Supported Liquid Membrane System Research Articles

Continuous Transport of Zn(II) by Ammonium Chloride Media via Supported Liquid Membrane System

AbstractWith the gradual depletion of traditional zinc resources, the full use of various non‐traditional zinc‐containing resources has received intensive attention. However, the efficient recovery of zinc ions with low concentrations remains challenging. Here efficient and continuous recovery of zinc ions in ammoniacal chloride media by a flat supported liquid membrane system is achieved, using Cyanex923 and TBP mixed extractant as the membrane phase. This article discusses the synergistic effect between Aliquat336, Cyanex923 and TBP, the effects of feed pH, total ammonia concentration, Cl− concentration and temperature on Zn(II) transport.

Chromium (III) Ions Were Extracted from Wastewater Effluent Using a Synergistic Green Membrane with a BinaryCombination of D2EHPA and Kerosene

This study used a supported liquid membrane system (SLM) using Celgard 2400 polypropylene as the support, di(2-ethylhexyl) phosphoric acid (D2EHPA) as the carrier, and kerosene as the diluent. To obtain the best carrier concentration, D2EHPA concentrations between 0.04 and 0.6 M were used. The Cr (III) solutions used in the feed phase had various ionic strengths and were adjusted with NaCl at concentrations ranging from 0.25 to 1.75 M. To maintain a constant pH (4) in the feed phase, a 0.2 M acetic acid–sodium acetate buffer was utilized. Because the rate of Cr (III)-carrier complex formation at the interface of the feed solution and membrane increased up to 20 × 10−4 mol/L, it was discovered that transport of Cr (III) rose with an increase in chromium content in the feeding phase. For the optimization of the various stripping agents, HCl concentration was employed, from 0.25 M to 1.75 M. It was observed that Cr (III) transport increased with the increase in HCl concentration because the transport was at a pH gradient, which was the main driving force. Because of the fact that at the feed phase-membrane contact, D2EHPA combined with chromium ions to form the Cr (III)-carrier complex and released H+ protons, in the feed phase, the Cr (III)-carrier complex was diffused into a stripping phase, wherein Cr (III) ions were stripped and the carrier was reversibly protonated again.

Mathematical Modeling of Extraction of Neodymium using Pseudo-emulsion based Hollow Fiber Strip Dispersion (PEHFSD)

Pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) is a promising alternative technique due to its stability, simplicity and cost of operation. This is an efficient process due to its high surface area for extraction as well as stripping, and low energy consumption for creating the pseudo-emulsion and for the separation of phases. This technique takes the combine advantages of emulsion liquid membrane and overcomes the sufferings of membrane stability in the supported liquid membrane systems. Present work includes extraction of neodymium (III) (Nd) by using TODGA and HNO3 as the extractant cum strippant in PEHFSD technique. A model is developed to study the transport of Nd under different hydrodynamic and chemical conditions that includes organic ratio (A/O) in dispersion, effect of speed of impeller on drop size formation, effect of feed acidity, effect of carrier concentration, effect of feed flow rate. A code is written to solve the model equations numerically to predict the concentration of the feed reservoir with time. Experiments are conducted to obtain the best optimum extraction conditions. Results obtained from the numerical simulations are validated with the experimental data and found a good agreement between them.

Removal of mercury(II) by tri n-butyl phosphate based supported liquid membrane

ABSTRACT. Mercury even at a trace level poses a significant threat to the environment and the ecosystem. Thus, prompting the need to develop a technology to separate mercury(II) selectively from aqueous solutions. The removal of mercury(II) from aqueous solutions using tri n-butyl phosphate (TBP) based supported liquid membrane (SLM) was investigated in this study. HCl and NaOH were used as feed and strip phases, respectively. Factors considered for designing the experiments using the Taguchi method include feed phase acid concentration, strip phase alkali concentration, carrier concentration and initial feed phase mercury(II) concentration. The results indicated that carrier concentration was the most influential factor on the removal efficiency. The percentage contribution of each factor was calculated. The results show that carrier concentration and initial feed phase mercury(II) concentration have a maximum contribution. For the maximum removal of 91.7% of mercury(II) (initial concentration - 10 mg/L) in the feed phase, the optimum conditions were 0.3 M of HCl, 0.2 M of NaOH, and 90% of TBP. SEM analysis was performed to evidence the transportation process through the membrane. The research study indicated the potential use of TBP as a carrier in the SLM system for the selective separation of mercury in trace concentration.
 
 KEY WORDS: Removal of mercury(II), Tri n-butyl phosphate, Taguchi method, Supported liquid membrane
 
 Bull. Chem. Soc. Ethiop. 2021, 35(2), 273-286.
 DOI: https://dx.doi.org/10.4314/bcse.v35i2.5

Liquid-Liquid Extraction of Indium(III) from the HCl Medium by Ionic Liquid A327H+Cl- and Its Use in a Supported Liquid Membrane System.

Ionic liquid A327H+Cl− was generated by reaction of tertiary amine A327 and HCl, and the liquid-liquid extraction of indium(III) from the HCl medium by this ionic liquid dissolved in Solvesso 100 was investigated. The extraction reaction is exothermic. The numerical analysis of indium distribution data suggests the formation of A327H+InCl4− in the organic phase. The results derived from indium(III) extraction have been implemented in a supported liquid membrane system. The influence of the stirring speed (600–1200 min−1), carrier concentration (2.5–20% v/v) in the membrane phase, and indium concentration (0.01–0.2 g/L) in the feed phase on metal transport have been investigated.

Highly selective transport of lithium across a supported liquid membrane

Lithium extraction is a major concern in view of the increase in battery manufacturing. Separation of lithium from associated sodium is still a challenging task due to the similar chemical behavior of these alkali metals. Lithium sources such as salt brines or seawater usually contain large amounts of sodium which requires a high selectivity for the lithium extraction process. In this study, we demonstrate the application of a supported liquid membrane (SLM) with very high selectivity for the separation of lithium from sodium. A synergistic extraction system made of heptafluoro-dimethyloctanedione (HFDOD) and tri-n-octylphosphine oxide (TOPO) ligands diluted in dodecane was selected based on its extraction efficiency (>99 % of lithium extracted) and selectivity for lithium over sodium (separation factor ca.400). Several experimental parameters were studied using a SLM made of HFDOD and TOPO (initial lithium concentration and sodium to lithium concentration ratio in the feed aqueous phase, HFDOD: TOPO ratio in the organic phase). It was found that high lithium permeation rates can be obtained even for low lithium concentrations and high sodium concentration. Membrane stability was evaluated and found to be poor, i.e. significant loss of performances was observed after one cycle of use, due to the leakage of the organic phase and change in HFDOD: TOPO ratio into it. The SLM system designed is suitable for the extraction of lithium from lowly concentrated solutions such as brines and seawater.

Optimizing of malachite green extraction from aqueous solutions using hydrophilic and hydrophobic nanoparticles

Abstract In this study, malachite green (MG) dye extraction was investigated using the supported liquid membrane (SLM) from the aqueous solution. Response surface methodology (RSM) based on the central composite design (CCD) was performed for determining the optimum of operating parameters include pH, feed concentration, and carrier. Extraction percentage of MG after 10 h in optimum condition, feed phase pH of 6, feed concentration of 135.1 mg/ml, and carrier of 21.91%v/v is 93.15%. Influence of presence hydrophilic TiO2 and hydrophobic SiO2 nanoparticles were investigated on extraction percentage and stability of the system. The hydrophilic TiO2 nanoparticles have a negative effect on the SLM and decreased extraction percentage of MG dye and stability of the SLM. The SiO2 hydrophobic nanoparticle caused to improved stability of the SLM system and increased the MG dye extraction percentage. Under optimal operating conditions, loading of the SiO2 hydrophobic nanoparticles to 5 mg/ml, the stability of the system, and MG dye extraction efficiency were obtained 99.07% and 70 h, respectively.

Supported liquid membrane for acetic acid extraction: Screening of membrane support preparation factors

It is essential to remove acetic acid from the biomass hydrolysate during the biorefinery process. The product yield can be effected by the acetic acid due to it inhibition to the microorganism used during the fermentation. Supported liquid membrane (SLM) can be used to remove the acetic acid. The membrane support plays important role in the SLM process. However, due to the use of the commercial membrane support, lack of studied was conducted on the fabrication of custom made membrane support for the SLM process. In the current study, two level full factorial design was employed to screen three fabrication factors during preparation of polyethersulfone-graphene membrane support via vapor induced phase separation technique. The factors screened were temperature of water bath (A) (30-60 °C), exposure time (B) (10-60 s) and air humidity (C) (70-90 RH%). The response was evaluated based on the extraction percentage of the acetic acid from 10 g/L aqueous acetic acid feed solution. All three main factors were significant to the SLM performance. Air humidity factor (C) gave the highest contribution of 28.96% among the main factors. In term of the interaction between factors, water bath temperature (A) and exposure time (B) give the most significant effect with 45.01% percentage of contribution. The highest extraction percentage of the acetic acid using SLM system was 75.95% using the membrane prepare at 30 °C water bath temperature, 10 s exposure time and 70% air humidity.

Study on stripping phase conditions on the levulinic acid extraction using supported liquid membrane

Supported liquid membrane (SLM) is the most effective technique to extract and recover the desired product from the biomass products in a single step. The study of the operation parameters in SLM system is very important to improve the yield of extraction and recovery of the product. In this study, different types of stripping agents such as sodium hydroxide (NaOH), sodium carbonate, hydrochloric acid, trimethylamine, and water were tested in the SLM system to extract levulinic acid (LA). By using 0.3 M trioctylamine in 2-ethyl-1-hexanol as liquid membrane phase, it was found that NaOH was the best stripping agent to extract LA. The concentration of the NaOH stripping agent was varied from 0.25 M to 1 M. The best stripping agent concentration was 0.5 M, which gave an LA extraction of 86% from a 10 g/L LA aqueous solution. The flow rate of the feed and stripping phase was investigated from 25 mL/min to 125 mL/min. SLM operated at 75 L/min was found to be adequate in reducing the boundary layer thickness at both sides of the SLM phases without any leakage of the liquid membrane and breakage of the matrix support. At the best stripping condition, 89% of the LA was extracted using 0.5 M NaOH that operated at flow rate of 75 mL/min.

Comparative study of solvent extraction and supported liquid membrane for the extraction of gallium (III) from chloride solution using organophosphorus acids as extractants

ABSTRACT The transport of Ga(III) from chloride solution by supported liquid membrane (SLM) using organophosphorus acids as carriers was studied and compared with solvent extraction results. The diffusion coefficient, permeability coefficient and mass transfer resistance for both processes were analyzed by investigating various parameters, such as flow pattern, flow rate, pH, Ga(III)/extractant concentration and temperature. Under optimized conditions, the extraction percentage of 97.0% and permeability coefficient of 9.22 × 10−6 m/s was achieved for SLM process. Kinetic modeling was proposed to determine the mass diffusion coefficient of Ga(III) complex across the membrane and stability of this SLM system was also examined.

Removal of heavy metals from leaching effluents of sewage sludge via supported liquid membranes

Heavy metal content of sewage sludge is one of the factors preventing its agricultural use. Leaching processes have been used to solubilize heavy metals and thus reduce metal content of the sludge through chemical or biological routes. Subsequent to leaching processes, metal removal from the supernatant is attractive in terms of decreasing metal content of the effluent and recovering metals. This paper investigates application of supported liquid membrane (SLM) technology for metal removal from leaching effluents. SLM system was first optimized using synthetic metal mixtures. Optimized system was then used for the anaerobic bioleaching and chemical leaching effluents and metal removal efficiencies of 27.1 ± 1.3% and 46.0 ± 4.3% were obtained, respectively. Considering integrated leaching and membrane separation processes, metal removal efficiencies obtained in this study are valuable as it will decrease the metal content of sludge and increase the metal solubilization during leaching process. Future integration of metal leaching and removal technologies would make it possible to develop a sustainable system involving heavy metal removal from sewage sludge, land application of the sludge with a low metal content, and metal recovery.

Simple Preparation of LaPO4:Ce, Tb Phosphors by an Ionic-Liquid-Driven Supported Liquid Membrane System.

In this work, LaPO4:Ce, Tb phosphors were prepared by firing a LaPO4:Ce, Tb precipitate using an ionic-liquid-driven supported liquid membrane system. The entire system consisted of three parts: a mixed rare earth ion supply phase, a phosphate supply phase, and an ionic-liquid-driven supporting liquid membrane phase. This method showed the advantages of a high flux, high efficiency, and more controllable reaction process. The release rate of PO43− from the liquid film under different types of ionic liquid, the ratio of the rare earth ions in the precursor mixture, and the structure, morphology, and photoluminescence properties of LaPO4:Ce, Tb were investigated by inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, Raman spectra, scanning electron microscopy, and photoluminescence emission spectra methods. The results showed that a pure phase of lanthanum orthophosphate with a monoclinic structure can be formed. Due to differences in the anions in the rare earth supply phase, the prepared phosphors showed micro-spherical (when using rare earth sulfate as the raw material) and nanoscale stone-shape (when using rare earth nitrate as the raw material) morphologies. Moreover, the phosphors prepared by this method had good luminescent properties, reaching a maximum emission intensity under 277 nm excitation with a predominant green emission at 543 nm which corresponded to the 5D4-7F5 transition of Tb3+.

Non-dispersive selective extraction of germanium from fly ash leachates using membrane-based processes

ABSTRACTNon-dispersive selective extraction of Ge(IV) tartrates was carried out from simulated fly ash solutions containing heavy metals through supported liquid membranes (SLM). The optimum transport was obtained using a PTFE membrane containing Alamine 336 5%v/v in the condition of tartaric acid 2.76 mmol/L and HCl 1 mol/L in feed and strip phases, respectively. Under this condition, a hollow fiber (HF) SLM experiment was conducted. The results showed that this system could transport germanium from the feed to the strip phase so much faster than the flat sheet (FS) SLM system. The rate of transport through HFSLMs is comparable to dispersive extractions.Abbreviation: A: Effective area of the membrane (cm2); BDL: Below detection limit; Cf,: Feed concentration (mg/L); Ct,: Initial concentration (mg/L); D: Distribution coefficient; ELM: Emulasion liquid membranes; FSSLM: Flat sheet supported liquid membrane; HF: Hollow fiber; LLX: Liquid-liquid extraction; P: Permeation coefficient (m/h); PTFE: Poly tetra fluoro ethylene; PVDF: Polyvinylidene difluoride; T: Tartrate species (C4H4O6); T: Temperature (K); %T:Germanium transport effeciency; V: Volume of feed solution (cm3); t: time (h); η: Viscosity (P.s (c.P)); κ: Boltzmann constant; r: Ionic radius of species; τ: Tortuosity of the membrane; ρ: Porosity; α: Separation factor.

Design of a Hollow Fiber Supported Liquid Membrane System for Zn Speciation in Natural Waters.

A supported liquid membrane-hollow fiber system (HFSLM) has been developed to determine zinc speciation in aquatic environments. The liquid membrane consisted of an organic solution of bis-(2-ethylhexyl)phosphoric acid (D2EHPA) impregnated in the microporous of a polypropylene hollow fiber. The membrane contacted both the donor solution, that contained the metal and the stripping solution, placed in the lumen of the hollow fiber, where the metal was preconcentrated. Different parameters affecting the Zn2+ transport efficiency have been evaluated such as the composition of both the donor and stripping solutions as well as the membrane phase. Extraction and transport efficiencies of free Zn(II) higher than 90% were obtained with a liquid membrane consisting of a 0.1 M D2EHPA solution in dodecane and a 0.1 M HNO3 solution as the stripping phase. The developed HFSLM was used to study the effect of different ligands (EDTA and citric acid) in the donor phase of Zn(II) transport and to investigate the selectivity of the membrane towards Zn when other metals were also present. Finally, the HFSLM system was successfully applied to estimate the free Zn(II) concentrations in three water samples from a mining area. Moreover, the HFSLM system facilitates the analytical determination of trace Zn(II) levels allowing the achievement of enrichment factors of around 700 in the stripping phase.

Intensification of gadolinium(III) separation by effective utilization of nanoliquids in supported liquid membrane using Aliquat 336 as carrier

A supported nanoliquid membrane was developed to improve the separation of rare metal ion gadolinium (Gd) from nitrate solution medium. The nanoliquid membrane was prepared by dispersion of nanoparticles in organic phase and Aliquat 336 was applied as the carrier. TiO2 and SiO2 as hydrophobic and hydrophilic nanoparticles were effectively incorporated in the supported liquid membrane (SLM) system and the effect of size, concentration, and type of nanoparticle in the SLM were evaluated. A membrane phase of 0.015 M Aliquat-336 in kerosene and 0.04 wt% of SiO2 with the size of 15 nm was found to have the highest permeability coefficient of 12.57 × 10−5 m/s and enhanced the permeability coefficient by 28.2%. Hydrophobicity and hydrophilicity of the nanoparticles were observed to have remarkable effects on the permeation of the SLM system and concluded that the hydrophobic nanoparticle was more desirable. Results showed that the solid supported pore’s blockage and aggregation of nanoparticles could bring adverse effects at a high nanoparticle concentration at this SLM configuration. The stability tests were conducted over ten cycles of separation and the supported nanoliquid membrane had slight reduction of permeation during the test.

Enhancing the separation performance of vanadium from a black shale leaching solution by supported liquid membrane using trialkylamine

To enhance the separation efficiency of vanadium from impurities, the highly selective separation of vanadium from multiple impurities and the transport mechanism of vanadium from a black shale leaching-solution, by a supported liquid membrane (SLM) using trialkylamine (N235) as the carrier, were investigated. The effects of parameters such as feed-solution pH, carrier concentration, stripping-solution species, and diluent nature were studied. The separation performance of the SLM system for vanadium from the main impurities in the black shale acid leaching-solution—Fe, Al, P, Si, K, and Mg—was also discussed. The diffusion parameters and facilitated transport mechanism were evaluated using a first-order kinetic model. By enhancing the mass transfer of vanadium and the competitive extraction between vanadium and the impurity ions, the performance of the SLM system for the separation of vanadium from the highly impure black shale leaching-solution was significantly improved. These results show that highly selective separation of vanadium from impurities can be achieved using the N235-SLM system, indicating promising prospects for application in the vanadium industry.

Applicability of a Supported Liquid Membrane in the Enrichment and Determination of Cadmium from Complex Aqueous Samples.

A supported liquid membrane is developed for the separation of Cd from either high in salinity or acidity aqueous media. The membrane consisted of a durapore (polyvinylidene difluoride) polymeric support impregnated with a 0.5 M Aliquat 336 solution in decaline. The effect of carrier concentration, organic solvent and feed and receiving solutions on the metal permeability is studied. This system allows the effective transport of trace levels of Cd through the formation of CdCl42−, which is the predominant species responsible for the extraction process, in both NaCl and HCl solutions. The supported liquid membrane system in a hollow fibre configuration allows the enrichment and separation of trace levels of Cd from spiked seawater samples, facilitating the analytical determination of this toxic metal.

Extraction of Glucose by Supported Liquid Membrane using Polyethersulfone Flat Sheet Membrane Support

Sugar is released during biomass hydrolysis together with unwanted inhibitory compounds such as acetic acid, furfural and hydromethylfurfural. The extraction of particular sugar prior to fermentation process is needed in order to increase the yield of biofuel generated from biomass resources. In the current study, glucose was extracted from the aqueous solution using supported liquid membrane (SLM) system. Polyethersulfone (PES) flat sheet membrane support was fabricated using 15 wt.% PES, 42.5 wt.% DMAc and 42.5 wt.% PEG 200. Liquid membrane was formulated using 2-ethyl hexanol and methyl cholate as solvent and carrier, respectively. The effect of several parameters involved in SLM system such as type of diluent and flowrate of feed and stripping phase on the extraction performance of glucose were studied. About 52.77% of glucose was successfully extracted from aqueous solution using SLM system with 0.01M of methyl cholate in 2-ethyl hexanol. Using simulated biomass hydrolysate solution, almost 54.55% of glucose and 51.08% of xylose were successfully extracted using the SLM system.

Enhancing the stability of supported liquid membrane in phenols removal process by hydrophobic modification

Supported liquid membrane (SLM) has received great attention in recent years. However, very few SLM system could be amplified from the lab to large-scale applications due to insufficient membrane stability. In the present work, a facile surface modification tactic that focused on improving the hydrophobicity of polypropylene hollow fiber membrane (PP-HFM), the support of SLM, by grafting heptadecafluoro-1,1,2,2-tetradecyltrimethoxysilane (FAS) and SiO2 was studied. The influence of hydrophobic modification on the stability of SLM was investigated. The PP-HFM was characterized by SEM, ATR-FTIR and contact angle to test the effects of modification. The analysis results revealed the changes in the surface morphology, chemical composition and hydrophobicity of the membrane. Under optimum modified conditions (0.03mol/L FAS and 0.15% SiO2), the contact angle increased greatly from 92.1° to 132.2° after modification. Therefore, the SLM with modified PP-HFM as the support showed significant enhancement in stability. The average phenol removal percentage could be maintained at 75.32% in 16days of continuous pilot-scale experiments.

Facilitated Transport of Cd(II) Through Supported Liquid Membrane with Tridodecylamine as Carrier

This work investigates the extraction of cadmium (II) from aqueous solution through supported liquid membrane system (SLM). A microporous polypropylene (Celgard 2400) film with tridodecylamine (TDDA) in xylene was used as a membrane phase. Cadmium chloride and hydrochloric acid was used as a feed phase, while ammonia solution was used as stripping reagent. Effect of concentrations of feed, strip solution, and carrier was investigated for the extraction of cadmium. The optimized concentration of Cd(II) and hydrochloric acid, carrier, and striping reagent solution were 1.33 × 10−3 mol/L, 1 mol/L, 30%, and 6 mol/L, respectively. Ninety-two percent extraction of cadmium (II) was achieved under the optimized conditions. In this work, tridodecylamine has been used as a carrier for the first time for the extraction of cadmium ions from wastewater.