Trioctylamine Research Articles

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.

Extraction of Acetaminophen from Aqueous Solution by Emulsion Liquid Membrane Using Taylor-Couette Column

A study on the extraction of Acetaminophen (ACTP) which is also known as paracetamol, from aqueous solution by emulsion liquid membrane process using Taylor-Couette Column (TCC) was investigated. An ELM consists of three phase system which are the external, membrane and internal phases. The external phase containing the ACTP aqueous solution to be treated. Basically, the internal and membrane phase form the primary water-in-oil (W/O) emulsion using ultrasonic probe which is to be dispersed in the external phase. In this work, Trioctylamine (TOA), Span 80 and kerosene were used as carrier, surfactant and diluent, respectively in membrane phase. Meanwhile ammonia solution was used as a stripping agent in the internal phase. The influence of several operating conditions such as surfactant and carrier concentration, ultrasonic power, emulsification time, treat ratio, stirring time and stirring speed were investigated. The results showed that the present work proved that the ELM using TCC system was capable to effectively remove about 85 % ACTP from aqueous solutions under optimum conditions of 15 minutes of emulsification time, 6 wt.% of Trioctylamine and Span 80, 20 W power of ultrasonic probe, 5 minutes of extraction time, frequency angular ratio of 1.0 and treat ratio of 3:1.

The extraction of Cr (VI) from aqueous solution with a mixture of TEA and TOA as synergic extractant by using different diluents

Synergistic extraction of Cr (VI) from aqueous solution was performed by using a mixture of triethylamine (TEA) and trioctylamine (TOA) in different diluents. The maximum extraction of Cr (VI) was obtained as 98.95% with toluene as a diluent at optimum conditions. The various extractants were experimented to find out the suitable synergic mixture and their corresponding percentage extraction was reported. The influence of different analytical parameters such as pH, temperature, equilibrium time, initial concentration of Cr (VI), organic to aqueous (O/A) ratio was performed. Thermodynamic studies showed the process to be exothermic, and Gibb's free energy change and entropy change collectively indicated the extraction process to be reversible and spontaneous. The organic phase after the extraction process was characterized using FTIR spectroscopy which confirms a new ion pair formation. The organic phase containing the metal extractant can be regenerated using different reducing agents such as ascorbic acid, NaOH, etc. The effect of diverse ion of varying concentration was studied to find out their interference in the extraction process. The method was applied to the extraction of Cr (VI) from synthetic effluent as well as a real untreated tannery wastewater sample and the results were found to be satisfactory.

STUDY OF PREPARATION, GROWTH MECHANISM AND SERS PERFORMANCE OF SILVER-CARBON AND GOLD-CARBON NANOCOMPOSITE MATERIALS

Surface-enhanced Raman scattering (SERS) technique is an important and powerful analytical tool, which has attracted much attention for environmental monitoring, chemical analysis and biomedical research. In this paper, we develop a facile method to fabricate the silver-carbon nanocomposites (Ag/CSs) and gold-carbon nanocomposites (Au/CSs). The composites were prepared by one-step hydrothermal reduction method using trioctylamine (TOA) as the soft template and extractant. According to the different amount of TOA added, we prepared a different morphology of the composite material. When the amount of TOA is 1.0 mL, the core-shell composite was obtained. The shape of the silver core shows the hexagon shape and we consider that TOA and glucose selectively adsorb the Ag (111) crystal face resulting in this growth pattern of the silver core. The hydrothermal carbon shell not only effectively avoids the agglomeration of nanoparticles core, but also serves as a protective layer of the SERS active nanostructure during the whole course of the experiment. The detection limit of Ag/CSs for CV molecules up to 10−9 M. The results show that the as-obtained Ag/CSs hold tremendous potential for SERS applications for its long-term stability and superior SERS performance.

Speciation of Ruthenium(III) Chloro Complexes in Hydrochloric Acid Solutions and Their Extraction Characteristics with an Amide-Containing Amine Compound

The refining of platinum group metals is based mainly on solvent extraction methods, whereas Ru is selectively recovered by distillation as RuO4. Replacement of distillation by extraction is expected to simplify the purification process. To develop an effective extraction system for Ru, we analyzed the Ru species in HCl with ultraviolet-visible (UV-Vis) and Ru K-edge extended X-ray absorption fine structure (EXAFS) spectroscopies, and we examined the properties of Ru extracted with N-2-ethylhexyl-bis(N-di-2-ethylhexyl-ethylamide) amine (EHBAA) and trioctylamine (TOA). EXAFS and UV-Vis spectra of Ru in HCl solutions revealed that the predominant Ru species in 0.5–10 M HCl solutions changed from [RuCl4(H2O)2]− to [RuCl6]3− with the HCl concentration. The extraction percentages (E%) of Ru in the EHBAA system increased with increasing HCl concentration, reached 80% at [HCl] = 5 M, and decreased at higher HCl concentrations; the corresponding E% for TOA were low. EXAFS analysis of the extracted complex indicated that the Ru3+ had 5 Cl− and 1 H2O in its inner coordination sphere. The similarity of the dependence on HCl concentrations of the E% in the EHBAA system and the distribution profile of [RuCl5(H2O)]2− on [RuCln(H2O)6−n]3−n suggested that the EHBAA extracted the pentachlorido species.

Acetic Acid Removal from Pre-Pulping Wood Extract with Recovery and Recycling of Extraction Solvents.

Pre-pulping extraction is a means of deriving a hemicellulose-rich process stream from the front end of a kraft pulp mill. When the extraction is carried out using green liquor, pulp quality and quantity can be retained while still releasing hemicelluloses and acetic acid (HAc) for recovery as bioprocessing feedstock or chemical products. The HAc that is present in the wood extraction is inhibitory to microorganisms and can hinder fermentation. HAc is also a commodity chemical that may provide sufficient value to justify recovery and purification. In this study, a liquid-liquid extraction (LLE) method is applied to extract HAc from a green liquor pre-pulping hardwood extract (GLE). The HAc removal is carried out after acid hydrolysis and prior to fermentation. Two organic solutions: trioctylphosphine oxide (TOPO) diluted in undecane and trioctylamine (TOA) diluted in octanol were tested for their abilities to extract HAc from GLE and to be recycled back through the process. GLE was contacted with the organic solvents, phase separated by centrifugation, and the organic phase was then distilled to recover the acetic acid. The solvent was then recycled back for a subsequent extraction of fresh GLE. It was found that TOA was a superior extractant, but failed to easily release its HAc through distillation. It also quickly became contaminated with other compounds in the wood extracts and lost its extraction efficiency after only a few recycles. The TOPO solvent did release its HAc through distillation but also lost extraction capacity with recycling. Back extraction of the TOPO solvent with sodium hydroxide solution restored the performance of the TOPO solvent.

Production and separation of no-carrier-added 181−184Re radioisotopes from proton irradiated tungsten target

Abstract Cross sections for the production of 181−184Re isotopes from proton irradiated thin natWO3 target at 20.9, 17.9, 14.9, 11.9 and 8.8 MeV projectile energies have been measured. An acceptable agreement between experimentally obtained data and available literature reports was found. The produced no-carrier-added (NCA) Re radionuclides have been separated from bulk tungsten target by liquid-liquid extraction (LLX) using trioctyl amine (TOA) and di-(2-ethylhexyl)phosphoric acid (HDEHP) dissolved in cyclohexane. A clear separation has been observed at 0.1 M and 1 M TOA with 0.1 M HNO3 concentration. However, by using HDEHP NCA Re radionuclides could not be separated from bulk W target without its contamination.

Solvent Selection for Extraction of Neodymium Concentrates of Monazite Sand Processed Product

The extraction of neodymium concentrates of monazite sand processed product has been done. The objective of this investigation was to determine the best solvent to separate Nd from Nd concentrate. As an aqueous phase was Nd(OH)3 concentrated in HNO3 and as solvent or the organic phase was trioctylamine (TOA). tryibuthyl phosphate (TBP). trioctylphosphine oxyde (TOPO) and di-ethyl hexyl phosphoric acid (D2EHPA) in kerosene. The investigated variables were HNO3 concentration. feed concentration. solvent concentration or solvent in kerosene. time and stirring speeds. From the investigation on the selection of solvent for the extraction of Nd(OH)3 concentrate with various solvents. it was concluded that the extraction of Nd could be carried out by using TBP or TOA. Extraction of Nd using TOA at the optimum HNO3 concentration of 2M. feed concentration of 5 gram/10 mL. TOA in kerosene concentration of 6 %. stirring time of 15 minutes. stirring speed of 200 rpm was chosen if the Y concentration in Nd concentrate is small. In these condition DNd obtained was 0.65; extraction efficiency of Nd (ENd)=37.10%. the concentrations of Nd2(C2O4)3 = 67.14%. Ce2(C2O4)3 = 1.79%. La2(C2O4)3 = 1.37% and Y2(C2O4)3 = 24.70%. Extraction of Nd using TBP at the optimum HNO3 concentration of 1M. feed concentration of 5 gram/10 m. the TBP concentration in kerosene of 15%. stirring time of 15 minutes and stirring speed of 200 rpm was chosen if the Ce concentration in Nd concentrate is small. In these condition DNd obtained was 0.20. extraction efficiency of Nd (ENd)=17%. concentration of Nd2(C2O4)3 = 70.84%. Ce2(C2O4)3=15.53%. La2(C2O4)3 = 0.00% and Y2(C2O4)3 = 8.63%.

Study on extraction behavior of vanadium from acidic sulfate solutions

Extraction behavior of vanadium (V(V)) from the acidic sulfate solutions was investigated using trioctylamine (TOA). The extraction efficiency of V(V) from the acidic sulfate solutions increased with increase of pH value, extractant concentration and O/A phase ratio. The optimum condition for V(V) extraction from the acidic sulfate solutions containing 100 mg/L V(V) was found to be at pH 2.5 using 0.005 M TOA. The V(V) from the loaded TOA was completely stripped by the use of 0.5 M NaOH solution. The regeneration of TOA after stripping process was obtained by washing with distilled water and the recycling capacity of regenerated TOA was no appreciable change.

Selective sorption and separation of molybdenum ion from some fission products by impregnated perlite

Molybdenum is a vital element in the industry and biological systems, and for environmental protection, it is needed to remove molybdenum ion from the wastewater. Therefore, this work focused on removal and separation of molybdenum ion from some fission products such as La(III), Eu(III), Ce(IV) and Y(III) ions. For this purpose, perlite was impregnated by trioctyl amine, characterized using XRF, SEM, FT-IR and XRD and used for the sorption and separation processes. Sorption behavior of these ions was investigated by the batch method. The impregnation process of perlite enhanced the percent uptake of Mo(VI) from 3.6 to 93.2%. Furthermore, separation tests using simulated waste solutions containing the mentioned fission products were carried out to verify the possibility of the separation process. The breakthrough curve of Mo(VI) had S-shaped profile, and the elution percentage was estimated to be 98.6% by 1.0 mol/L H2SO4. The obtained results revealed that the proposed process is essentially feasible.

Extraction of Ethylparaben by emulsion liquid membrane: Statistical analysis of operating parameters

Ethylparaben, alkyl esters of p-hydroxybenzoic acid, is an endocrine disruptor that interfere glandular activity and hormone production and even with considerable elimination of them using conventional treatment methods, it is still recognized in river water samples at high concentrations. In this study, Emulsion Liquid Membrane (ELM) consisted of trioctylamine (TOA) as carrier, n-heptane as diluent, Span 80 as surfactant and Na2CO3 as the stripping solution was used for the removal of ethylparaben (EP) from aqueous solution. Studies were conducted to analyse the effect of various operating parameters. Effect of factors like carrier concentration (C), stripping phase concentration (N), speed of homogenizer (H), surfactant concentration (S) on the extraction of EP were evaluated with Taguchi's method. Statistical analysis of variance (ANOVA) was applied to analyze the effect of each parameter and stripping phase concentration (0.5 N Na2CO3) followed by speed of homogenizer (13500 rpm) were found to be the most influencing parameters. Photomicrographs of emulsions and droplet size analyzer were used to study the impact of speed of homogenizer on emulsion droplet size and size distribution. Dispersion destabilization of the emulsion was detected by Turbiscan. Atomic force microscopy and Fourier transform infrared spectroscopy were used to analyse dimensions, shape of emulsion droplet and also to confirm bonding and the presence of different functional groups. Experimental design for multivariable optimization by Taguchi had also been implemented. Using a stable emulsion at optimum condition ∼90% extraction of EP was achieved.

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.

Preparation and characterization of Ag@C composites with hexagon silver core and controllable carbon shell for surface-enhanced Raman scattering

Here, novel and stable core–shell silver–carbon nanocomposites (Ag@CSs) were obtained using glucose as the carbon source and stabilizer, silver nitrate as the silver source, and trioctylamine (TOA) as the soft template and extractant. It is worth mentioning that the shape of the silver core shows the hexagon shape, and we consider that TOA and glucose selectively adsorb the Ag (111) crystal face resulting in this growth pattern of the silver core. Owing to the enhanced local field effect around their sharp corners and edges, such structure exhibits superior properties for the surface-enhanced Raman scattering (SERS) enhancement. The hydrothermal carbon shell not only effectively avoids the agglomeration of Ag nanoparticles core, but also serves as a protective layer of the SERS active nanostructure during the whole course of the experiment. In addition, the thickness of the loose shell was significantly reduced after the product was stored in ethanol solution for a period of time. It is found that dropped cast probe molecules onto Ag@CSs have a lower SERS activity, while that immersed in the probe molecular solution for a period of time have a higher SERS activity, indicating that the detection of the probe molecules using this Ag@CSs substrate may require an interactive process. The results show that the as-obtained Ag@CSs hold tremendous potential for SERS applications for its long-term stability and superior SERS performance.

Recovery of germanium from waste Optical Fibers by hydrometallurgical method

With the rapid development of optical fiber communications industry, germanium as main raw materials of optical fiber cables become more important in recent years. Due to the scarcity and importance of germanium, we developing an effective recycling process of recovering germanium metal from waste fiber optic cables. The process was arranged to do pre-treatment, leach the fiber and extract the germanium from silicon. In the leaching step, the concentration of different acid, reaction time and liquid-solid ratio were investigated. At the solvent extraction process, the pH value, concentration of extractant and stripping agents, organic-aqueous ratio and reaction time were considered. In leaching step, germanium and silicon were dissolved in solution by sulfuric acid and hydrofluoric acid. Then, germanium was extracted by Trioctylamine (TOA) to the organic phase and silicon was remained in the aqueous by controlling the conditions. After then, Germanium was then stripped by sodium hydroxide. With the optimal conditions, the recovery of germanium could be up to 99%. After separation, germanium could be recycled to back to the industrial effectively.

Architecture of designed hollow indium oxide microspheres assembled by porous nanosheets with high gas sensing capacity

Gas sensing properties could be remarkably enhanced by self-assembly of zero, one or two dimensional nano-size units into three dimensional (3D) complicated superstructures. In this work, the 3D hollow indium oxide (In2O3) microspheres (HIOMs) assembled with porous 2D sheets were successfully synthesized by solvothermal method in Oleic acid (OA) and trioctylamine (TOA) system with the help of glycerine (Gl) combined with subsequent heat treatment. The density of self-assemble porous 2D nanosheet could be regulated by changing the calcination temperature from 400 °C to 600 °C. The gas-sensing performance of the as-prepared HIOMs had been measured towards unstable organic compounds containing methanol, acetone, ethanol, dichloromethane (DCM) and tetrahydrofuran (THF). Experimental results revealed that HIOMs-400 showed the highest response and selectivity to ethanol, followed by HIOMs-500 and HIOMs-600. At an ethanol concentration of 600 ppm, the HIOMs-400 sensor had a sensitivity of up to 15.6, while the sensitivity was about 11.9 for HIOMs-500 and 6.7 for HIOMs-600. HIOMs-400 also presented long term stability and repeatability even after five months. Such outstanding gas sensing properties of HIOMs-400 benefited from the larger BET surface area, denser pore structure and excellent capabilities of surface adsorbed oxygen.

Experimental Investigation on Microfluidic Reactive Extraction of Citric Acid Using Trioctylamine/1-Decanol System in Uniform and Nonuniform Circular Microchannels

Dilute citric acid solutions were extracted with trioctylamine (TOA) in 1-decanol at ambient conditions using indigenous microfluidic setup with 0.8 mm section diameter. In these slug/segmented flow reactive extraction processes with equal flow ratios, the channel lengths were varied from 10 to 40 cm, and the flow rates used were in a spread of 10 to 60 mL/h. The extraction characteristics were analyzed in terms distribution coefficient, extraction percentage, and change in concentration of the aqueous phase. The results were compared with the literature data of conventional reactive extraction and found that the microfluidic system was performing well on the basis of residence time. Effort had also been made to present indicative results of the system performance in a nonuniform microfluidic channel provided with a number of intermittent 1.6 mm diameter expansions. It had been found that the flow in nonuniform channels can deliver higher efficiencies and distribution coefficients.

Study of Preparation, Growth Mechanism and Catalytic Performance of Carbon Based Embedded Silver Nano Composite Materials

Novel and stable carbon based embedded silver nano composite materials (Ag/CSs) were successfully prepared by a facile one-pot hydrothermal method with trioctylamine (TOA) as soft template and stabilizer. These as-prepared Ag/CSs exhibit well-defined shape and relatively uniform size with an average diameter of 1.5 μm and uniformly embedded Ag nanoparticles about 5 nm. The proper proportion of glucose, AgNO3 and TOA is the key to the common growth of hydrothermal carbon materials and silver nanoparticles in an embedded way. Besides, the thickness of carbon sphere matrix and the size of Ag particles can be tailored precisely by adjusting the experimental parameters. In order to facilitate comparative analysis, carbon spheres (CSs) without Ag particles embedded were also prepared with glucose under the same hydrothermal reaction conditions. The composition, structure and morphology of the as-prepared Ag/CSs and CSs were confirmed by X-ray powder diffraction (XRD), FT-IR spectroscopy, Raman spectrum, Transmission electron microscopy (TEM) and scanning electron microscopy (SEM). In addition, the possible formation mechanism of the Ag/CSs has been proposed based on experimental evidences. Finally, the as-prepared Ag/CSs and CSs were used as catalysts in the experiments of photocatalytic degradation of methylene MB in water under visible light irradiation and the high efficiency of photocatalytic performance of Ag/CSs has been verified.

High anisotropic NdFeB submicro/nanoflakes prepared by surfactant-assisted ball milling at low temperature

Hard magnetic NdFeB submicro/nanoflakes were successfully prepared by surfactant-assisted ball milling at low temperature (SABMLT) by specially using 2-methyl pentane and trioctylamine (TOA) as solvent and surfactant, respectively. Influences of the amount of TOA and milling temperature on the crystal structure, morphology and magnetic performances of the as-prepared NdFeB powders were investigated systematically. There is significant difference on morphology between the NdFeB powders milled at room and low temperature. The NdFeB powders with flaky morphology could be obtained even with a small amount of TOA by SABMLT, which could not be achieved by surfactant-assisted ball milling at room temperature (SABMRT). The better crystallinity, better grain alignment, higher coercivity, larger saturation magnetization and remanence ratio were achieved in the samples prepared by SABMLT. Furthermore, the final NdFeB powders prepared by SABMLT possessed a lower amount of residual TOA than those prepared by SABMRT. It was demonstrated that SABMLT is a promising way to fabricate rare-earth-transition metal nanoflakes with high anisotropy for permanent magnetic materials. The effective method of preparing NdFeB flakes by lowering temperature will be also useful to fabricate flakes of other functional materials.

Solvent Extraction of Polonium(IV) with Tributylphosphate (TBP)

ABSTRACTThe extraction mechanism of Po(IV) from hydrochloric acid (HCl) solution by tributylphosphate (TBP) and trioctylamine (TOA) was investigated as a function of acid (0.1–12 mol/kg) and extracting agent (0.36–3.64 M) concentrations. Experimental data were modeled to determine the extraction mechanisms as well as the associated thermodynamic constants. Preliminary extraction experiments were carried out using tri-n-octylamine (TOA) in order to determine the activity-corrected Ringbom coefficient in concentrated HCl. The results showed the existence of a species involving two TOA molecules, , which dominated organic polonium speciation in concentrated HCl (9–12 mol/kg). Then, we determined the complexation coefficient of as a function of HCl concentration in order to calculate molality for a known total concentration of polonium. The obtained information was used to determine the extraction mechanism occurring in the presence of TBP. The theoretical model agrees with the experimental results considering the existence of the following extracted polonium species: and in the acidic ranges of 0.1–1 and 2–9 mol/kg, respectively. Another extracted species seems to exist in intermediate HCl molality. However, the number of TBP molecules and the associated thermodynamic extraction constant could not be determined. Taken together, the data enable us to propose that the extraction scheme of polonium by TBP corresponds to the following two reactions: