Polymer Inclusion Membranes Research Articles

Kinetic control aspects and mechanisms in oriented membrane processes for extraction and recovery of ascorbic acid compound.

Ascorbic acid comprises four enantiomers, with only one of them, L-ascorbic acid, recognized as vitamin C. The modern industries place significant importance on obtaining this compound in its purest form. The challenge is to recover L-ascorbic acid, which requires specific processes within these industries. To satisfy this condition, purification is needed, a process that requires large quantities of solvents and high energy consumption. To overcome these limitations, we conducted a study on the facilitated extraction of L-ascorbic acid using three affinity polymer membranes, including supported liquid membrane (SLM), polymer inclusion membrane (PIM), and grafted polymer membranes (GPM) with cholic acid as the extractive agent. Following the characterization of the membranes using IR spectroscopy and SEM techniques, we investigated various parameters associated with substrate diffusion through the organic membrane phase. Regarding the biologically active L-ascorbic acid, our research findings indicated that kinetic factors drove the mechanisms of the studied processes.

Transformations of Critical Lithium Ores to Battery-Grade Materials: From Mine to Precursors

The escalating demand for lithium has intensified the need to process critical lithium ores into battery-grade materials efficiently. This review paper overviews the transformation processes and cost of converting critical lithium ores, primarily spodumene and brine, into high-purity battery-grade precursors. We systematically examine the study findings on various approaches for lithium recovery from spodumene and brine. Dense media separation (DMS) and froth flotation are the most often used processes for spodumene beneficiation. Magnetic separation (MS) and ore gravity concentration techniques in spodumene processing have also been considered. To produce battery-grade lithium salts, the beneficiated-concentrated spodumene must be treated further, with or without heat, in the presence of acidic or alkaline media. As a result, various pyro and hydrometallurgical techniques have been explored. Moreover, the process of extracting lithium from brine through precipitation, liquid–liquid extraction, and polymer inclusion membrane separation employing different organic, inorganic, and composite polymer sorbents has also been reviewed.

Evaluation of Polymer Inclusion Membrane Containing Copoly Eugenol Divinyl Benzene 10% as a Carrier for Phenol Transport

Phenol is a toxic and organic compound that often contaminates water, posing significant environmental hazards. To resolve this issue, we conducted research on phenol transport using the Polymer Inclusion Membrane (PIM) method, employing Copoly Eugenol Divinyl Benzene (Co-EDVB) 10% as a carrier compound. The primary objective of this research was to assess the stability and capability of the PIM membrane. Our findings revealed that membrane stability was achieved with a plasticizer concentration of 3.32%. The addition of NaNO3 salt to the source phase yielded the most promising outcomes compared to other types of salt, facilitating the transport of 85.84% of phenol. When NaNO3 0.01 M was introduced in both the source and receiving phases, the transport efficiency increased to 89.93% and 86.76%, respectively. In order to evaluate the durability of the PIM membrane during repeated use, transportation experiments were conducted five times. Without washing, the membrane successfully transported phenol in amounts of 72.19%, 69.23%, 62.71%, 55.91%, and 48.16% during each successive run. Conversely, with regular washing, the membrane maintained its transport efficiency, achieving 70.85%, 64.10%, 56.72%, 49.26%, and 27.19% for each cycle. Notably, the membrane's lifetime reached only 29 days without the addition of 0.1 M NaNO3 salt. However, with the inclusion of NaNO3 0.1 M salt, its longer extended to 58 days.

Selective removal of organic dyes via polymer inclusion membrane containing a perbenzylated β-cyclodextrin derivative

Organic dyes threaten aquatic ecosystems due to carcino/mutagenic properties, and their removal from wastewater is a crucial issue. The novel PIM (Polymer Inclusion Membrane) containing perbenzylated β-cyclodextrin (CD) derivative was designed as an effective material for the selective removal of organic dyes because the CD characterizes strong affinity to these compounds via inclusion complex formation. The PIM was obtained through standard solvent casting from CTA as a matrix, o-NPOE as a plasticizer, and perbenzylated β-CD as the carrier. The membrane transport was evaluated towards two different types of dyes, cationic (Methylene Blue) and anionic (Acid Orange 7), where the optimal concentration for dye removal was 50 and 75 mg/L, respectively. The efficiency of this process was around 83–90 % after 8 h, when the pH of the source/receiving phase induced the formation of non−/ionic forms of dyes, respectively. The optimal membrane composition based on mass ratio was 11.1:72.2:16.7 for CD:o-NPOE:CTA with a membrane thickness of 0.053 mm. The PIM was characterized by high selectivity dependent on both the pH of each phase used in the transport and the chemical character of the dyes. The molecular mechanism of the removal process was mostly based on the complex inclusion of dyes inside the CD cavity. The activation energies were 8.73 and 13.93 kJ/mol for MB and AO7, respectively. The dyes transport was limited by diffusion. This study provides information about novel PIM with an effective and selective carrier, the perbenzylated β-CD derivative, towards organic dyes.

Selective Co(II) and Ni(II) Separation Using the Trihexyl(tetradecyl)phosphonium Decanoate Ionic Liquid

The room temperature ionic liquid trihexyl(tetradecyl)phosphonium decanoate ([P66614][Dec]) was employed in the liquid-liquid extraction of Co(II) from hydrochloric acid solutions in the presence of Ni(II). The extraction performance in liquid-liquid separations showed a strong dependence on the acid content of the feed aqueous solution. The best performance in terms of extracted cobalt and selectivity was obtained when the feed contained a HCl concentration above 6 M On the contrary, when the experiment was performed in absence of HCl, a lower extraction and Co/Ni selectivity were obtained. This behavior has been rationalized by considering the protonation of the [Dec]− anion and the different Co(II)/Ni(II) speciation in HCl media. Moreover, polymer inclusion membranes (PIMs) were prepared using PVC and [P66614][Dec] at different weight rations. Only the PIM formulated with a 30:70/PVC:[P66614][Dec] weight ratio demonstrated effective extraction of Co(II) from the HCl solution. The extraction efficiency and selectivity of the PIM was comparable to that from biphasic liquid experiments at 8 M HCl. The results of this study constitute a promising background for further practical developments of carboxylate-based ILs applied in Co/Ni separations.

PREPARATION AND CHARACTERIZATION OF POLYMER INCLUSION MEMBRANES BASED ON BIODEGRADABLE CELLULOSE/ALGERIAN CLAY FOR HEAVY METALS REMOVAL FROM WASTEWATER

Separation membranes have gained attention as promising options for water and wastewater treatment due to their financial sustainability, and eco-friendliness. However, practical challenges have limited their application in water separation. To overcome these limitations, inorganic-organic hybrid membranes have been developed in this study. The present work deals with two attractive aspects: (i) economical, through the valorization of a local clay (Algerian kaolin), and (ii) environmental, which is based on the membrane selectivity for metal ions. The principal objective of this work is the development of enhanced nanocomposite membranes. It is achieved with low costs, based on cellulose triacetate (CTA) as a polymeric matrix modified by the addition of a lamellar filler, i.e. yellow clay obtained from Jijel, located in the east of Algeria, and plasticized by dioctyl phthalate (DOP). A further objective of this paper was the treatment of wastewater polluted by lead (Pb2+) and cadmium (Cd2+). The prepared membranes were characterized by various characterization techniques, including scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). All synthetized membranes had an amorphous structure, with homogeneous pore morphology and distribution. Moreover, the presence of nanocomposite clay showed effective integration into the membrane matrix and led to a significant improvement in thermal resistance. These membranes were applied to treat a synthetic aqueous solution contaminated with heavy metals, namely Pb2+ and Cd2+. The results revealed a rejection rate higher than 50%, suggesting the potential effectiveness of a stable and environmentally sustainable polymer inclusion membrane system for water purification.

Polymer-Based Extracting Materials in the Green Recycling of Rare Earth Elements: A Review.

Rare earth elements (REEs) are becoming increasingly important in the development of modern and green energy technologies with the demand for REEs predicted to grow in the foreseeable future. The importance of REEs lies in their unique physiochemical properties, which cannot be reproduced using other elements. REEs are sourced through mining, with global exploration of additional commercially viable mining sites still ongoing. However, there is a growing need for recycling of REEs due to the current supply of REEs not matching the growing demand, the environmental impact of REE mining and processing (the so-called "balance problem"), and the generation of large volumes of harmful electronic waste (e-waste). Industrial REE processing is mainly carried out by hydrometallurgy processes, particularly solvent extraction (SX) and ion exchange (IX) technologies. However, these methods have a significant environmental impact due to their intensive use of harmful and nonsustainable reagents. This Review highlights the development of approaches involving polymer-based extracting materials for REE manufacturing as more sustainable alternatives to current industrial REE processing methods. These materials include supported liquid membranes (SLMs), solvent impregnated resins (SIRs), macro and micro capsules, polymer inclusion membranes (PIMs), and micro polymer inclusion beads (μPIBs). Polymer-based extracting materials have the advantage of more economical regent usage while applying the same extractants used in commercial SX, enabling applications analogous to the current industrial process. These materials can be fabricated by a variety of methods in a diverse range of physical formats, with the advantages and disadvantages of each material type described and discussed in this Review along with their applications to REE processing, including e-waste recycling and mineral processing.

Polymer inclusion membrane for the extraction of oxytetracycline from milk prior to aptamer-based biosensing

Aptamer-based sensing may suffer from severe limitations when applied to complex biological and food samples. To alleviate the interference of matrix elements, we propose the use of a polymer inclusion membrane (PIM) as a simple, yet effective sample clean-up tool prior to aptamer-based sensing. As a proof-of-concept, Aliquat 336 anion exchanger was incorporated into a plasticized cellulose acetate membrane to transport oxytetracycline (OTC) from raw milk into an aqueous NaCl acceptor solution. Efficient transport has been ensured by adding a chelating agent to the raw milk and adjusting the pH to alkaline. The amount of extracted OTC was determined as a function of time and acceptor phase NaCl concentration. The extracted amount was proportional to the raw milk OTC concentration in the investigated 0.22–2.2 µM range. Circular dichroism spectroscopy was used to examine the conformation of an OTC-binding aptamer to evaluate if PIM extracts are compatible with aptamer-based biosensors. Solid phase extraction (SPE) was used as a reference sample pre-treatment technique. The aptamer retained its native conformation in the PIM extract, contrary to the SPE extract, and responded to the presence of OTC. Consequently, the PIM-based extraction is adaptable to aptasensor constructs. Besides its simplicity, it offers a cheaper and greener alternative to other sample preparation procedures.

Modelling of a mechanically enhanced PTFE-PVC composite polymer inclusion membrane for highly selective separation of several transition metal ions

Conventional polymer inclusion membranes (PIMs) exhibit suboptimal mechanical properties. Consequently, new composite PIMs were prepared by a modified solvent evaporation method using a PTFE base membrane, a PVC polymer, and an organic phosphonate extractant. Their chemical compositions and microstructures were analyzed by ATR-FTIR and FESEM. The mechanical and mass transfer properties of the composite PIMs were systematically investigated. The composite PIMs exhibited significantly higher tensile strength (36.86 MPa to 52.77 MPa), reduced tensile strain (76.49 % to 118.49 %), and enhanced bursting strength exceeding 0.2 MPa, compared to conventional PIMs. The Zn2+/Cu2+ were separated with a high separation coefficient of 2003.19 by a retardant-enhanced composite PIM system. A new mass transfer model was developed by analyzing the multilayered structure of composite PIMs in depth. The apparent diffusion coefficient of Zn2+ within PTFE-PVC composite layer (7.76 × 10−14 m2/s) was found to be lower than that within polymer inclusion layer (3.18 × 10−13 m2/s). The optimal regions of polymer inclusion layer thickness, contact area, and time were selected by model calculation for a certain separation task (e.g., purity ≥ 0.97 and yield ≥0.80 for Zn2+ or Cu2+). Finally, the retardant-enhanced composite PIMs were successfully used for selective separation of several other transition metal ions.

Investigation of PVDF‐co‐HPF based ultrafiltration polymer inclusion membrane for the extraction of cadmium ions

AbstractUltrafiltration polymer inclusion membranes (UPIMs) have become increasingly significant for the separation and purification of heavy metals from industrial wastes and wastewater due to their convenience compared to other liquid membranes. A novel process for cadmium separation and recovery has been developed using biodegradable ion carriers, specifically room temperature ionic liquids with various molecular structures. This innovation has greatly enhanced the efficiency and application of UPIMs for cadmium separation, while also providing the membranes with unique functional properties. In this study, various UPIMs were produced using polyvinyl fluoride hexafluoropropylene (PVDF‐co‐HPF) as the base polymer, different plasticizers, and symmetric room temperature ionic liquids as ion carriers. The ability of these membranes to extract cadmium ions was evaluated, demonstrating a removal rate of 9.70 μmol s−1 from a 25 ppm Cd(II) solution under optimum conditions. The selectivity and stability of the optimized UPIM were examined under different conditions to obtain a deeper insight into of its performance. The morphological characteristics of the optimized UPIM were examined using scanning electron microscopy and atomic force microscopy techniques.

Erratum to: Preparation and Characterization of Pyridin-2-amine Functionalized Thiadiazole-Embedded Polymer Inclusion Membrane and Utilization of Its Heavy Metal Transport Efficiency

Erratum to: Preparation and Characterization of Pyridin-2-amine Functionalized Thiadiazole-Embedded Polymer Inclusion Membrane and Utilization of Its Heavy Metal Transport Efficiency

Efficient chromium(VI) removal using trioctylmethylammonium salicylate as the carrier in polymer inclusion membranes.

In this study, the ionic liquid (IL) trioctylmethylammonium salicylate (TOMAS) was prepared and incorporated into a polymer inclusion membrane (PIM) based on cellulose triacetate (CTA) as the polymer for the removal of Cr(VI). Various parameters including the effect of membrane composition (plasticizer and carrier concentration) as well as variables affecting both the feed phase and receiving solution have been investigated. Optimal results were achieved with a PIM made of 50% CTA and 50% TOMAS (% in mass) without the addition of any plasticizer. Using this PIM, Cr(VI) was effectively transported from a feed solution consisting of 10mg L-1 Cr(VI) in 0.01mol L-1 NaNO3 at pH = 2, to a receiving solution containing 0.1mol L-1 NaOH. The transport of Cr(VI) was not affected by the presence of other metals, such as Cr(III), Cd(II), Zn(II), Cu(II), and Ni(II), and a selective recovery rate of 93.61% for both single-ion and mixed-ion solutions after 24h of processing was obtained. Finally, the stability of the membrane was also investigated, with a slight decrease in efficiency observed after 5days of reuse.

Role of the side chain configuration on the effective recovery of phenolic compounds using polymer inclusion membranes based on tertiary amine

Polymer inclusion membranes (PIMs) exhibit great potential in the separation and recovery of valuable materials from wastewater and secondary resources. In this work, the effect of alkyl chain configuration of the functional carriers on the physicochemical properties and permeability of PIMs was investigated. Three tertiary amine isomers with different alkyl chain configurations were selected as carriers: trioctylamine, triisooctylamine, and tris(2-ethylhexyl)amine. Operating conditions like carrier contents, feed solution pH, phenol concentration, and stripping solution properties were also investigated. The results obtained in this study indicate that tertiary amines with less branched alkyl chains perform better phenol transport efficiency. Furthermore, the transport efficiency decreased rapidly with increasing steric hindrance of the carriers. Trioctylamine-based PIM displayed optimal extraction efficiency of 92.8 % and stripping efficiency of 90.8 % due to its lower steric hindrance, higher hydrophilicity, and larger crystallinity. Phenol extraction and stripping efficiencies remained above 85.7 % and 80.8 % after 8 cycles, demonstrating excellent stability.

New Insights on Y, La, Nd, and Sm Extraction with Bifunctional Ionic Liquid Cyphos IL 104 Incorporated in a Polymer Inclusion Membrane.

In this study, an ionic liquid-based polymer inclusion membrane (IL-PIM) made of (50% polymer-50% CyphosIL104) was used to extract and separate the rare earth elements (REEs) Y, La, Nd, and Sm in chloride solutions. The effect of extraction time and pH was studied to optimize the extraction and separation conditions. The four REEs were effectively extracted at pH 4-5 from both single and mixed metals solutions. However, at pH 2, only Y was extracted. The recovery of the extracted REEs from the loaded PIM was achieved using HNO3 and H2SO4. In the case of La, it was quantitatively back-extracted with H2SO4 after a contact time of 1 h, while up to 4 h was necessary to recover 70% of the extracted Y, Sm, and Nd. Extraction isotherms were studied, and the Freundlich isotherm model was the most adequate to describe the interaction between the PIM and the REEs. Finally, the developed PIM was investigated for the extraction of REEs from mixtures containing other metals, which showed great selectivity for the REEs.

Facilitating inorganic arsenic speciation and quantification in waters: Polymer inclusion membrane preconcentration and X-ray fluorescence detection

BackgroundArsenic, classified as a priority pollutant and human carcinogen by the IARC, is subject to stringent regulatory limits in food and water. Among various arsenic species found in water samples, arsenite (As(III)) is identified as the most toxic form. Given the limitations of conventional spectroscopic techniques in speciation analysis, there is a crucial need for innovative and sustainable methodologies that enable arsenic speciation. Simplifying these methodologies is essential for widespread applicability and effective environmental monitoring. ResultsThis study proposes a simple and cost-effective analytical methodology for speciating inorganic arsenic in water samples. The method involves extracting As(III) into a polymer inclusion membrane (PIM) containing the extractant Cyanex 301 (bis(2,4,4-trimethylpentyl) dithiophosphinic acid), followed by analysis using energy dispersive X-ray fluorescence (EDXRF) spectrometry. The concentration of arsenate was measured after a reduction step using a thiosulfate/iodide mixture. This simple methodology allows a limit of quantification for trivalent arsenic (2 μg L−1), which is well below the World Health Organization's recommended maximum permissible level of As in drinking water (10 μg L−1). The method that is developed allows the determination of As at trace levels in waters with naturally occurring arsenic. Significance and noveltyThis study represents a significant advance in the field, providing a novel and efficient methodology for arsenic speciation analysis in water samples. By combining the advantages of polymer inclusion membrane (PIM) extraction with energy dispersive X-ray fluorescence (EDXRF) spectrometry, this study offers a cost-effective and environmentally friendly approach to address the critical issue of arsenic contamination in water sources, thereby contributing to enhanced environmental monitoring and public health protection.

Advancing Sustainable Direct Contact Membrane Distillation: Performance and Stability of Novel Polymer Inclusion Membranes

Novel hydrophobic membranes for direct contact membrane distillation (DCMD) were developed using poly(1,1-difluoroethylene) (PVDF) loaded with the ionic liquid methyltrioctylammonium bis(2-ethylhexyl) phosphate (MTOA-DEHP). These polymer inclusion membranes (PIMs) were fabricated via non-solvent induced phase separation (NIPS). Detailed characterization revealed that MTOA-DEHP significantly enhances the morphological and physicochemical properties of the PIMs. Through a series of DCMD experiments, the membrane’s flux, salt rejection, and stability under varying conditions, including different feed solutions (i.e., synthetic NaCl solution and real seawater from the Atlantic Ocean), were assessed. Our results demonstrate that the PVDF/20 %MTOA-DEHP membrane exhibits superior performance, maintaining consistent transmembrane flux values (8.98 ± 0.61 kg·m−2·h−1) over multiple cycles and achieving high salt rejection rates (>99.9 %). Furthermore, the membrane demonstrates excellent stability, with minimal degradation observed even after prolonged operation. The results affirm the viability of PIMs as a promising avenue for achieving sustainable and efficient desalination via DCMD, particularly in real-world operational scenarios.

Preparation and Characterization of Pyridin-2-amine Functionalized Thiadiazole-Embedded Polymer Inclusion Membrane and Utilization of Its Heavy Metal Transport Efficiency

Preparation and Characterization of Pyridin-2-amine Functionalized Thiadiazole-Embedded Polymer Inclusion Membrane and Utilization of Its Heavy Metal Transport Efficiency

Exploration of polymer inclusion membrane for nickel recovery from waste printed circuit boards

In this study, the selective recovery of nickel ions from waste printed circuit boards (WPCBs) solution through polymer inclusion membranes (PIMs) containing 5-nonylsalicylaldoxime (ACORGA M5640) as extracting agent and polyvinyl chloride (PVC) as base polymer has been explored. The proposed method utilizes combined process of solvent extraction and PIMs route for the recovery of nickel. As a first step, the copper was solvent extracted using ACORGA M5640 by the previously developed method by our group and further the raffinate of first stage is utilized as feed phase for the nickel recovery. The consequence of carrier concentration on transportation of nickel, pH of feed solution and effect of acidity of stripping agent has also been investigated. The increase in carrier concentration increases the nickel removal efficiency from feed phase to strip phase. Moreover, the increase in concentration of strip phase also increases the nickel ion flux. 99.77 % nickel was selectively recovered from leach liquor using PIMs containing 50 % of ACORGA M5640. Further, PIMs stability and transport studies has been carried out to know the feasibility of its use in recycling of electronic waste.

Effect of Plasticizer Type on Polymer Inclusion Membranes Properties and Performance for Zinc Separation

AbstractThe goal of the present study is to evaluate the effect of plasticizer in PIMs properties and performance for zinc separation. Membranes were prepared by casting a solution containing poly (vinyl chloride) (PVC) as base polymer, di (2‐ethylhexyl) phosphoric acid (D2EHPA) as carrier, and 2‐nitrophenyl octyl ether (NPOE) or tris (2‐butoxyethyl) phosphate (TBEP) as plasticizers. The newly developed PIMs transported practically all ZnII ions from a feed phase at pH 5 to a 1 M H2SO4 stripping phase. The results showed that the transport flux and its efficiency depend on the chemical nature of the plasticizer. It can be perceived that NPOE (with dielectric constant of 23.1) produced the highest transport flux of zinc (J0=1.62±0.05 10−5 mol m−2 s−1). The single ion transport of zinc was significantly higher than the binary and ternary mixtures. In ternary solution, the transport efficiency for metal ions was in the order of ZnII>CuII>NiII. The transport efficiency of the PVC/NPOE/D2EHPA membrane remained constant until the seventh use. The findings of this work will allow the invention of advanced separation technology ensuring the sustainability of metal resources.

Adsorption and transport of acid dye through polymer inclusion membrane with Aliquat 336 and TBP

Colour is typically the initial pollutant identified in wastewater. Membrane separation represents a novel approach to separation processes, with expectations of supplanting many traditional separation systems. The aim of this study is to investigate polymer inclusion membranes (PIMs) consisting of tri octyl methyl ammonium chloride as the carrier, tributylphosphate as the modifier, poly-vinyl chloride as the base polymer and 2-Nitro phenyl pentyl ether as the plasticizer for removing an acid dye (Red Erionyl A-3G) from aqueous solution. The dye adsorption on the membrane surface and its transition to the stripping phase was achieved by placing the membrane between two glass cells. Changing the stripping solution ensured both adsorption on the membrane surface and the transfer of all the dye to the stripping stage. Using a mixture of 0.8 M salicylic acid and 0.8 M NaOH, along with stirring at 1000 rpm during the stripping phase, extraction efficiency reached 98% in the feed phase and 53% in the stripping phase. When 1 M NaOH solution was employed as the stripping solution, the membrane absorbed all the dye within 10 minutes, but there was no transition to the stripping phase. The membrane has a durability of 2 days.Graphical abstract