Feed Phase pH Research Articles

Extraction of propionic acid by emulsion liquid membrane using trioctylamine in toluene

The extraction of carboxylic acids by emulsion liquid membranes has also attracted attention in biotechnology, due to the high selectivity for the desired product, high separation rate and lower costly. The emulsion type liquid membrane system consists of three phases (water/organic/water) in which the organic phase acts as a membrane between the aqueous internal phase and the aqueous external phase. The main parameters such as surfactant concentration, mixing speed, feed phase pH, carrier concentration, and feed phase concentration were investigated. In the optimum conditions, extraction efficiency was obtained 71% in 10 minutes using trioctylamine (5% w/w) as a carrier, Span 80 (4% w/w) as a surfactant, toluene (91% w/w) as a diluent, sodium carbonate (10% w/w) as a stripping solution, mixing speed 300 rpm and feed phase pH 2,5.

The recovery of rare earth metals from WEEE leaching solution via liquid-liquid extraction

<p>The recovery of rare earth metals (REMs) from end-of-life products, such as Waste Electrical and Electronic Equipment (WEEE), is drawing great attention as an attractive strategy for promoting the sustainable development. The hydrometallurgical technique of solvent extraction has been reported to be one of the most interesting method to recover REMs. However, when applied to WEEE, this process is challenged by the heterogeneous composition of electronic waste, completely different from other solid matrices, and it still has much rooms of improvements. This study investigated the extraction, stripping and recovery of REMs from a WEEE leaching solution using Versatic 10 as carrier in the organic phase and oxalic acid as stripping agent. A factorial design was carried out to evaluate the simultaneous effects of factors as the feed phase pH and the concentrations of both extractant and organic phase modifier in the extraction process. Cerium, lanthanum and yttrium were extracted at high percentages using 200 mM of Versatic 10, loaded by 100 mM of TBP in kerosene at pH 7. Moreover, 750 mM of oxalic acid successfully stripped and recovered 7.63 and 13.82 mg/kg of lanthanum and yttrium, respectively.</p>

Efficient extraction and recovery of Lignosulfonate using sunflower oil as green solvent in liquid membrane transport: Equilibrium and kinetic study

This work highlights extraction and removal of Lignosulfonate using sunflower oil-Tri-n-octylamine (TOA) system in bulk liquid membrane transport. Maximum extraction and recovery percentages of 92.4% and 75.2% were achieved. Optimum manifold operating conditions were: 4vol.% TOA, 2±0.1 feed phase pH, 300rpm stirring speed, at 40°C with 0.2 (M) Na2SO4 solution. 1:2 (organic/aqueous) and 1:1 (aqueous/aqueous) phase ratios produced best results. Extraction (36.85kJ/mol) was found to be intermediate controlled and stripping (54.79kJ/mol) was chemical reaction controlled. Kinetic estimation of data with higher rate constants for stripping vis-à-vis extraction showed latter to be rate determining.

Evaluation of activated composite membranes for the facilitated transport of phenol

Abstract In this work the results on the first use of an activated composite membrane (ACM) containing Cyanex 923 for the extraction and transport of phenol are presented. A new dense layer-ACM configuration constituted by piperazine showed better stability than that prepared with 1,3-phenylenediamine. The effects of several parameters on the transport of phenol such as feed phase pH, carrier concentration and stripping phase composition were evaluated. The performance of the membrane was also evaluated during continuous additions of phenol and for a long period of time, observing the same rate of extraction and reextraction. Moreover, phenol transport was evaluated starting from synthetic wastewater of resin production plants type. The results exhibit the potential use of ACMs in the elimination and transport of organic species, even when analyte is initially found in complex solutions.

Evaluation of the emulsion liquid membrane performance on the removal of gadolinium from acidic solutions

This work evaluates the performance of emulsion liquid membrane (ELM) for the extraction of gadolinium(III) from acidic solution. The ELM was made up of di-(2-ethylhexyl) phosphoric acid (D2EHPA) as carrier, Span 80 (sorbitol monooleate) as emulsifying agent, commercial kerosene as organic diluent and Nitric acid as stripping phase. Important physical and chemical variables affecting the ELM performance for the extraction of gadolinium(III) such as carrier concentration, mixing time, surfactant concentration, agitation speed, initial pH of the feed phase, internal phase concentration, treatment ratio, and feed phase concentration were systematically investigated. Results indicated that the highest gadolinium(III) extraction can be attained after 10 min of mixing by using 0.05 M D2EHPA, 1.5% (v/v) Span 80, 1.0 M nitric acid as stripping phase at feed phase pH of 2, agitation speed of 180 rpm, and treatment ratio of 1:10. At the optimum condition, simultaneous quantitative extraction (>99%) and stripping (>79%) of gadolinium were achieved. Furthermore, the overall mass transfer coefficient was calculated and the results revealed that the extraction was interfacially controlled.

Effective removal of Congo red using sunflower oil/tri-n-octylamine system in a bulk liquid membrane process and studying the transport kinetics

The present work highlights effective transport and removal of Congo red (CR) from its model solution using sunflower oil/tri-n-octylamine (TOA) system in bulk liquid membrane (BLM) transport. Aqueous solution of Na2CO3 with 1 M solution strength was found to be an effective stripping medium for the anionic dye transport. Maximum extraction and recovery percentages of 99.9 and 75.6% were achieved when optimum manifold operating conditions were: 4 vol.% TOA, 2 ± 0.1 feed phase pH, 300 rpm stirring speed, at 40 °C temperature with 8 h, equilibrium time. Kinetic estimation of data with higher rate constants for extraction vis-a-vis stripping operation throughout various experimental conditions suggested that CR transport across sunflower oil/TOA BLM system was governed by stripping process. Activation energies for extraction and stripping operations were found to be 45.92 and 74.05 kJ mol−1, respectively. This led to a conclusion that the rate determining step for extraction was intermediate controlled whereas for stripping it was chemical reaction rate controlled. Finally, spectral studies (UV–vis and FT-IR) were carried out to confirm and validate the recovery of CR.

Reverse micelle Extraction of Antibiotics using an Eco-friendly Sophorolipids Biosurfactant

Reverse micelles extraction of erythromycin and amoxicillin were carried out using the novel Sophorolipids biosurfactant. By replacing commonly used chemical surfactants with biosurfactant, reverse micelle extraction can be further improved in terms of environmental friendliness and sustainability. A central composite experimental design was used to investigate the effects of solution pH, KCl concentration, and sophorolipids concentration on the reverse micelle extraction of antibiotics. The most significant factor identified during the reverse micelle extraction of both antibiotics is the pH of aqueous solutions. Best forward extraction performance for erythromycin was found at feed phase pH of approximately 8.0 with low KCl and sophorolipids concentrations. Optimum recovery of erythromycin was obtained at stripping phase pH around 10.0 and with low KCl concentration. On the other hand, best forward extraction performance for amoxicillin was found at feed phase pH around 3.5 with low KCl concentration and high sophorolipids concentration. Optimum recovery of erythromycin was obtained at stripping phase pH around 6.0 with low KCl concentration. Both erythromycin and amoxicillin were found to be very sensitive toaqueous phase pH and can be easily degraded outside of their stable pH ranges.

Application of Bulk Liquid Membrane Technique for Cadmium Extraction from Aqueous Solution

The extraction of cadmium from aqueous solution using kerosene as a bulk liquid membrane (BLM) with Tri-n-butyl phosphate (TBP) as a carrier was experimentally investigated under various operating conditions. The effects of feed and strip pH, feed initial concentration, TBP concentration, and strip to feed volume ratio on the cadmium ions transport efficiency were investigated. A stripping agent EDTA was used to enhance the transport efficiency of the cadmium ions. Flax and sesame oils were also considered as green liquid membrane alternatives to kerosene. They were evaluated in terms of extraction and separation efficiency. Cadmium extraction and stripping efficiencies of 89 and 94% were, respectively, obtained under specific conditions (100 ppm initial concentration of cadmium ions, 10% (v/v) TBP concentration, (1:2) strip to feed volume ratio, feed phase pH of 3, and strip phase pH of 11). The kinetics of $$\hbox {Cd}^{2+}$$ transport across BLM was investigated using kinetic model derived from the kinetic law of two consecutive irreversible first-order model. Both flax and sesame oils were found less efficient than kerosene in cadmium extraction and stripping rates.

Acquisition of Co metal from spent lithium-ion battery with emulsion liquid membrane technology using cyanex 272 as extractant

Lithium-ion batteries are the most common type to be used as energy source in mobile phone. The amount of lithium-ion battery wastes is approximated by 200 – 500 ton/year. In one lithium-ion battery, there are 5 – 20% of cobalt metal, depend on the manufacturer. One of the way to recover a valuable metal from waste is leaching process then continued with extraction. Spent lithium-ion batteries will be characterized with EDX and AAS, the result will show the amount of cobalt metal with form of LiCoO2 in the cathode. Hydrochloric acid 4 M, temperature 80°C, and reaction time 1 hour condition give out the best leaching efficiency for both Co and Mn metals, 88.54% and 89.28% respectively. For extraction, the best extraction efficiency achieved when feed phase pH is 5 for Co and 6 for Mn. This study will discuss the leaching and extraction process and compare the efficiency for both processes.

Selective separation and enrichment of neodymium and gadolinium by emulsion liquid membrane using a novel extractant CYANEX® 572

In present study, the novel commercial extractant, CYANEX® 572, was applied for selective separation and enrichment of neodymium and gadolinium through an emulsion liquid membrane. Response surface methodology (RSM) based on central composite design (CCD) is carried out to explore the relationships between process variables namely, carrier concentration, initial pH of feed phase, surfactant concentration and mixing speed, and their interactions. The contours and 3D response surfaces of selective extraction of Gd(III) were achieved and significance of four important variables and their interactions on extraction efficiency of Gd(III) and Nd(III) and separation factor were found out. Also, three regression models for them were developed. A multiple optimization was performed to evaluate the best possible goals for the responses, simultaneously. Results indicated that the maximum separation factor of Gd(III) over Nd(III) was achieved using 0.75 M CYANEX® 572 as minimum concentration of carrier, initial feed pH of 1.56, surfactant concentration of 4% (v/v) and mixing speed of 135 rpm. Under the optimum condition, the extraction percentage of Gd(III) was maximum (67.45%), while the extraction percentages of Nd(III) was minimum (28.98) and the separation factor was found to be 3.78. Under the optimized condition, further experiments were conducted to investigate the effect of hydrochloric acid as internal stripping phase on the stripping efficiencies and enrichment factors were examined. At the internal concentration of 0.5 M, the stripping efficiency and enrichment factor reached the maximum of 89.04% and 12.01 for Gd(III), and 19.45% and 1.13 for Nd(III).

Separation and Recovery of Cadmium(II) from Wastewater of Zinc Mining by Using Hollow Fiber Supported Liquid Membrane

The extraction and recovery of cadmium(II) via a hollow fiber supported liquid membrane (HFSLM) containing D2EHPA as a carrier dissolved in kerosene. The various effects on extraction and recovery cadmium were studied pH of feed phase, concentration of extractant and pH of stripping phase. The extraction and recovery of cadmium by using the hollow fiber supported liquid membrane method were 97% and 57%, respectively. The transport of cadmium ions was achieved by driving force of the concentration gradient. The behavior of extraction and/or recovery in HFSLM could be demonstrated in mass-transfer coefficient among feed phase, membrane phase and stripping phase. Determining the limiting step controlling the mass transfer of cadmium ion used the permeability coefficient.

Emulsion ionic liquid membrane for recovery process of lead. Comparative study of experimental and response surface design

The technique of emulsion ionic liquid membrane (EILM) was used as chemical process for Pb(II) recovery, from nitrate medium, using Aliquat336 as ionic liquid carrier. The Tween20 as a dispersive non-ionic surfactant was used for the emulsion formation. The optimization of the extraction and pre-concentration of Pb(II) was determined by optimizing one parameter at the time. So, several experimental parameters as: carrier concentration, surfactant concentration, time and stirring speed of feed phase, initial concentration and pH of feed phase, were studied. The results showed that the lead ions were extracted at 82.61% by Aliquat336 and recovered at 82.16%, in aqueous solution of the nitric acid, from a feed phase of lead(II) nitrate of 207.2ppm at pH equal to 5.5, in presence of 1% w/w Aliquat336 and 0.5% w/w of Tween20 under 30min of stirring at 210rpm. The tests of separation experiments of Pb(II) and Cu(II) were carried on the basis of the optimal conditions of lead (II) recovery. Thus, the separation factor of lead over copper was equal to 1.30, obtained from their equimolar synthetic mixture. Indeed, the recovery of Cu(II) can be advantageous towards of Pb(II) if the molar composition of Cu/Pb in mixture was of 0.65. Response surface methodology (RSM) using Box–Benheken Design (BBD) was used for the statistical study. So, the reduced cubic of the quadratic model showed that the predicted values were in good agreement with those found experimentally and the parameter of ionic liquid concentration has an important individual effect on the response. Therefore, the recovery of Pb(II) can be predicted at 82.14% with the best desirability of the chosen model under our experimental conditions.

Selective extraction of dysprosium from acidic solutions containing dysprosium and neodymium through emulsion liquid membrane by Cyanex 572 as carrier

The selective extraction of Dysprosium (Dy) from acidic solutions also containing Neodymium (Nd) was studied using an Emulsion liquid membrane (ELM). Cyanex 572 was successfully applied as carrier. The liquid membrane phase consists of kerosene as diluent, Span 80 as surfactant, Cyanex 572 as carrier, and hydrochloric acid solution as stripping phase. Initially, the effects of different parameters such as carrier concentration, stirring speed, feed phase pH, surfactant concentration and their interactions on Dy extraction were investigated and the values of them were optimized by response surface methodology. Based on the results, the role of pH is very important in the ELM process for extraction of Dy by Cyanex 572. Thereafter, the selectivity of the membrane, represented by extraction, enrichment, and separation factor, was analyzed systematically with a view to optimizing the emulsion stability. The effect of important operating parameters governing the extraction and selectivity in ELM process namely feed phase pH; carrier and stripping phase concentration, initial concentration of Dy and Nd, and time of extraction have been investigated. It was found that it is possible to selectively extract 98.99% of Dy from the acidic feed solution containing Dy and Nd though ELM after 10min and maximum enrichment and separation factor can be achieved under the optimum conditions.

Application of emulsion nanofluids membrane for the extraction of gadolinium using response surface methodology

In this work, an emulsion nanofluid membrane (ENM) was applied to effectively extract gadolinium. Simultaneous emulsification of nanoparticles and surfactant was performed to stabilize the ENM. Multi-walled carbon nanotubes (MWCNTs) nanofluid was employed as liquid membrane. The ENM composed of diisooctylphosphinic acid (CYANEX 272) as carrier, MWCNTs as nanoparticles, Span-85 (sorbitan triooleate) as surfactant, kerosene as organic diluent and nitric acid as internal phase. The effects of important operating variables i.e., carrier concentration, MWCNTs concentration, surfactant concentration, mixing speed, internal phase concentration and feed phase pH were investigated. Response surface methodology (RSM), according to central composite design (CCD), is used to optimize the process variables and a regression model for extraction percentage was developed. The 3D response surfaces of gadolinium (III) extraction efficiency were achieved and significance of six important variables and their interactions on extraction efficiency were found out. The desirability function was performed to simultaneously evaluate all the factors and determine the best possible goals for each response. The optimum condition for gadolinium extraction were: The optimum condition for gadolinium extraction were: 0.84M of CYANEX 272, MWCNTs concentration of 318.05ppm, 2.91% (v/v) of Span-85, mixing speed of 188.15rpm, 1.27M of HNO3 as internal phase reagent, feed phase pH of 3 and desirability value of 0.904. Under the optimized condition, the extraction of Gadolinium (III) reached the maximum of 92.05%.

Transport and selectivity of indium through polymer inclusion membrane in hydrochloric acid medium

In the present paper, a polymer inclusion membrane (PIM) containing polyvinyl chloride (PVC), and bis-(2-ethylhexyl) phosphate (D2EHPA) which was used as extracting agent was used for the recovery of In(III) ions in hydrochloric acid medium. The effects of carrier concentration, feed phase pH, strip phase HCl concentration, temperature on the transport, and the membrane’s stability and thickness were examined. And the conditions for the selective separation of In(III) and Cu(II) were optimized. The results showed that the transport of In(III) across PIM was consistent with the first order kinetics equation, and also it was controlled by both the diffusion of the metal complex in the membrane and the chemical reaction at the interface of the boundary layers. The transport flux (J 0) was inversely proportional to the membrane thickness, however, the transport stability improved as the membrane thickness increased. The transport flux of In(III) and Cu(II) was decreased by excessive acidity of feed phase and high concentration of Cl–. The selectivity separation coefficient of In(III)/Cu(II) was up to 34.33 when the original concentration of both In(III) and Cu(II) was 80 mg∙L–1 as well as the pH of the feed phase and the concentration of Cl– in the adjusting context were0.6 and 0.5 mol∙L–1, respectively.Within the range of pH = 1–3, the separation selectivity of In(III)/Cu(II) reached the peak in the case when the Cl– concentration was 0.7 mol∙L–1.

Optimizing Emulsion Liquid Membrane Process for Extraction of Nickel from Wastewater Using Taguchi Method

Abstract--The main objectives of this research were focused on extracting nickel ions from waste water using emulsion liquid membrane as well as determining the optimal conditions for the extraction process. Taguchi experimental design method was applied to determine the optimum extraction conditions. The controllable factors of the emulsion liquid membrane process were carrier; surfactant; and internal phase concentration, treating ratio, stirring time, and feed phase acidity were optimized. The contribution of each controllable factor was also explored. The results indicated the greatest effect of the carrier concentration in comparison to other parameters. The five other parameters slightly affected the extraction percentage of nickel. The optimum conditions for the extraction was found to be carrier concentration (M) of 0.25, surfactant concentration (v %) of 10, internal phase concentration (M) of 0.1, external / emulsion ratio (v/v) of 5, stirring time (min.) of 1, and feed phase pH of 0.5.

Preparation of polymer inclusion membrane including mixture of D2EHPA and Cyanex272 for the extraction of Eu from nitrate media

A polyvinyl chloride (PVC)-based polymer inclusion membrane (PIM) containing mixture of D2EHPA and Cyanex272 as the extractant and polyoxyethylene alkyl ether (POE) as the plasticizer shows potential for the transport of Europium from nitrate media. The synergistic effect of these extractants intensified Eu transport through PIM. The effects of extractant and plasticizer concentration in the membrane, feed phase pH, stripping agent concentration, and membrane thickness were investigated. Up to 97.5% of Eu was extracted using a PIM consisting of 35.16 wt% (D2EHPA + Cyanex272), 18.52 wt% POE and 46.31 wt% PVC. An almost complete back-extraction of the Eu extracted from this membrane was achieved using 1M HNO3 as a stripping phase. The prepared PIM showed good stability for transport of Eu.

Separation of Cu2+, Cd2+ and Cr3+ in a Mixture Solution Using a Novel Carrier Poly(Methyl Thiazoleethyl Eugenoxy Acetate) with BLM (Bulk Liquid Membrane)

The separation process using a novel carrier polyeugenol has active groups N and S has been done with the technique BLM. Polyeugenol has groups active N and S was synthesized from eugenol which is then polymerized into polyeugenol. This polymeric compounds was then acidified become acidic poly (eugenoksi acetate). After the acid formed, then the synthesis was continued by add 4-methyl-5-tiazoleetanol to form esters poly (methyl thiazole eugenoxy ethyl acetate) (PMTEEA). The result of the synthesis was analyzed by FTIR and 1H NMR. This polyester product synthesis was applied as a carrier for separating metal ions Cu2+, Cd2+ and Cr3+ with variations in feed phase pH = 5 and pH = 7 in the membrane of chloroform using techniques BLM. Receiving phase after 24 hours was analyzed by AAS. In variations of feed pH = 5 ions was obtained 66.21% Cd2+, 28.83% Cu2+ and 10.92% of Cr3+, at pH = 7 was obtained 70.77% Cd2+, 30.14% Cu2+, and 3.72% of Cr3+.

Novel amine modification of ZIF-8 for improving simultaneous removal of cationic dyes from aqueous solutions using supported liquid membrane

Effect of amine modification of ZIF-8 on pertraction of mixed Rhodamine B (RhB) and Methylene blue (MB) cationic dye in aqueous solution was studied using flat sheet supported liquid membrane (SLM). Mixtures of mono-(2-etylhexyl) ester of phosphoric acid (M2EHPA), bis-(2-etylhexyl) ester of phosphoric acid (D2EHPA) and nanoparticles were used as carrier and Sesame oil as diluent. Microporous hydrophobic PTFE membrane was used as support for liquid membrane, and strip phase was acetic acid. It was found that loading of amine modified ZIF-8 nanoparticles in carrier, increases the dyes pertraction efficiency more than the pristine ZIF-8 nanoparticles and the optimum loading was obtained as 2000mgL−1.Response surface methodology (RSM) based on Box-Benken design (BBD) with optimum amine modified ZIF-8 nanoparticles loading was used to design the experiments and analyze the effects of three major operating parameters including feed concentration, carrier concentration and initial feed phase pH. The optimum pertraction efficiency for MB and RhB were found as 88.3 and 99.1% respectively and obtained after 10h in feed concentration of 100mgL−1, carrier concentration of 35 vol.% and initial feed phase pH of 6.

Pertraction of l-lysine by supported liquid membrane using D2EHPA/M2EHPA

In this paper, an experimental study regarding pertraction of l-lysine monohydrate (l-lys) was investigated in an aqueous medium through a flat sheet supported liquid membrane (SLM) using a mixture of mono-(2-etylhexyl) ester of phosphoric acid (M2EHPA) and bis-(2-etylhexyl) ester of phosphoric acid (D2EHPA) as carriers and kerosene as diluent. Microporous hydrophobic PTFE membrane was used as support for the liquid membrane, and the strip phase was hydrochloric acid. The parameters affecting pertraction of l-lys, such as feed concentration, carrier concentration, initial feed pH, and stripper concentration were analyzed. It was found that these parameters strongly influence pertraction efficiency. Optimal experimental conditions for l-lys pertraction (pertraction efficiency of 33.4%) were obtained after a 4h separation with l-lys feed concentration of 150ppm, carrier concentration in the membrane phase of 35vol.%, initial feed phase pH of 3, and hydrochloric acid concentration in the strip phase of 1M. Stability of the SLM system was also studied. According to the stability experiments, it was observed that reduction of pertraction efficiency after 8h is less than 6.8%.