Trioctylamine Concentration Research Articles

Reactive separation of gallic acid using trioctylamine in oleyl alcohol and dodecane mixtures: Equilibrium insights, modeling and optimization using RSM and ANN approaches

ABSTRACT The aim of present study is to model and optimize gallic acid (GA) reactive extraction from aqueous solution with trioctylamine (TOA) dissolved in the biocompatible mixture of oleyl alcohol, a modifier and dodecane, an inert diluent using a statistical modeling approach, response surface methodology (RSM) with rotatable central composite design, and artificial neural network (ANN). The optimal values of input parameters for maximum extraction (86%) of GA are found as follows: (i) initial GA concentration ( = 0.387 mol/L); (ii) temperature, T = 26.5°C; (iii) initial TOA concentration ( = 0.049 mol/L); (iv) modifier volume, V = 70% at 101.325 kPa pressure. Predicted responses in terms of extraction degree using RSM and ANN are found to be very close to experimental values. The overall apparent equilibrium constants (K E = 37.24 and 22.38) and stoichiometry of reaction between acid and extractant (m =1.25 and 1.16) are determined considering negligible and 50% physical extraction, respectively. Individual equilibrium constants ( and ) for 1:1 and 2:1 GA:TOA complexes and their concentrations, C11 and C21, respectively, are calculated. Differential evolution approach, a bio-inspired algorithm, is used to investigate the insights of extraction mechanism at the optimum conditions.

Optimization and experimental design by response surface method for reactive extraction of glutaric acid

Abstract Glutaric acid is an attractive chemical compound which can be used for the manufacturing of polyesters, polyamides, and polyols. It can be produced by the synthesis (chemical method) and fermentation (biological method) process. Glutaric acid is presented with the lowest quantity in the fermentation broth and industrial waste streams. The separation methods of glutaric acid are difficult, costly, and non-environment friendly from fermentation broth. Reactive separation is a simple, cheapest, and environment-friendly process for the recovery of carboxylic acid. Which can be employed for the separation of glutaric acid with lower cost and environment-friendly process. In this study, response surface methodology (RSM) was used as a mathematical technique to optimize and experimental design for investigation of the reactive separation of glutaric acid from the aqueous phase. As per RSM study, 20 experiments with different independent variables such as concentration of glutaric acid, % v/v of trioctylamine, and pH for recovery of glutaric acid were performed. The optimum condition with maximum efficiency (η) 92.03% for 20% trioctylamine and pH = 3 at 0.08 mol/L of glutaric acid initial concentration were observed. The lower concentration of trioctylamine provides sufficient extraction efficiency of glutaric acid. This method can also be used for the separation from fermentation broth because a lower concentration of trioctylamine which makes this process environment-friendly. The optimization condition-defined quadratic response surface model is significant with R 2 of 0.9873. The independent variables defined the effect on the extraction efficiency of glutaric acid. This data can be used for the separation of glutaric acid from industries waste and fermentation broth.

Butyric Acid Reactive Extraction Using Trioctylamine in 1-Decanol: Response Surface Methodology Parametric Optimization Technique

The optimization of the reactive extraction of butyric acid from an aqueous stream was effectively carried out using response surface methodology. Three process parameters were studied, viz. initial butyric acid concentration, trioctylamine concentration and temperature, to examine the interactive effects on extraction efficiency and distribution coefficient. A Box-Behnken design comprising of seventeen experimental runs was utilized in the reactive extraction study of butyric acid. Analysis of a second-order polynomial model yielded the following optimal conditions: temperature 301.829 K, initial butyric acid concentration 0.493 kmol/m3, trioctylamine composition 26.417%v/v with the following responses: distribution coefficient = 28.795 and extraction efficiency of 96.666%. Experimental validation of the model was carried out with the predicted process variables, and the responses obtained (distribution coefficient = 27.171, extraction efficiency = 96.450%) were in close conformity to the predicted outcomes. Three-dimensional surface plots obtained from statistical analysis demonstrated that the butyric acid concentration and TOA composition had a more significant and interactive effect than the temperature on the response value in the reactive extraction process.

Process development for the separation of niobium and tantalum from fluoride medium using trioctyl amine and application of Taguchi's method to optimize solvent extraction parameters

Niobium and tantalum have a wide range of application in various industries such as steel and electronic industry. The conventional tributyl phosphate based solvent extraction process for producing pure niobium and tantalum generates solid waste which is a mixture of fluoride with other anions like sulphate, chloride and acetate. This waste has no industrial application and requires effective disposal. The aim of this study is to develop a trioctyl amine (TOA) based solvent extraction process, which eliminates the generation of mixed fluoride waste. Batch experiments were carried out to determine the suitable extraction conditions and effective stripping agents. The developed process involves single stage co-extraction of niobium and tantalum followed by selective stripping of pure niobium. The tantalum rich organic phase is then stripped to obtain pure tantalum. The process parameters were optimized (for obtaining the highest purity of niobium) using Taguchi's method and the significance of each parameter was determined using Analysis of Variance (ANOVA). The optimum organic to aqueous phase volume (O/A) ratio for extraction is 2, TOA concentration in the organic phase is 25% (v/v), and the O/A ratio for stripping is 3. The most important parameter in determining the purity of niobium in the strip solution is TOA concentration in the organic phase (contribution 49.85%), followed by O/A ratio of stripping (contribution 47.20%). The developed process resulted in 98.88% pure niobium and tantalum of 98.08% purity.

Extraction of 1-amino-2-Naphthol-4-Sulfonic acid from wastewater using trioctylamine (N, N-dioctyloctan-1-amine) in methyl isobutyl ketone

Wastewater containing 1-amino-2-naphthol-4-sulfonic acid (ANS) is mainly derived from the dye production process, causing serious environmental problems. In this work, extraction of ANS from wastewater was carried out using trioctylamine (TOA) under condition of methyl isobutyl ketone (MIBK) as a diluent. The effects of diluent type, concentration of TOA, temperature and pH on the distribution coefficient (D) were discussed in detail. The results showed that the value of D = 76 was obtained with TOA (1.41 mol kg−1) + MIBK at 25 °C and pH = 1.1. After that, the extraction mechanism was determined by analyzing the chemical bonds of the complex compound using UV–vis, FT-IR and 1H NMR. The experimental results showed that the extractant could be regenerated by back extraction. Specially the distillation process was simulated using Aspen Plus and the results verified its feasibility in the process of extractant regeneration. The proposed extraction system is conductive to both environment and technology.

Selection of Liquid Membrane Component for Lignosulfonate Removal from Liquid Waste Solution using Emulsion Liquid Membrane Process

Removal of lignosulfonate from pulping process as an external biofuel and in specialty chemicals is growing such as in production of vanillin, animal feed pellets binder, pesticides, ect. Though lignosulfonate(LS) is nontoxic, it imparts brownish black colour to the water bodies and makes them unsuitable for usage in other processes. Therefore the removal and recovery of LS is needed. This study examined the liquid membrane component selection of lignosulfonate(LS) removal from liquid waste solution using trioctylamine (TOA) as a mobile carrier in batch process using mixer settler. Several parameters have been investigated such as choice of diluents, effect of pH, concentration of carrier, concentration of LS solution, organic to aqueous treat ratio, choice of stripping agent and concentration of stripping agent. The results show that at favorable condition of 0.1M concentration of TOA in kerosene, pH 3 of solution, treat ratio 1:15 and 0.7 M NaOH solution as stripping agent showed that almost 90 percent of lignin was extracted and recovered in receiving phase.

Permeation and modeling studies on Ge(IV) facilitated transport using trioctylamine through supported liquid membrane

Germanium transport from a solution containing tartaric acid by a flat sheet supported liquid membrane (FSSLM) using trioctylamine (TOA) as a carrier and polytetrafluoroethylene (PTFE) as a membrane was investigated. A mass transfer model was developed to monitor the transport process based on experimental results. The effect of parameters such as feed solution pH, TOA concentration, initial germanium concentration, and strip hydrochloric acid concentration on the germanium flux and the transport percentage were studied. A high permeation was observed at a feed solution pH of 3.00, 40%v/v TOA and 5 mg/dm3 Ge4+. At HCl concentrations of 1–3 mol/dm3, the germanium transport was complete. Finally, based on the mass transfer model, the aqueous and organic resistance values were 11,802 and 860.85 h/cm, respectively. The validity of the model was investigated by fitting the model and experimental data. The correlation coefficient of 0.99 showed the validity of the model.

Selective recovery of pyruvic acid from two and three acid aqueous solutions by reactive extraction

Abstract In this study, a multi-stage reactive extraction system is devised for the selective recovery of pyruvic acid (PA) from a multiple-acid solution having a carboxylic acid composition identical to that obtained in microbial fermentation. With single-stage extraction, approximately 40% of the acetic acid (AA) is preferentially and selectively recovered from the aqueous three-acid solution using 0.1 M trioctylamine (TOA) in 1-octanol. Pyruvic acid is the only solute positively affected by an increase in the TOA concentration; however, the purity of the final extract is compromised by co-extracted acids. The distribution coefficient (KD) values obtained in three-acid solutions are lower than those obtained in single-acid solutions, showing the antagonistic effects due to the presence of other acids. However, in two-acid solutions, the presence of lactic acid (LA) at an initial concentration of about 7–20% (0.05–0.15 M) of that of PA (0.75–0.85 M) causes an increase of 33–80% on the KD of the latter. Using 0.6 M TOA in 1-octanol, 92% of initial PA is recovered from the two-acid solution. The competition with the other acid(s) for ion pair formation and its marked hydrophilicity hinders the extraction of LA from multiple acid solutions. Thus, a successful selective separation is achieved for the three acids present in the aqueous phase. A further increase in the initial concentration ratio of LA to PA in two-acid solution results in reduced KD values for the latter. The maximum separation factor of 54.3 is obtained at the lowest acid ratio (AR, 0.19) and highest TOA concentration (0.6 M). Hence, reactive extraction can be successfully employed to selectively recover PA from two and three-acid aqueous solutions.

Recovery of methyl orange and Congo red from aqueous solutions using tri-octyl amine (TOA) in benzene as carrier

Abstract The recovery of anionic azo dyes namely Congo red (CR), methyl orange (MO) from acidic aqueous solutions using tri-octyl amine (TOA) as an extractant has been investigated. The percentage of extraction of MO and CR increases with an increasing TOA concentration. The anionic dyes were extracted from aqueous solution at pH 2.0 ± 0.1. The extracted dye has been back extracted into aqueous solutions using sodium hydroxide, sodium carbonate and sodium bicarbonate. The organic phase obtained after the stripping of dyes was washed with dilute sodium hydroxide solution to neutralize any sulphuric acid trapped or adhered to the solvent and then with distilled water. This solvent was reused in succeeding extraction of dyes. The influencing parameters were; the effect of diluents, effect of extractant concentration, effect of pH, effect of interference study, effect of equilibrium time, various stripping reagents and stripping phase ratio. The characterization studies such as UV and IR spectra of extracted and stripped MO and CR was also studied.

Extraction of Chloride Ions from Zinc-Bearing Waste Lixivium by Trioctyl Amine (TOA)

This paper presents research on separating Cl− from zinc-bearing waste lixivium by using trioctylamine as an extractant, 2-octanol as a solvent, and sulfonated kerosene as a diluent. The effects of trioctylamine concentration, organic/aqueous phase ratio, extracting stages, and waste lixivium pH were investigated, and the process of stripping was also discussed. The optimal conditions were achieved. The extraction efficiency, separation factor, and stripping efficiency were calculated with optimal values of 99.47%, 595, and 99.99%, respectively. Besides, the extractant regenerated after stripping was observed without the emulsifying phenomenon. The mechanism of extraction and stripping was also discussed.

Reactive extraction of acrylic acid using trioctylamine (TOA) in versatile diluents

AbstractHerein, since the extraction of organic acids is very important for recovery, acrylic acid was investigated from aqueous solutions by different diluents of trioctylamine (TOA). The extraction of acrylic acid with TOA dissolved in various individual solvents has been worked. Solvents have selected as dimethyl phthalate (DMP), cyclohexyleacetate (CHA), methyl isobutyl ketone, 2-octanone, 1-octanol, and 1-decanol. The experimental results of experiments are reported as distribution coefficients, D, loading factors, Z, and extraction efficiency, E. It is essential to improve extraction by adding extractant. The maximum removal of acrylic acid is 97.32% with DMP 1.15 mol/kg initial concentration of TOA. Here in, the LSER model has been applied to TOA + alcohol systems on extraction of acrylic acid to make predictions of distribution coefficient.

A novel approach for itaconic acid extraction: Mixture of trioctylamine and tridodecylamine in different diluents

Abstract Extraction of itaconic acid has been investigated from aqueous solutions by six kind of different solutions of trioctylamine (TOA)–tridodecylamine (TDA) mixtures. Solvents have selected as dimethyl phthalate (DMP), methyl isobutyl ketone (MIBK), 2-octanone, 1-octanol, cyclohexyleacetate (CHA), and 1-decanol. Distribution and equilibrium data for design of separation equipments have been obtained as a result of batch extraction of itaconic acid. It has been calculated that distribution coefficients (D), loading factors (Z), extraction efficiency (E). The maximum removal of itaconic acid has been obtained as 98.39% with DMP and 3.14 mol L−1 initial concentration of TOA–TDA mixture.

The Separation and Concentration of Titanium(IV) from Sulfuric Acid Solution with Trioctylamine

This paper presents research on separating and concentrating titanium(IV) from aqueous sulfuric acid solution, using trioctylamine (TOA) as extractant and kerosene as a diluent. We investigated the effects of reaction time, temperature, sulfuric acid concentration, organic/aqueous phase ratio, TOA concentration, and titanium concentration on the removal efficiency of titanium(IV). The results show that it is possible to recover over 99% of titanium(IV) after 15 min reaction time by TOA from the sulfuric acid solution under the optimum operation conditions and the loading capacity of TOA for titanium(IV) is 30 g Ti(IV)/100 g TOA. We expect that results studied would be applicable to separate and concentrate titanium from secondary sources such as red mud produced in the aluminum/alumina industry.

Extraction of 2-chloroethanol from aqueous solutions by trioctylamine

Abstract The trioctylamine (TOA) with kerosene as a diluent was used to separate 2-chloroethanol from aqueous hydrochloride acid solution. The stoichiometry of complex data was studied with infrared spectroscopic and the result shows that the ratio of 2-chloroethanol to amine in the complex was 1:2. The equilibrium constant was assumed to be 4.05 × 10 5 . Effects of temperature, equilibrium pH, TOA concentration, organic phase to aqueous ( O/A ) phase ratio and contact time on extraction yield of 2-chloroethanol were investigated. The results show that extraction yield can reach 58.2% under the optimum conditions.

Effective separation of iron from titanium by transport through TOA supported liquid membrane

Abstract Separation of iron from titanium acidic solutions with tri-octylphosphine oxide (TOPO) and trioctylamine (TOA) has been investigated. TOA was found to be more selective for extraction of Fe compared with TOPO from HCl concentrations >1 M. Iron could be stripped effectively from the loaded TOA in 1 M HClO 4 . Parameters affecting the transport separation of iron from titanium ions have been studied using a supported liquid membrane impregnated with TOA in kerosene. HCl and HClO 4 were used as feed and product solutions, respectively. Transport curves have been developed and Fe transport rate constant, k f , together with the time of 99.9% transport, t 99.9 , have been estimated. At 1 M HCl, 25 °C and 0.46 M TOA, Fe and Ti were practically not transported. By increasing the HCl concentration, the Fe transport was greatly improved where the t 99.9 reached 96 h at 5 M HCl. The Fe transport was further improved by rising the TOA concentration to 1.15 M and the temperature to 80 °C. Under these conditions about 80% of Fe was transported after only 1.5 h and the t 99.9 reached 6.4 h without any significant co-transport of Ti ions. The transport process seemed to be controlled by diffusion in the organic phase through the membrane since increasing the temperature enhanced the Fe transport. Although, direct leaching of ilmenite in HCl is known to be very limited, transport separation of Fe from the slurry by the present TOA-membrane system has lead to superior dissolution of Fe and Ti.

Chemical degradation of trioctylamine and 1-tridecanol phase modifier in acidic sulfate media in the presence of vanadium (V)

Abstract The chemical degradation of the mixture of trioctylamine (extractant) and 1-tridecanol (phase modifier) in n- dodecane in contact with acidic aqueous sulfate solutions containing vanadium(V) has been investigated. The degradation of trioctylamine and 1-tridecanol is slow at room temperature but is significant on a scale of years. GC–MS analyses show evidence of the formation of 1-tridecanal, dioctylamine, N,N,N-octen-1-yl-dioctylamine and an unidentified degradation compound which may contain a double bond and a carboxylic acid function. The global degradation rate of trioctylamine and 1-tridecanol increases sharply when sulfuric acid concentration decreases (0.1–1 mol kg − 1 H 2 SO 4 ) or when aqueous vanadium(V) concentration increases (0.02–0.1 mol kg − 1 V(V)). On the contrary, only a weak influence of trioctylamine concentration (0.2–0.5 mol kg − 1 ) and no significant influence of 1-tridecanol concentration (0.20–0.35 mol kg − 1 ) are observed. The formation of dioctylamine and N,N,N-octen-1-yl-dioctylamine arises from the presence of radicals generated by the oxidation of 1-tridecanol by vanadium(V). Several mechanisms of degradation are discussed on the basis of the identified degradation compounds.

Separation of 99Mo and 99mTc by liquid–liquid extraction using trioctylamine as extractant

Amongst various radionuclides of molybdenum, 90Mo and 99Mo have suitable β energy for clinical uses. In this paper we report separation of 99Mo from 99Mo-99mTc equilibrium mixture. The liquid–liquid extraction technique has been employed using trioctylamine (TOA) diluted in cyclohexane as organic phase and HCl as aqueous phase. At 10−5 M HCl and 0.5 M TOA concentration 99mTc quantitatively transferred to the organic phase leaving 99Mo in the aqueous phase. The developed separation method is efficient and provides very high separation factor.

Extraction of Monocarboxylic Acids with Trioctylamine: Equilibria and Correlation of Apparent Reactive Equilibrium Constant

Liquid−liquid equilibria for aqueous solutions of carboxylic acids, namely formic, acetic, propionic, butyric, valeric, monochloroacetic, dichloroacetic, trichloroacetic, glyoxylic, glycolic, and lactic acids, with trioctylamine (TOA) in various diluents, including 1-octanol, chloroform, methyl isobutyl ketone (MIBK), tetrachloromethane, and hexane, were determined at various TOA concentrations. The loading of TOA for a given carboxylic acid depends on the nature of the solute; the hydrophobicity and pKa of the acid; and the nature of solvent, diluent type, and TOA concentration, which can be expressed by the specific basicity of TOA (pK‘a,B), and increases with increasing acidity and hydrophobicity of the acid. The strength of solvation of the complex by the diluent for the acids studied decreases in the order 1-octanol ⩾ chloroform > MIBK > tetrachloromethane > hexane. An equilibrium model is presented that employs the mass action law and is used to determine model parameters and apparent extraction equilibrium constants (K11). The apparent extraction equilibrium constants depend on the hydrophobicity and acidity of the carboxylic acid, as well as the specific basicity of TOA, and the quantitative correlation of log K11 is obtained using log P, pKa, and pK‘a,B.

Synergistic extraction and separation of mixture of lanthanum and neodymium by hollow fiber supported liquid membrane

Separation of lanthanum and neodymium by supported liquid membrane has been studied. Synergistic extraction and recovery of lanthanum and neodymium with thenoyltrifluoroacetone (HTTA) in benzene have been found by the addition of Trioctylamine (TOA). Results indicate that percentage of extraction is highly dependent on pH of feed solution, which the maximum value is 2.5. When TOA was added to HTTA, the percentage of extraction and recovery considerably increased due to synergism. Lanthanum can be extracted and recovered more than neodymium because of the adduct formation constant,β 1 . Theβ 1 values decreased with an increase in atomic number of lanthanide and showed a difference between lanthanum and neodymium. Percentage of extraction and recovery is enhanced when the HTTA concentration is increased, but its difference is larger when TOA concentration is increased. Finally, multi-column module of supported hollow fiber membrane was used and the percentage and difference of extraction and recovery was found to be more increased due to resident time.

Integration of reactive membrane extraction with lipase‐hydrolysis dynamic kinetic resolution of naproxen 2,2,2‐trifluoroethyl thioester in isooctane

Lipases immobilized on polypropylene powders have been used as the biocatalyst in the enantioselective hydrolysis of (S)-naproxen from racemic naproxen thioesters in isooctane, in which trioctylamine was added to perform in situ racemization of the remaining (R)-thioester substrate. A detailed study of the kinetics for hydrolysis and racemization indicates that increasing the trioctylamine concentration can activate and stabilize the lipase as well as enhance the racemization and non-stereoselective hydrolysis of the thioester. Effects of the aqueous pH value and trioctylamine concentration on (S)-naproxen dissociation and partitioning in the aqueous phase as well as the transportation in a hollow fiber membrane were further investigated. Good agreements between the experimental data and theoretical results were obtained when the dynamic kinetic resolution process was integrated with a hollow fiber membrane to reactively extract the desired (S)-naproxen out of the reaction medium.