Supported Liquid Membrane Research Articles

New and efficient direct-SLM two-phase hollow fiber electromembrane extraction coupled to GC/MS for the analysis of nitrosamines in different types of sausage: Investigation of meat type, meat percent and cooking methods.

The potent two-phase hollow fiber electromembrane extraction technique coupled to gas chromatography mass spectrometry (HF-EME/GC-MS) was proposed for the determination of six types of carcinogen nitrosamines in sausages samples. Two steps of sample digestion were accomplished for the complete removal of fat globules and efficient release of target analytes. The extraction principle was based on electro-migration of target analytes via specific fiber to extraction solvent. 2-Nitrophenyl octyl ether (NPOE) was dexterously employed as both supported liquid membrane and extraction solvent, which is compatible with GC-MS. After the extraction process, the NPOE containing nitrosamines was directly injected to GC-MS without extra steps requirement to reduce analysis time. The consequences revealed that N-nitrosodiethylamine (NDEA) as the most potent carcinogen has the highest concentration in fried and oven-cooked sausages with 70% of red meat. The meat type and amount and also cooking process could significantly effect on nitrosamines formation.

Environmental Applications of Electromembrane Extraction: A Review.

Electromembrane extraction (EME) is a miniaturized extraction technique that has been widely used in recent years for the analysis and removal of pollutants in the environment. It is based on electrokinetic migration across a supported liquid membrane (SLM) under the influence of an external electrical field between two aqueous compartments. Based on the features of the SLM and the electrical field, EME offers quick extraction, effective sample clean-up, and good selectivity, and limits the amount of organic solvent used per sample to a few microliters. In this paper, the basic devices (membrane materials and types of organic solvents) and influencing factors of EME are first introduced, and the applications of EME in the analysis and removal of environmental inorganic ions and organic pollutants are systematically reviewed. An outlook on the future development of EME for environmental applications is also given.

Separation of Rare-Earth Elements by Supported Liquid Membranes: Impacts of Soluble Iron, Aluminum, and pH in Low-Grade Feedstocks

Separation of Rare-Earth Elements by Supported Liquid Membranes: Impacts of Soluble Iron, Aluminum, and pH in Low-Grade Feedstocks

Highly selective separation of plutonium using a mono-amide-based supported liquid membrane

ABSTRACT A monoamaide-functionalized supported liquid membrane was developed and employed for efficient and selective solid phase separation of Pu(IV). The membrane was prepared in a simple, one-pot process and was characterized for its homogeneity, stability and hydrophobicity. Various membrane parameters like sorption efficiency, sorption kinetics, sorption isotherm and equilibrium uptake capacity were studied for Pu(IV) in nitric acid medium. Langmuir and Freundlich isotherm models were employed for understanding the sorption mechanism of the membrane. Lagergren first-order kinetics and pseudo-second-order kinetics were applied to understand the plutonium sorption kinetics. The equilibrium sorption capacity of the membrane was found to be 27.18 mg g−1and the sorption kinetics followed a pseudo-second-order reaction with rate constants of 1.129 g mg−1 min−1 for Pu(IV). Stripping of Pu from the membrane was also studied to check the regeneration and reusability of the supported liquid membrane. The membrane was found to be very selective toward Pu(IV) in 4 M HNO3 medium, with separation factors 42 and 75 with respect to Am(III) and U(VI), respectively.

Stabilization of [BMIM][PF6] ionic liquid membrane in structurally optimized multilayer ceramic support through aqueous DEA solution for CO2/CH4 separation

The stability of the ceramic supported liquid membranes (SLMs) is one of the most interesting research subjects. In this work, the SLMs’ stability for CO2/CH4 separation was investigated. Following pressing α-Al2O3 substrates at 400, 600, and 800 bar, colloidal and polymeric TiO2 intermediate and top layers were coated. Aqueous diethanolamine (DEA) solution was used as solvent in the SLM to optimize support structure based on CO2/CH4 separation performance. The pressed support at 800 bar and coated with TiO2 demonstrated best performance and selected for further study. Subsequently, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid (IL) was immobilized inside the selected support and used as the supported ionic liquid membrane (SILM) for CO2/CH4 separation. The SILM separation performance was evaluated under different pressures and temperatures. Temperature was found to has greater effect than pressure due to a decrease in IL's viscosity and an increase in penetrant diffusivity. At 25 °C and 1 bar, SILM exhibited consistent and reliable performance as CO2 and CH4 permeabilities of 244.0 and 7.4 Barrer, respectively, and CO2/CH4 selectivity of 33.0 over 6 h. The findings contribute to understanding the implementation of multilayer ceramic SILMs for CO2/CH4 separation and highlight its potential along with opening up new avenues.

On the Biological Applications of Liquid Membranes : A Short Review

Studies on permeation through membranes have attracted attention during the last few decades because of the various applications of membranes in our day today life. Studies on Bulk liquid membranes (BLM). Emulsion liquid membranes (ELM) Supported liquid membranes (SLM) all have led to wonderful applications in technology and biology. An attempt is being made to throw light on the applications these liquid membranes in various biological fields viz facilitated transfer controlled release of drugs and all pharmaceutical applications.

Green strategies using solvent-free biodegradable membranes in microfluidic devices. Liquid phase microextraction and electromembrane extraction

In this work, a novel solvent-free microfluidic method based liquid phase microextraction has been proposed for the first time. A comprehensive study of liquid phase microextraction (LPME) and electromembrane extraction (EME) implemented in microfluidic formats has been carried out to investigate the efficiency of biodegradable membranes (such as agarose) without organic solvent to develop fully environmental microfluidic methods. For this study, non-polar and polar basic compounds (five) were selected as model analytes and different agarose membrane compositions were synthesized and tested with and without organic solvent (solvent-free). Under optimal experimental conditions, the extraction efficiencies obtained using solvent-free LPME-chip devices were similar to the ones obtained using solvent-free EME-chip devices at very low voltages (0.25 V), however, LPME microfluidic format was selected due to its simplicity. The proposed green microfluidic device was successfully applied in urine samples with recoveries between 80 and 93% for all analytes and relative standard deviation below 7% for all analytes. Results were compared with experiments previously conducted using conventional (polypropylene) membranes, observing that solvent-free microfluidic systems based on biodegradable solid support materials have proven to be an attractive alternative and offered the same advantages in terms of membrane stability allowing consecutive extractions compared to supported liquid membranes (SLM) microfluidic methods.

Modelling and Comparative Analysis of Different Methods of Liquid Membrane Separations.

This article is devoted to a brief review of the modelling of liquid membrane separation methods, such as emulsion, supported liquid membranes, film pertraction, and three-phase and multi-phase extraction. Mathematical models and comparative analyses of liquid membrane separations with different flow modes of contacting liquid phases are presented. A comparison of the processes of conventional and liquid membrane separations is carried out under the following assumptions: mass transfer is described by the traditional mass transfer equation; the equilibrium distribution coefficients of a component passing from one of the phases to another are constant. It is shown that, from the point of view of mass transfer driving forces, emulsion and film pertraction liquid membrane methods have advantages over the conventional conjugated extraction stripping method, when the mass-transfer efficiency of the extraction stage is significantly higher than the efficiency of the stripping stage. The comparison of the supported liquid membrane with conjugated extraction stripping showed that when mass-transfer rates on the extraction and stripping sides are different, the liquid membrane method is more efficient, while when they are equal to each other, both processes demonstrate the same results. The advantages and disadvantages of liquid membrane methods are discussed. The main disadvantages of liquid membrane methods-low throughput and complexity-can be overcome by using modified solvent extraction equipment to carry out liquid membrane separations.

Efficient flat membrane based liquid phase microextraction of cathinones from environmental water and biological samples

Cathinone drugs are one kind of new psychoactive substances, which are widely acknowledged to be harmful. Thus, rapid and efficient extraction of cathinone drugs from biological materials is of great importance in the field of forensic medicine and public health. In this work, flat membrane-based liquid phase microextraction (FM-LPME) was applied to extract five cathinone drugs [cathinone (Cath), methcathinone (MCath), 4-methyl-methcathinone (Mephe), ethylcathinone (ECath), and 4-fluoromethcathinone (FMCath)] from spiked environmental water, whole blood and urine samples, respectively. Interestingly, two binary supported liquid membrane (SLM) solvents containing the mixture of 1-ethyl-2-nitrobenzene (ENB) and n-decanol/n-octanol were developed to obtain satisfied recoveries for cathinone drugs. The developed FM-LPME system was optimized with high performance liquid chromatography - ultraviolet (HPLC-UV), and the optimal LPME conditions depended on the sample matrices. Finally, the LPME systems were evaluated by liquid chromatography tandem mass spectrometry (LC-MS/MS) with environmental and biological samples. The limit of detection (LOD) and limit of quantitation (LOQ) of the five cathinone drugs from environmental water and biological samples were in the range of 0.07–0.69 ng/mL and 0.22–2.31 ng/mL, respectively. The linear range of cathinone drugs for environmental water samples (with R2 ≥ 0.9904) and biological samples (with R2 ≥ 0.9910) were 0.5–200 ng/mL. The repeatability and accuracy provided at 5, 50 and 200 ng/mL were 1%-10% (RSD) and 89%-113%, respectively. This work will promote the application of LPME in detection of trace level poisons/pollutants in the field of forensic toxicology analysis and wastewater-based epidemiology in the near future.

Towards clean sustainable yttrium separation strategy using hollow fiber renewal supported liquid membrane with [N1888][CA12

Yttrium (Y) separation from Y-rich heavy rare earth groups is a complex challenge due to their similar physical and chemical properties. Conventional industrial separation processes require the use of complex and polluting techniques, thus highlighting the need for cleaner and more efficient methods for Y separation. In this study, a new method for separating Y from Y-rich heavy rare earth groups was developed using the hollow fiber renewal support liquid membrane (HFRLM) with an amine-group-functionalized ionic liquid ([N1888][CA12]) system, which eliminates the need for acids and bases during the extraction and stripping process. The high extraction efficiency and strong hydrophobicity of [N1888][CA12] enhances the stability and efficacy of the HFRLM. The optimal hydrodynamic conditions were achieved using a stripping solution of water, phase volume ratio of 4.8, NaCl concentration of 0.6 mol/L, [N1888][CA12]concentration of 0.4 mol/L, and flow rate of 350 mL/min. Moreover, a deionized water regeneration [N1888][CA12]-HFRLM method was established, and the system remained highly stable after five regenerations. Furthermore, the [N1888][CA12]-HFRLM system was evaluated for separating Y from Y-rich heavy rare earth groups, and it was found that the molar ratio of Y increased from 70.9% to over 98.4%.

Determination of amphetamine enantiomers in urine by conductive vial electromembrane extraction and ultra-high performance supercritical fluid chromatography tandem mass spectrometry.

Separation and quantification of amphetamine enantiomers are commonly used to distinguish between consumption of prescription amphetamine (mostly S-amphetamine) and illicit forms of the drug (racemate). In this study, electromembrane extraction with prototype conductive vials was combined with ultra-high performance supercritical fluid chromatography (UHPSFC-MS/MS) to quantify R- and S-amphetamine in urine. Amphetamine was extracted from 100 μL urine, diluted with 25 μL internal standard solution and 175 μL 130 mM formic acid, across a supported liquid membrane (SLM) consisting of 9μL of a 1:1(w/w) mixture of 2-nitrophenyloctyl ether (NPOE) and bis(2-ethylhexyl)phosphite (DEHPi) into an acceptor phase containing 300 μL 130 mM formic acid. The extraction was facilitated by the application of 30 V for 15 min. Enantiomeric separation was achieved using UHPSFC-MS/MS with a chiral stationary phase. The calibration range was 50-10,000 ng/mL for each enantiomer. The between-assay CV was ≤5%, within-assay CV ≤ 1.5%, and bias within ±2%. Recoveries were 83%-90% (CV ≤ 6%), and internal standard corrected matrix effects were 99-105 (CV ≤ 2%). The matrix effects ranged from 96% to 98% (CV ≤ 8%) when not corrected by the internal standard. The EME method was compared with a chiral routine method that employed liquid-liquid extraction (LLE) for sample preparation. Assay results were in agreement with the routine method, and the mean deviation between methods was 3%, ranging from -21% to 31%. Finally, sample preparation greenness was assessed using the AGREEprep tool, which resulted in a greenness score of 0.54 for conductive vial EME, opposed to 0.47 for semi-automated 96-well LLE.

Deep eutectic solvent-based electromembrane hollow fiber liquid phase microextraction for determining Pb in water and food samples

In the present work, the determination of Pb using the electromembrane hollow fiber liquid phase microextraction with a deep eutectic solvent and graphite furnace atomic absorption spectrometry detection (DES-EM-HFLPME-GFAAS) was proposed. First, Pb(II) in the sample was converted to the anionic form of Pb-oxyanion under alkali conditions. Then, the electro-assisted technique was applied to facilitate the anion passing through the supported liquid membrane into the phase of deep eutectic solvent mixed with buffer solution. Finally, GFAAS was applied for monitoring the total lead in samples. The important parameters affecting the method efficiency were studied. Under optimized conditions, the linear range was observed in the range 0.036-1.0 ng/mL. The limit of detection and limit of quantitation were 0.011 and 0.036 ng/mL, respectively. Precision as %RSD was obtained from 1.03 to 3.49%. The enrichment factor and the preconcentration factor were 111 and 750, respectively. The proposed method was applied to determine lead in water and food samples (i.e., drinking and tap water, canned food, and vegetables) with acceptable recoveries from 86.70 to 116.0%. The method was successfully applied to determine the amount of lead in the standard reference materials, and the concentrations measured were not significantly different at 95% of confidence level from the certified values.

Hollow-Fiber Liquid-Phase Microextraction (HF-LPME) Coupled On-Line to Liquid Chromatography for the Determination of the Herbicides 2,4-Dichlorophenoxyacetic Acid and 2-Methyl-4-chlorophenoxyacetic Acid and Their Main Metabolites in Soil Samples

The use of hollow-fiber liquid-phase microextraction (HF-LPME) is very promising for the clean-up, enrichment, and analysis of chlorophenoxyacetic acid herbicides and their metabolites from environmental and biological samples. An on-line methodology coupling HF-LPME (using a hydrophobic polypropylene hollow fiber of 57 cm length, 0.3 mm i.d., 0.2 μm pore size, and 75% porosity) and HPLC-UV has been developed for the analysis of these compounds in soil samples taken from environments treated with these herbicides. Di-hexyl ether was found to be the best solvent for the enrichment of the target herbicides. The use of supported liquid membranes has shown a high and efficient clean-up of the dissolved organic matter present in soil extracts. The enrichment factors achieved with the on-line methodology have allowed us to reach the detection limits of 0.1–0.3 µg·kg−1 soil, by analyzing 20 mL of alkaline extract as a donor solution and using 1 mL of stripping solution, which has permitted us to detect and follow the presence of these compounds in soil samples until nine days after the application of the herbicide. The on-line method has been applied in a preliminary study to assess the mobility of the chlorophenoxyacetic acid herbicides through soils. It has also been found that degradation of these compounds in soil is relatively fast and some metabolites were detected in soils just one day after the application of the herbicide. The high enrichment factors obtained with the HF-LPME procedure allow for the obtainment of low detection limits, which permits the use of a simple HPLC detector, such as UV, which simplifies and reduces the cost of analyses.

A Green Method for the Determination of Cadmium in Natural Waters Based on Multi-Fibre Supported Liquid Membranes.

Supported liquid membranes have been used to implement a hollow fibre liquid-phase microextraction (HF-LPME) method for the preconcentration of Cd(II) in natural waters as a sample preparation step for its determination by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS). This system was designed to use four hollow fibres simultaneously with the same sample, thus improving the simplicity, speed and reproducibility of the results. The organic liquid membrane bis-(2,4,4-trimethylpentyl) phosphinic acid (Cyanex® 272) dissolved in dihexylether (DHE) was immobilised into the pores of the walls of polypropylene hollow fibres. After extraction, the cadmium-enriched acidic phases were recovered and analysed by triplicate. To optimise the extraction process, the effect of both physical and chemical variables was studied, and optimum results with an enrichment factor (EF) of 292 were obtained for a fibre length of 6 cm, 1.06 M Cyanex 272, 0.04 M HNO3, stirring rate of 600 rpm and an extraction time of 4.26 h. For practical applications, extraction time was reduced to 2 h, keeping the EF as high as 130. Under these conditions, a detection limit of 0.13 ng L-1 Cd(II) was obtained, with a reproducibility of 3.3 % and a linear range up to 3 µg L-1 being achieved. The proposed method was successfully applied to the determination of cadmium in mineral, tap and seawater samples.

CO2 Separation Using Supported Deep Eutectic Liquid Membranes Based on 1,2-propanediol

In this work, deep eutectic solvents (DESs) composed of choline chloride, acetylcholine chloride or tetrabutylammonium chloride, and 1,2-propanediol were used as a liquid phase for polypropylene-based supported liquid membranes (SLMs) and evaluated for the separation of carbon dioxide from CO2/N2 mixtures. Fourier transform infrared spectra were obtained to confirm DES formation, and the thermal stability of solvents was investigated using thermogravimetric analysis. The physicochemical properties of DESs and carbon dioxide solubility were determined in a temperature range of 293.15–313.15 K. The effects of the hydrogen bond acceptor structure and the acceptor/donor molar ratio in regard to properties and CO2 separation potential were discussed. The permeability of CO2 and N2 in DES-based SLMs was determined, and the ideal CO2/N2 selectivity was calculated. The gas permeation results of the 1,2-propanediol-based DES-based supported liquid membranes showed that the permeability of CO2 varied from 86 to 152 barrers in 293.15 K. Similarly, the ideal CO2/N2 selectivity varied from 21 to 30. The performance of DES–SLMs was compared with the competing imidazolium-based supported ionic liquid membranes and proved DES–SLMs as a promising alternative considering their green potential and comparable gas separation performance.

A green microfluidic method for the simultaneous extraction of polar and non-polar basic compounds in biological samples

Microfluidic devices as sample treatment have showed significant advancements in recent years, becoming an important tool in pharmaceutical analysis. In this work, a green microfluidic method for the simultaneous extraction of basic polar and non-polar compounds is proposed for the first time, offering a new and more sustainable and environmentally friendly alternative. A mixture of camphor:menthol 1:1 is presented as a new green supported liquid membrane (SLM) for the simultaneous extraction of a wide log P range for basic compounds (0.4 < log P < 5): verapamil hydrochloride (VRP), tyramine (TYR), atenolol (ATN), metopropol (MTP) and nortriptyline (NRP). Different SLMs were investigated to offer new other green alternatives for polar or non-polar basic drugs. Microfluidic operational parameters were also optimized at pH 1.5, pH 11.5 and 1 µL min−1 as acceptor phase, donor phase and donor flow rate, respectively. Camphor:menthol 1:1 showed good stability and reproducibility (RSD < 5%) in human urine samples. It was found to be an attractive alternative to traditional toxic organic solvents applied in microextraction techniques. The green microfluidic method offered good recoveries between 50 and 100% for all compounds in urine sample after 7 min extraction, using only 3 µL of Ca:Me 1:1 and showing a good long-term stability system up to 6 consecutive extraction in real samples. A relative standard deviation (n = 3) was below 6 % for all compounds with and without replacing the membrane of the system.

Liquid polymerized ionic liquids for energy storage applications

Supported liquid membranes (SLM) offer promise of improved molecular and ionic transport in polyelectrolyte membranes (PEM), key components in batteries and fuel cells. Incorporation of ionic liquids (IL) into PEM has demonstrated increased molecular and ionic transport, and it is probable that liquid polymerized ionic liquids (LPIL) also will benefit such PEM properties. Herein we demonstrate preparation of LPIL copolymers that have suitable functionality for tethering such LPIL to SLM. We uncover a design principle for producing LPIL, wherein liquid homopolymers that are precursors for PIL are partially modified and converted into LPIL. We show that the homopolymer poly(bromoundecyl acrylate), poly(AcOC11H22Br), is such a liquid precursor. We explore conversion of this homopolymer into LPIL by using it to alkylate 1-methyl imidazole.

Transport of Chromium(VI) across a Supported Liquid Membrane Containing Cyanex 921 or Cyanex 923 Dissolved in Solvesso 100 as Carrier Phase: Estimation of Diffusional Parameters.

An investigation of chromium(VI) transport across a supported liquid membrane containing the phosphine oxides Cyanex 921 and Cyanex 923 dissolved in Solvesso 100 as carrier phases was carried out in batch operation mode. Chromium(VI) transport was investigated as a function of different variables: hydrodynamic conditions in the feed (1000-1600 min-1) and stripping (600-1500 min-1) phases, HCl (0.25-2 M) and indium (0.01-0.1 g/L) concentrations in the feed phase, and carrier (0.01 M-0.75 M) concentration in the membrane phase. Indium was recovered in the stripping phase using hydrazine sulphate solutions, and, at the same time, chromium(VI) was reduced to the less harmful Cr(III) oxidation state. Models describing the transport mechanism comprising a diffusion process through the feed aqueous diffusion layer, fast interfacial chemical reaction, and diffusion of the respective chromium(VI)-phosphine oxide complexes across the membrane were developed. The equations describing the rate of transport correlate the membrane permeability coefficient with diffusion and equilibrium parameters, as well as the chemical compositions of the respective metal-carrier phases. The models were used to calculate diffusional parameters for each metal-carrier system, and the minimum thickness of the feed boundary layer was calculated as 1 × 10-3 cm and 6.3 × 10-4 cm for the Cr(VI)-Cyanex 921 and Cr(VI)-Cyanex 923 systems, respectively.

Facilitated solvent screening for membrane-based extraction of chiral amines via a priori simulations

Chiral amines are important building blocks in the pharmaceutical industry. A challenge for the current industry is their difficult synthesis procedures, which employ harsh operating conditions or have an unfavourable equilibrium constant. An interesting strategy in improving the reaction equilibrium is the use of in-situ product removal via membrane extraction (ME) using supported liquid membranes (SLM), which is explored in this work. More specifically, the separation of the product amines α-methylbenzylamine (MBA) and 1-methyl-3-phenylpropylamine (MPPA) from the donor amine isopropyl amine (IPA) by employing SLMs is investigated in this study. A difficulty in SLM-applications is the solvent selection, which mostly requires the use of extensive liquid–liquid extraction (LLE) testing. In this work, COSMO-RS is used to perform a fast and simplified screening of almost 400 ILs, which led to a shortlist definition of fourteen ILs. For these fourteen ILs, critical solvent properties (i.e., density, viscosity and phase miscibility) were analysed experimentally and compared to simulations in COSMO-RS. Finally, four promising ionic liquids were selected for further LLE- and ME-testing, namely trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([P6,6,6,14][N(Tf)2]), 1-methyl-1-propylpyrro-lidinium bis(trifluoromethylsulfonyl)imide ([C3mPyr][N(Tf)2]), 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C6mim][N(Tf)2]) and triethylsulfonium bis(trifluoromethylsulfonyl)imide ([S2,2,2][N(Tf)2]). Based on wettability testing of four polymeric porous substrates (i.e., PTFE, PES, PSf and PVDF), the PTFE-support was chosen for the stability tests, due to its very high hydrophobicity. The LLE- and stability tests showed that [P6,6,6,14][N(Tf)2] has the highest MBA/IPA- and MPPA/IPA-selectivity and the best SLM-stability of all the tested ILs. Comparative SLM-testing with the benchmarking solvent undecane showed that the IL [P6,6,6,14][N(Tf)2] has a higher SLM-selectivity than undecane at elevated temperatures, while no decrease in its stability was observed.

Highly Efficient Pertraction of Tetravalent Neptunium Ions Across a Flat Sheet Supported Liquid Membrane Containing Two Different Aza-Crown Ether-Based Multiple Diglycolamide Ligands

ABSTRACT Pertraction of Np(IV) across a PTFE membrane containing two different aza-crown ether-based multiple diglycolamide (DGA) ligands termed as L I (3 DGA arms) or L II (4 DGA arms) was investigated using nitric acid as feed solution. A few of the studies were also carried out with Pu(IV) for comparison purposes. The kinetics of the extraction of Np(IV) and Pu(IV) was fast at 3 M HNO3 and within 10 min reaches the equilibrium distribution (D) ratio with both ligands. However, the stripping kinetics was slower especially with ligand L II . The extraction and transport studies were carried out using 1.0 × 10−3 M ligand solution in 95% n-dodecane + 5% isodecanol. The transport rates were slower with ligand L II than with L I at higher nitric acid concentrations (>1 M HNO3) and the transport rates decreased with nitric acid concentration with both ligands. The effective diffusion coefficients (D eff) of Np(IV) were estimated using the lag-time method as 6.2 × 10−8 cm2 s−1 (L I ) and 4.6 × 10−8 cm2 s−1 (L II ). The stability data suggest that the L I containing supported liquid membrane (SLM) is comparatively more stable than that of L II and the transport flux remains the same up to nine days of operation in case of ligand L I .