyl isobutyl ketone: Equilibrium and thermodynamic studies and optimization using Taguchi multivariate approach

Abstract Recovery of levulinic acid from an aqueous solution using a tertiary amine, tri-n-octylamine (TOA), as an extractant in methyl isobutyl ketone (MIBK) was studied at different temperatures (293–333 K). The physical equilibrium studies were performed using MIBK as a diluent. Partition ( P ) and dimerization ( D ) coefficients were found to decrease noticeably with increasing temperature. The coefficient of distribution was found to be very low in physical equilibrium. Chemical equilibrium studies were conducted using various concentrations of the extractant. The highest coefficient of distribution ( K D ) and efficiency of extraction ( % E ) were found to be 58.0 and 98.0% respectively for 0.1 kmol m−3 of levulinic acid and 0.678 kmol m−3 of TOA at 293 K. Chemical equilibrium studies showed the formation of 2:1 complex as the main mechanism in the reactive extraction. Taguchi mixed design multivariate approach ( L 18 ) was used to optimize the process variables. S/N ratio (larger-is-better) criterion was adopted to maximize the performance parameters. The optimum combination of variables was found to include acid concentration ( X 1 ) = 0.3 kmol m−3, TOA concentration ( X 2 ) = 0.678 kmol m−3 and temperature ( X 3 ) = 293 K. A confirmation run was conducted using these parameters and K D and % E values from this run were determined to be 11.83 and of 92.2%, respectively, which were very close to the predicted values of K D = 12.78 and % E = 94%.

Modeling and Optimization of Reactive Extraction of Gallic Acid Using RSM

Reactive extraction was experimentally investigated for recovery of gallic acid (GA) from the aqueous solution using tri-n-octylamine (TOA) as extractant in hexanol. All experiments were carried out according to statistical design in order to develop a regression model used to optimize the extraction of GA. Two independent variables were selected as: initial concentration of GA (CGA0) in aqueous phase and concentration of TOA (CTOA) in organic phase. The statistical analysis showed that both the independent variables had significant effect on response value, followed by the quadratic and interactive effect on response. A five-level central composite rotatable design (CCRD) was employed. Analysis of variance (ANOVA) showed a high coefficient of determination (R2 = 99.0%). The optimal extraction conditions of GA were determined as: CGA0 = 2.01 g/L, CTOA = 6.8% v/v. At the optimum conditions, the experimental yield of GA was 91.9%, which was in close agreement with the predicted value of 93.2%.

Electrodeposition of Cobalt and Lead in the Hybrid Liquid Membrane - Electrodialysis-Electrolysis Process

A novel method for Co (II) and Pb (II) recovery from acidic solutions is presented. The extraction of Co (II) and Pb (II) ions using the bulk liquid membranes during a galvanostatic electrodialysis process accompanied by cathodic electrodeposition of the metals was studied. Solutions of di (2-ethylhexyl) phosphoric acid (D2EHPA) with admixtures of tri-n-octylamine (TOA) in 1,2-dichloroethane were used as the liquid membranes. Effects of current density, Co (II) and Pb (II) concentrations in the feed solution, sulfuric or nitric acid concentration in the feed solution, D2EHPA and TOA concentration in the liquid membrane, of the type and concentration of acid in the cathodic solution were studied, and optimal conditions were determined. It is demonstrated that a practically complete (98-99%) removal of Co (II) and Pb (II) from the feed solutions containing 0.01 mol∙L-1 CoSO4 or 0.01 mol∙L-1 Pb (NO3)2 is achieved during 1.0 − 4.0 h of electrodialysis. A possibility of effective transfer of Pb (II) into dilute solutions of perchloric and nitric acids was demonstrated. The liquid membranes ensure the recovery of Co (II) ions into dilute solutions of perchloric, sulphuric, hydrochloric and nitric acids. Adherent, compact cobalt and lead electrodeposits with a fine-grained structure were obtained in the studied systems.

The kinetic analysis of optimization and selective transportation of Cu(II) ions with TNOA as carrier by MDLM system

This study covers the transportation of Cu(II) ions by multi-dropped liquid membrane (MDLM) system and tri-n-octylamine (TNOA) as carrier in kerosene. Batch experiments are held to obtain optimum conditions for the transportation of Cu(II) ions such as volume of donor, organic, and acceptor phase 100ml, pH of donor phase 9.00, temperature 298.15K, concentration of H2SO4 in acceptor phase 1.00mol·L−1, concentration of TNOA in organic phase 5.00×10−3mol·L−1 and rate of peristaltic pump 50ml·min−1. Optimum circumstances of this extraction are as follows: pH of donor phase is 9.00, concentration of TNOA is 5.00×10−3mol·L−1, 1.00mol·L−1 H2SO4 as acceptor phase, and flux rate is 50ml·min−1. Cu(II) ion transportation is consecutive first order irreversible reaction. Activation energy is found as 5.22kcal·mol−1 (21.82kJ·mol−1), this process is called as diffusion controlled system. Selective transportation of Cu(II) ions with alkaline, alkaline earth, and different heavy metal ions at optimum conditions of single Cu(II) extraction was conducted. According to the selective transportation Cu(II) ions with alkaline and alkaline earth metal ions, Na+, K+, and Ba2+ ions are not detected in the acceptor phase, but 12.00% of Ca2+ ions is transported from donor phase to acceptor phase. At the end of the simultaneous extraction of Zn(II), Fe(III), and Mo(VI) with Cu(II) ions, 2.20% of Mo(VI), 0.80% of Fe(III) and 3.60% of Zn(II) are detected in the acceptor phase.