Flat Sheet Supported Liquid Membrane Research Articles

Indium extraction from nitrate medium using Cyphos ionic liquid 104 and its mathematical modeling.

The treatment and recovery of pollutants in aquatic system is one of the greatest challenges for environmentalists throughout the world. In this study, solvent extraction of indium using phosphonium ionic liquid (Cyphos IL 104) as an extractant and its mathematical model was proposed for prediction of In(III) ion transport across a FSSLM (flat-sheet-supported liquid membrane). Solvent extraction experiments on indium have been carried out under various experimental conditions in order to assert some fundamental parameters using mathematical analysis for mass transfer process. Diffusion is the process which facilitates metal ion transport across liquid membrane, indicating the applicability of Fick's law of diffusion in model formulation. The influence of different parameters like composition of diluent, feed acidity, and ligand concentration on In(III) ion transport rate has been reported. At different extractant concentrations, the modeling outputs and experimental indium extraction were observed to be in reasonably good agreement.

Separation of Neodymium (III) and Lanthanum (III) via a Flat Sheet-Supported Liquid Membrane with Different Extractant-Acid Systems.

The increasing demand for neodymium (Nd) permanent magnets in electric motors has revived research interest of Nd recovery and separation from other rare earth elements (REEs). Typically, Nd/La separation is necessary for Nd recovery from primary ores and secondary resource recycling. This research used a flat sheet-supported liquid membrane (FSSLM) with different extractant-acid systems to extract Nd from a Nd/La mixture. The recovery and separation of Nd/La with 204P-H2SO4, 507P-HCl, and TBP-HNO3 were discussed. The results showed effective Nd recovery and promising Nd/La selectivity could be achieved in the 507P-HCl system, compared to 204P-H2SO4 and TBP-HNO3. The addition of citric acid to the feed solution was effective for pH buffering but did not improve the Nd transport or Nd/La selectivity. Long-term stability of the 507P-HCl extractant system was demonstrated by extending the processing time from 6 h to 6 days.

A simulation study of an electro-membrane extraction for enhancement of the ion transport via tailoring the electrostatic properties

Membrane technology with advantages such as reduced energy consumption due to no phase change, low volume and high mass transfer, high separation efficiency for solution solutions, straightforward design of membranes, and ease of use on industrial scales are different from other separation methods. There are various methods such as liquid–liquid extraction, adsorption, precipitation, and membrane processes to separate contaminants from an aqueous solution. The liquid membrane technique provides a practical and straightforward separation method for metal ions as an advanced solvent extraction technique. Stabilized liquid membranes require less solvent consumption, lower cost, and more effortless mass transfer due to their thinner thickness than other liquid membrane techniques. The influence of the electrostatic properties, derived from the electrical field, on the ionic transport rate and extraction recovery, in flat sheet supported liquid membrane (FSLM) and electro flat sheet supported liquid membrane (EFSLM) were numerically investigated. Both FSLM and EFSLM modes of operation, in terms of implementing electrostatic, were considered. Through adopting a numerical approach, Poisson-Nernst-Planck, and Navier–Stokes equations were solved at unsteady-state conditions by considering different values of permittivity, diffusivity, and viscosity for the presence of electrical force and stirrer, respectively. The most important result of this study is that under similar conditions, by increasing the applied voltage, the extraction recovery increased. For instance, at EFSLM mode, by increasing the applied voltage from 10 to 30 {text{V}}, the extraction recovery increased from 53 to 98%. Furthermore, it was also observed that the presence of nanoparticles has significant effects on the performance of the SLM system.

Liquid–Liquid Extraction and Supported Liquid Membrane Transport of Neptunium(IV) Across a Flat-Sheet Supported Liquid Membrane Containing a TREN-DGA Derivative

ABSTRACT Liquid–liquid extraction and liquid membrane transport behavior of tetravalent actinide ions viz. Th(IV), Np(IV), and Pu(IV) were investigated for the first time using a diglycolamide (DGA) based dendrimer with a tris(2-aminoethyl)amine (TREN) scaffold as the organic extractant. The generation of 1 dendrimer with six DGA pendent moieties (termed as TREN-G1-DenDGA) extracted Np(IV) more effectively than the other two ions, the trend being Np(IV) > Pu(IV) > Th(IV). The extraction studies of Np(IV) from 3 M HNO3 indicated a 1:1 (metal:ligand) species and the extraction efficiency increased with increasing nitric acid concentration (1–6 M). The transport efficiency of Np(IV) increased with the nitric acid concentration (1–6 M) as well as with the ligand concentration. A very low concentration of 5.75 × 10−4 M ligand, when used as the carrier, resulted in the transport of ca. 25% metal ion transport in 5 h, which increased to >85% with 4.4 × 10−3 M ligand. The transport efficiency of the metal ion across the SLM followed the trend Np(IV) > Th(IV) > Pu(IV). The membrane stability was not satisfactory as seen over a period of 5 days suggesting long-term use may require regular replenishment of the carrier solvent. The effective diffusion coefficient (D eff) of Np(IV)-TREN-G1-DenDGA were determined by the lag-time method and was found to be 5.1 × 10−8 cm2/s.

Recycling of Lithium‐Ion Batteries – Modeling Using Flat Sheet Supported Liquid Membranes

AbstractTo meet the world climate goals, sustainable and efficient technologies will be required. Lithium‐ion batteries (LIBs) emerge as state‐of‐the‐art power sources for all modern consumer electronic devices. This way, the recovery of components plays an important role in the spent LIBs recycling processes. Also, the challenge of research and development of industries is to develop a high number of valuables using the minimum number of experiments, providing low‐cost processes. Two models to be employed in flat sheet supported liquid membranes (FSSLMs) to estimate the behavior of ion concentrations during operation are proposed. Applying the simplified model it is possible to predict the behavior of the system, based on few experiments. This advance can be exciting in industry, such as in the lithium recovery from LIBs using membranes.

Prediction of Nickel Removal using Diffusion Model in Flat Sheet Supported Liquid Membrane

Supported liquid membrane (SLM) is one of the potential extraction methods for the treatment of wastewater containing various toxic heavy metal ions. Advantageously, this process offers simultaneous removal and recovery, as well as low energy consumption and operational cost. In this study, the prediction of nickel removal was investigated using a diffusion model developed through MATLAB.

Pertraction of Nd(III) and U(VI) Through Flat Sheet Supported Liquid Membrane Containing N, N’-Dimethyl-N, N’-Dioctyl-3-Oxadiglcolamide as Carrier

ABSTRACT In this paper, pertraction of Nd(III) and U(VI) from nitric acid media through a flat-sheet supported liquid membrane (FSSLM) was studied by using a self-made liquid membrane device, respectively, with N, N’-dimethyl-N, N’-dioctyl-3-oxadiglcolamide (DMDODGA) diluted in 40/60 (V/V)% n-octanol/kerosene as the carrier. The effects of various factors, such as the acidity of the feed and stripping phases, neodymium concentration, uranium concentration, DMDODGA concentration are discussed. The optimized conditions for Nd(III) transport were found to be 3 M HNO3 in the feed phase, 0.5 M HNO3 in the stripping phase, 0.48 M DMDODGA in n-octanol/kerosene as the carrier. When the initial concentration of Nd(III) was 1 × 10−4 mol/L, the transport rate of Nd(III) was 86.4(±2.2)%. Compared with Nd(III), the liquid membrane was less effective in the transport of U(VI), the highest transport rate of U(VI) was 57.2 (±2.6)%.

Mathematical Modeling of Facilitated Transport of Eu(III) ion by CMPO in Modified diluents as Extractant

A simplified model has been developed to model the pertraction of Eu(III) through the flat-sheet supported liquid membrane (FSSLM) impregnated with CMPO in modified diluents as extractant. The solvent extraction studies of europium were performed under different experimental conditions and some of solvent extraction (SX) data were taken from literature as required to obtain some basic parameters of mathematical modelling for the mass-transfer process. The metal ion transport through liquid membrane is facilitated by diffusion and formulation of model is, therefore, governed by law of diffusion. Effect of various parameters on transport rate of Eu(III) ion, such as ligand concentration, feed acidity, diluent composition etc., has been predicted.

Germanium transport across supported liquid membrane with Cyanex 923: Mathematical modeling

Abstract A mathematical model was developed to monitor the facilitated transport of germanium(IV) from oxalic acid solutions through a flat sheet supported liquid membrane (FSSLM) containing four trialkylphosphine oxides (Cyanex 923). The FSSLM modeling was based on the extraction constant (Kext) calculated from the liquid−liquid extraction (LLX) modeling. The LLX model presented a reliable calculation of the extraction constant (Kex= 2.057×103 L/mol4). The FSSLM model was solved using Matlab® software according to extraction constant, Fick's law, and diffusional principles. The model predicts the overall mass transfer coefficient (Korg) to be 3.84 cm/s. Using this value, diffusion coefficients (Dm) for various Cyanex 923 concentrations of 0.126, 0.252, 0.378, 0.505, 0.631 and 0.757 mol/L are found to be 8.50×10−4, 4.30×10−4, 1.87×10−4, 5.87×10−5, 2.57×10−5, 2.09×10−5 cm2/s, respectively. The results show that the diffusion rate of the current study is approximately more than that of similar FSSLM systems containing Cyanex 923 used to transport various metals. The modeling values are in good agreement with the experimental data, showing the good reliability of the mathematical model.

Non-Dispersive Extraction of Ge(IV) from Aqueous Solutions by Cyanex 923: Transport and Modeling Studies

Transport process of germanium from an aqueous solution containing oxalic acid and 100 mg/L Ge was studied. Cyanex 923 immobilized in a polytetrafluoroethylene membrane was employed as a carrier in a flat-sheet supported liquid membrane (FSSLM) system. The speciation of the germanium ion in the oxalic acid medium and related diagrams were applied to study the transport of germanium. The effective parameters such as oxalic acid, carrier concentration, and strip reagent composition were evaluated in this study. Based on the experimental data, the oxalic acid and carrier concentrations of 0.075 mol/L and 20% v/v were the condition in which the efficient germanium transport was achieved, respectively. The concentration range of 0.04–0.1 mol/L was selected for sodium hydroxide (NaOH) as a strip reagent providing the best efficiency to transport germanium through the supported liquid membrane (SLM) system. Furthermore, the permeation model was obtained to calculate the mass transfer resistance of the membrane (Δm) and feed (Δf) phases. According to the results, the values of 1 and 1345 s/cm were found for Δm and Δf, respectively.

Improved rare earth elements recovery from fluorescent lamp wastes applying supported liquid membranes to the leaching solutions

Due to the continuously growing demand of rare earths in advanced technologies, end-of-life fluorescent lamps may become feasible rare earth elements (REEs) raw materials, reducing thus their supply risk. Considering acid leaching as the most common method in the metal recover from an end-of-life product real scratch resulting from the fluorescent lamps, this paper proposes an improvement of the REEs recovery from these wastes adding a supported liquid membrane (SLM) step to minimize the loss of these metals in the first leaching (L1). HNO3 or HCl are the most appropriate acid agents in the L1 stage considering the balance between the Ca (II) impurity removal and the REEs losses minimization. These REEs lost can be entirely recovered from the L1 leachate by flat sheet supported liquid membranes (FSSLM) using Cyanex 923 as carrier and Na2EDTA as the receiving phase. REEs, especially Y and Eu, have been recovered in quantitative yields using a L1–FSSLM–L2 process.

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.

Mathematical modeling on non-dispersive extraction of germanium from aqueous solutions using Aliquat 336.

In this work, the mathematical modeling of the facilitated transport of germanium (non-dispersive extraction) through a flat sheet membrane with an Aliquat 336 carrier was described. The flat sheet supported liquid membrane (FSSLM) experiments were performed under conditions germanium ≈ 100 mg/L, tartaric acid concentration of 2.76 mmol/L, and carrier concentrations of 2.5-10%v/v. The extraction equilibrium, mass transfer, and diffusion equations based on Fick's law were the principles of modeling. Modeling was carried out by programming in Matlab mathematical software to obtain the extraction (Kex) and mass transfer constants (Km) as the objective parameters. According to the model resolution, Kex and Km were found to be 0.178 and 9.25 × 10-2 cm/s, respectively. The correlation coefficients between model and experimental data relating to the Aliquat 336 concentrations of 2.5, 5, 7.5, and 10%v/v were found as 0.96, 0.98, 0.99, and 0.92. The parameters of root mean square error, bias, and scatter index showed the model accuracy. In addition, diffusion coefficients relating to Aliquat 336 concentrations of 2.5, 5, 7.5, and 10%v/v were calculated using mass transfer coefficients to be 2.4 × 10-4, 2.23 × 10-4, 1.91 × 10-4, and 1.79 × 10-4 cm2/s, respectively.

Liquid-liquid extraction and facilitated transport of f-elements using an N-pivot tripodal ligand

Diglycolamide (DGA)-functionalized tripodal ligands offer the required nine-coordinated complex for effective binding to a trivalent lanthanide/actinide ion. A N-pivot tripodal ligand (TREN-DGA) containing three DGA pendant arms was evaluated for the extraction and supported liquid membrane transport studies using PTFE flat sheets. Solvent extraction studies indicated preferential extraction of 1:1 (M:L) species, while the metal ion extraction increased with increasing HNO3 concentration conforming to a solvated species extraction. Flat sheet-supported liquid membrane studies, carried out using 4.0 × 10−3 M TREN-DGA in 95% n-dodecane + 5% iso-decanol indicated faster mass transport for Eu3+ ion as compared to Am3+ ion. The determined transport parameters indicated slow diffusion of the M-TREN-DGA (M = Am or Eu) complex being the rate-determining step. The transport of lanthanides and actinides followed the trend: Eu3+ > Am3+∼ Pu4+ >> UO22+ and Am can be selectively separated from a mixture of U and Pu by oxidizing the latter to its +6 oxidation state. The liquid membrane stability was not encouraging and was deteriorating the transport efficiency with time, which was attributed to carrier loss into the aqueous phases.

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.

Mathematical modeling for facilitated transport of Ge(IV) through supported liquid membrane containing Alamine 336

A mathematical model was developed for the germanium-facilitated transport from a medium containing tartaric acid using Alamine 336 as a carrier. Modeling was carried out based on the extraction constant (K ext) obtained from the liquid–liquid extraction (LLX) modeling. The LLX data were achieved from experiments with conditions being Alamine 336 concentrations of 0.1–10% v/v from a solution containing about 1.378 mmol/L Ge (100 mg/L) and tartaric acid as an anionic complexant. The LLX model was attained using the equilibrium-based procedure and fitted to extraction experimental data for various carrier concentrations. This model presented an accurate extraction constant (K ext = 0.02) used in the facilitated transport modeling. The flat sheet supported liquid membrane (FSSLM) experiments were conducted in the condition of 1.378 mmol/L Ge (100 mg/L), tartaric acid concentration of 2.760 mmol/L, 1 M HCl as a stripping phase and various Alamine 336 concentrations in the range of 0–35% v/v. The FSSLM model was developed according to the Fick’s law, the diffusional transport, and equilibrium equations. According to the model, mass transfer and diffusion coefficients for various concentrations of the carrier were found. In addition, the calculated and experimental values had a good correlation with together showing the validity of the model. This model can be used in the further process simulation such as hollow fiber SLMs.

Hollow fiber supported liquid membrane studies using a process compatible solvent containing calix[4]arene-mono-crown-6 for the recovery of radio-cesium from nuclear waste

Abstract Bis-octyloxy-calix[4]arene-mono-crown-6 (CMC) was evaluated for radio-cesium separation from acidic feed solutions using hollow fiber supported liquid membrane (HFSLM) technique. Solvent extraction and flat sheet supported liquid membrane (FSSLM) studies were pursued to optimize the conditions required for the subsequent HFSLM studies. The permeation rate of cesium in HFSLM increased steadily with nitric acid concentration from 1 M HNO 3 to 6 M HNO 3 . At a moderate acidity of 4 M HNO 3 , which is the acid concentration of the high level waste, near quantitative (>99%) transport of cesium was possible within 2 h of operation at 300 mL scale. Transport was suppressed under simulated high level waste conditions due to the presence of large concentrations of cesium (0.32 g/L), but >90% transport was observed in 6 h. Stability of the membrane was excellent as monitored from 12 days of continuous operation. The permeability coefficient, mass transfer coefficient and various diffusional parameters of the diffusing metal/ligand species were calculated to understand the permeation behvaiour of cesium. The present work explored the possible use of CMC in hollow fiber contactor for radioactive waste treatment where the ligand inventory is very low.

Synergistic extraction of Cr(VI) from Ni(II) and Co(II) by flat sheet supported liquid membranes using TIOA and TBP as carriers

Abstract In present study, the synergistic separation of Cr(VI) has been investigated from synthetic acidic solution containing Cr(VI), Co(II) and Ni(II) by fl at sheet supported liquid membrane (FSSLM) technique using triisooctylamine (TIOA) and tri-n-butyl phosphate (TBP) as carriers. The main goal of the study was based in the exploring of the synergistic effect of TBP on selective extraction of Cr(VI) in presence of Co(II) and Ni(II) ions. The various parameters related with membrane and aqueous solution properties were studied to identify the optimum extraction and stripping conditions of the Cr(VI) through FSSLM. In the optimum conditions, initial mass flux (J0) and separation factors (βCr/Co and βCr/Ni) were obtained as 1.49 x 10-05 (kg/m2.s), 382.2 and 725.3 respectively from aqueous H2SO4 media through Celgard 2500 (Celgard Inc., USA) polymer support. As a result, the considerable synergistic infl uence on selective transport of Cr(VI) through FSSLM using TIOA and TBP as carriers has been identifi ed.

A highly efficient solvent system containing chlorinated cobalt dicarbollide in NPOE—Dodecane mixture for effective transport of radio-cesium from acidic wastes

The present paper is a first time report on the pertraction of radio-cesium (137Cs) across a flat sheet supported liquid membrane (FSSLM) containing a solvent system containing chlorinated cobalt dicarbollide (CCD) in a diluent mixture containing 2-nitrophenyloctyl ether (NPOE) and n-dodecane. The feed phase consisted of 1M HNO3 while 8M HNO3 was the receiver phase. The optimized solvent system with 1.0×10−2M CCD in 60% NPOE+40% n-dodecane was found to be highly efficient for the transport of the metal ion in terms of metal ion extraction (87.8%) and stability of the liquid membrane. The transport efficiency decreased with increasing feed phase HNO3 concentration suggesting applicability of the transport system for radioactive wastes at low to moderate acidity (≤1M HNO3). Furthermore, the transport rates of Cs(I) increased with increasing CCD concentration suggesting direct involvement of the carrier molecule in the metal ion transport. The addition of PEG-400 (used for Sr(II) transport) into the solvent system did not result in the expected co-transport of Sr(II) which was attributed to the leaching out of the ligand from the membrane pores due to its high aqueous solubility. The diffusion coefficient was calculated by the lag time method and was found to be 1.7×10−7cm2/s which was somewhat lower than that obtained by Danesi׳s method.

Supported liquid membrane-based simultaneous separation of cadmium and lead from wastewater

This work is aimed at the investigation of simultaneous extraction and recovery of heavy metals (cadmium and lead) from aqueous solutions through a coconut oil-based Flat Sheet Supported Liquid Membrane (FS-SLM). Environmentally benign nature of coconut oil is the prime advantage in this technique. N-Methyl-N,N-dioctyloctan-1-ammonium chloride (Aliquat 336) is an ideal carrier agent for the transportation of the said heavy metals. Ethylenediaminetetraacetic acid (EDTA) was selected as stripping agent keeping in view its metal chelating capacity. Initially, the performance of Supported Liquid Membrane (SLM) was investigated only for the transportation of cadmium, or precisely Cd(II). A porous polymeric solid membrane viz., polyvinylidene fluoride (PVDF) was used as a support in order to hold and contain the membrane liquid in the SLM structure. The size of the pores in the support is 0.2μm. The effects of various operating conditions viz. concentration of the carrier in membrane phase, concentration of stripping agent, pH of feed phase etc. were studied. The optimum process conditions for the transportation of Cd(II) were: 0.5% (v/v) Aliquat 336 in coconut oil as membrane phase, 0.015M EDTA as stripping agent, and pH of 6.5 in the feed phase. The initial feed concentration was 5ppm and the total transportation time was 10h. Transportation of another heavy metal viz., lead (Pb) was also carried out with the above optimum process conditions. Finally, simultaneous transportations of both metals (lead and cadmium) were studied with various molar ratios (Cd:Pb) in the feed. The optimum extraction and recovery of cadmium were found as 79% and 67%, respectively, and that of lead were found as 84% and 78%, respectively, in simultaneous transportation. Lead was observed to be preferentially transported through SLM due to its favorable electronic configuration.