Liquid Membrane Technology Research Articles

β-Lactoglobulin separation from whey protein: A comprehensive review of isolation and purification techniques and future perspectives

Cow milk, although rich in essential nutrients, is a well-known allergic food that can cause allergic reactions in infants and young children. β-Lactoglobulin accounts for 10% of the total protein in milk and 50% of the whey protein, which has high nutritional value and excellent functional properties but is also the main allergen leading to milk protein allergy. Exploring the mechanism of milk allergy and selecting suitable separation and purification methods to obtain high-purity β-Lactoglobulin is the premise of research on reducing allergenicity. In this review, the research progress in membrane technology, gel filtration chromatography, ion exchange chromatography, affinity chromatography, precipitation and aqueous 2-phase system separation for the separation and purification of milk β-Lactoglobulin is reviewed in detail to promote the further development of milk β-Lactoglobulin separation and purification methods and provide a new method for the development of hypoallergenic dairy products in the future. Among these methods, ion exchange chromatography and gel chromatography are widely used, precipitation is generally used as a crude purification step, and high-performance liquid chromatography and membrane technology are used for further purification to improve the purity of allergens.

Hollow fiber liquid membrane: A promising approach for elimination of pharmaceutical compounds from wastewater

Pharmaceutical compounds present in water pose significant challenges, particularly due to their low concentrations in water streams. Hollow fiber liquid membranes provide a flexible and easily manageable solution, enabling the concentration of specific contaminants. This concentration step significantly improves their effective removal from water systems. The study focused on using hollow fiber liquid membrane technology to effectively remove diclofenac (DCF) and ibuprofen (IBU), two pharmaceutical compounds. A concentration of 40% Cyanex 923 (Cy923) dissolved in kerosene was selected as the preferred extractant due to its stability and quick extraction properties. The stability of the system was tested with a pseudo-emulsion, enabling repeated use of the system. Additionally, an analytical model was developed to calculate the membrane's permeability. In order to enhance the degradation and mineralization of the pharmaceutical compounds and their byproducts, ozonation was integrated with the hollow fiber liquid membrane system in a single system. Measurement of total organic carbon (TOC) revealed a significant reduction of 72% for diclofenac and 57% for ibuprofen with an initial ozone concentration of 10 mg/L and operating under the optimal conditions of hollow fiber liquid membrane.

Separation of phenolic compounds from fruit processing wastewater using liquid membrane technology: A short review

Phenolic compounds are components of secondary metabolites primarily present in fruits, vegetables and grains. These compounds have gained significant attention from the food, pharmaceutical, and cosmetic industries due to their antioxidant properties, which can provide health benefits to humans. Phenolic compounds can be extracted from natural or secondary sources. Nevertheless, the global focus on sustainability has led industries to consider the recovery of phenolic compounds from secondary sources, such as fruit processing wastewater. Various technologies have been proposed and tested for the removal of phenolic compounds, including solvent extraction, adsorption, distillation, and others. However, the aforementioned methods required additional post-treatment in order to recover phenolic compounds. Liquid membrane (LM) technology has emerged as a highly efficient method for removing and recovering of phenolic compounds from various sources of feed phase due to its simultaneous removal and recovery process, simple operation, low chemical, and energy consumption. The purpose of this short review is to highlight the potential application of LM technology by assessing its effectiveness in the separation of phenolic compounds from fruit processing wastewater. By utilizing LM technology, it is possible to efficiently remove and recover phenolic compounds from fruit processing wastewater, thereby reducing environmental pollution, and enabling sustainable production of these valuable compounds.

Efficient removal of Cr (VI) from wastewater using recycled polymer-based supported ionic liquid membrane technology

Hexavalent chromium (Cr (VI)) is a hazardous form of chromium that poses a significant threat to human health and the environment. Meanwhile, Polyethylene Terephthalate (PET) bottles, despite their widespread use and practicality, contribute substantially to the plastic waste problem. Converting waste PET bottles into polymeric membranes offers significant promise. Supported ionic liquid membrane (SILM) technology is a relatively new technique that shows the potential to treat contaminated water efficiently. Experimental studies have demonstrated the influence of different operating conditions on Cr (VI) separation using SILM. The key parameters include concentrations of the feed phase, carrier (Aliquat 336), and strip phase (HCl) and their interactions. Around 98% of Cr (VI) can be removed at a feed concentration of 25 mg/l, a carrier concentration of 5%, and 0.5 M of HCl as a stripping agent. The optimal carrier concentration for membrane extraction was 5% (v/v), leading to a maximum removal rate of 98.34% at optimized values. To assess the impact of carrier concentration on the membrane, SEM-EDS mapping was done. The successful wastewater treatment from such an innovative approach enables handling plastic management and water pollution.

Recovery of copper and silver from industrial e-waste leached solutions using sustainable liquid membrane technology: a review

Waste electrical and electronic equipment or e-waste has recently emerged as a significant global concern. This waste contains various valuable metals, and via recycling, it could become a sustainable resource of metals (viz. copper, silver, gold, and others) while reducing reliance on virgin mining. Copper and silver with their superior electrical and thermal conductivity have been reviewed due to their high demand. Recovering these metals will be beneficial to attain the current needs. Liquid membrane technology has appeared as a viable option for treating e-waste from various industries as a simultaneous extraction and stripping process. It also includes extensive research on biotechnology, chemical and pharmaceutical, environmental engineering, pulp and paper, textile, food processing, and wastewater treatment. The success of this process depends more on the selection of organic and stripping phases. In this review, the use of liquid membrane technology in treating/recovering copper and silver from industrial e-waste leached solutions was highlighted. It also assembles critical information on the organic phase (carrier and diluent) and stripping phase in liquid membrane formulation for selective copper and silver. In addition, the utilization of green diluent, ionic liquids, and synergist carrier was also included since it gained prominence attention latterly. The future prospects and challenges of this technology were also discussed to ensure the industrialization of technology. Herein, a potential process flowchart for the valorization of e-waste is also proposed.

Short review on liquid membrane technology and their applications in biochemical engineering

As a branch of membrane separation technology, liquid membrane has attracted great attention and expanded investigations in biological chemical engineering, with life and health concern in ecosystems. Composed of membrane solvent and mobile carrier, liquid membrane was acquired of function, performing the facilitated mass transfer across the diffusive solvent, so as for the separation and delivery achievement with efficacy. In this review, two types of liquid membrane are mainly focused, respectively on supported liquid membrane (SLM) of membrane solvent supporter in necessity, and on emulsion liquid membrane (ELM) of the required interfacial stabilizers and homogenization. Accordingly, the transfer mechanism, compositions, structure and features of SLM and ELM are introduced respectively. Moreover, the current investigations of liquid membrane have been discussed, focusing on the improvements of efficacy and stability in separation & detection, encapsulation and delivery, so as to scale up the favorable and efficient application with bio-life concern. Prospectively, this review could provide comprehensive insight into the bio-applications of liquid membrane, and guidelines for the further investigations on the efficacy and long-term applicable stability, in order to realize the industrialization.

Recent Advances in Supported Ionic Liquid Membrane Technology in Gas/Organic Compounds Separations

Abstract: The development of the convenient separation processes is a major challenge being examined by scientists and technologists due to its industrial applications. The supported liquid membrane (SLM) technology has been widely employed to separate several species, like permeable gas from binary gaseous mixtures, metal ions, and organic and biological compounds. The main reason for the limited use of SLMs in the industry is their short life and less stability due to the high volatility of traditional organic solvents. Room-temperature ionic liquids (RTILs) are environmentally benign designer salts, exhibit negligible volatility, show good thermal stability, and have remarkable solubility, thus, acting as an alternative solvent to overcome the drawbacks of SLMs. Besides, the high viscosity of ionic liquids (ILs) offers good capillary force, which prevents their flow into membrane pores even under high pressure. Moreover, their tuned properties make them amenable compounds for their immobilization into membrane pores to provide supported ionic liquid membranes (SILMs) with good mechanical strength. In literature (from 2007 to the present), a variety of SILMs have been designed, synthesized, and employed in the field of separation science. This review is mainly focused on the applications of SILMs in the separation of more permeable gases (CO2, O2, CO, H2, and C2H4) from binary gas mixtures as well as the separation of organic compounds (organic acids, alcohols, aromatic hydrocarbons, amines, reactants and products of transesterification reaction, nitrogen- and sulfur-containing aromatic compounds) from distinct mixtures.

Emulsion Liquid Membrane Screening for Ibuprofen Removal from Aqueous Solution

Ibuprofen (IBP) has become increasingly widespread in our environment, posing a major problem for treatment by its high occurrence in low concentrations. Emulsion liquid membrane (ELM) technology has emerged as an alternative solution for removing low concentration pollutants from contaminated sources. This study screened ELM formulations for the removal of IBP from an aqueous solution. Emulsion screening was conducted using a series of reactants, including petroleumbased diluent, green diluent, and acidic/alkaline stripping agent. The ELM system, which included hexane (diluent), 0.1 M sodium carbonate, Na2CO3 (stripping agent), 2 wt% Aliquat 336 (carrier) and 4 wt% Span 80 (surfactant), achieved the highest IBP extraction efficiency of 97%.

Separation of Crystal Violet Dye from Wastewaters by Using Supported Liquid Membrane Technology

The current study enumerates the use of supported liquid membrane (SLM) technology to remove and recover crystal violet dye from wastewaters. The management of textile industry waste effluents is one of the main concerns of environmental health experts due to having excessive concentrations of dyes and resistance to biodegradation. Liquid membranes offer an affordable and green method for the selective removal of dyes from aqueous solutions. To create a liquid membrane, refined and edible vegetable oils were supported on microporous polymeric films of polypropylene (PP1E). Various parameters influencing transport, such as pH range in the feed solution, initial dye concentration, acid concentration in the strip solution, oil viscosities, and membrane lifetime, have been studied. The maximum flux value ( 1.7 × 10 − 5 mg/cm2/s) for crystal violet dye was obtained with sunflower oil-supported membrane at a pH of 12 in the feed solution and a concentration of 0.3 M hydrochloric acid in the strip solution. Under ideal conditions, the maximum amount of dye was transported within 6 hours. Studies on membrane stability and morphology revealed that the flux remained constant up to about 24 hours and then decreased gradually. Morphological studies showed that this may be attributed to deformation of pores shape and gradual clogging.

Separation Iron(III)-Manganese(II) via Supported Liquid Membrane Technology in the Treatment of Spent Alkaline Batteries.

In this paper, the transport of iron(III) from iron(III)-manganese(II)-hydrochloric acid mixed solutions, coming from the treatment of spent alkaline batteries through a flat-sheet supported liquid membrane, is investigated (the carrier phase being of Cyanex 923 (commercially available phosphine oxide extractant) dissolved in Solvesso 100 (commercially available diluent)). Iron(III) transport is studied as a function of hydrodynamic conditions, the concentration of manganese and HCl in the feed phase, and the carrier concentration in the membrane phase. A transport model is derived that describes the transport mechanism, consisting of diffusion through a feed aqueous diffusion layer, a fast interfacial chemical reaction, and diffusion of the iron(III) species-Cyanex 923 complex across the membrane phase. The membrane diffusional resistance (Δm) and feed diffusional resistance (Δf) are calculated from the model, and their values are 145 s/cm and 361 s/cm, respectively. It is apparent that the transport of iron(III) is mainly controlled by diffusion through the aqueous feed boundary layer, this being the thickness of this layer calculated as 2.9 × 10−3 cm. Since manganese(II) is not transported through the membrane phase, the present system allows the purification of these manganese-bearing solutions.

A study of synergetic carrier emulsion liquid membrane for the extraction of amoxicillin from aqueous phase using response surface methodology

Amoxicillin (AMX) is the most commonly used antibiotic in life. AMX was extracted from aqueous solution by synergetic carrier emulsion liquid membrane (ELM) technology for the first time. The membrane phase of ELM was mainly composed of kerosene and butyl acetate. The carrier has consisted of Aliquat-336 and TOA, the surfactant was Span-80, and the membrane enhancer was liquid paraffin. And Na2CO3 and NaCl were used as the internal aqueous phase for extraction. Firstly, the basic structure and mechanism of emulsion were characterized and analyzed. And then, the center composite design (CCD) of response surface methodology (RSM) was used to optimize the operating conditions. The optimal values were: Aliquat-336 concentration (1.1% v/v), trioctylamine (TOA) concentration (8.6% v/v), and extraction time (15 min), AMX concentration (75 mg/L). A polynomial model was fitted to predict the extraction yield of AMX. Under the optimal operating conditions, the optimal extraction prediction value was 98.58%, the extraction actual value was 98.2%, and the recovery rate of AMX was 75.3%.

On the Separation of Yttrium-90 from High-Level Liquid Waste: Purification to Clinical-Grade Radiochemical Precursor, Clinical Translation in Formulation of 90Y-DOTATATE Patient Dose.

Introduction: The quality control parameters of in-house-produced 90Y-Acetate from high-level liquid waste (HLLW) using supported liquid membrane (SLM) technology were validated and compared with the pharmacopeia standard. The radiolabeling of DOTATATE yielding 90Y-DOTATATE in acceptable radiochemical purity (RCP), with expected pharmacological behavior in in vivo models, establish the quality of 90Y-Acetate. Clinical translation of 90Y-Acetate in formulation of 90Y-DOTATATE adds support toward its use as clinical-grade radiochemical. Methods: Quality control parameters of 90Y-Acetate, namely radionuclide purity (RNP), were evaluated using β- spectrometry, γ-spectroscopy, and liquid scintillation counting. RCP and metallic impurities were established using high-performance liquid chromatography and inductively coupled plasma optical emission spectrometry, respectively. The suitability of 90Y-Acetate as an active pharmaceutical ingredient radiochemical was ascertained by radiolabeling with DOTATATE. In vivo biodistribution of 90Y-DOTATATE was carried out in nude mice bearing AR42J xenografted tumor. Clinical efficacy of 90Y-DOTATATE was established after using in patients with large-volume neuroendocrine tumors (NET). Bremsstrahlung imaging was carried out in dual-head gamma camera with a wide energy window setting (100-250 keV). Results: In-house-produced 90Y-Acetate was clear, colorless, and radioactive concentration (RAC) in the range of 40-50 mCi/mL. RCP was >98%. 90Sr content was <0.85 μCi/Ci of 90Y. Gross λ content was <0.8 nCi/Ci of 90Y and no γ peak was observed. Fe3+, Cu2+, Zn2+, Cd2+, and Pb2+ contents were <1.7 μg/Ci. The radiolabeling yield (RLY) of 90Y-DOTATATE was >94%, RCP was >98%. The in vitro stability of 90Y-DOTATATE was up to 72 h postradiolabeling, upon storage at -20°C. Post-therapy (24 h) Bremsstrahlung image of patients with large NET exhibit complete localization of 90Y-DOTATATE in tumor region. Conclusions: This study demonstrates that the in-house-produced 90Y-Acetate from HLLW can be used for the formulation of various therapeutic 90Y-based radiopharmaceuticals. Since 90Y is an imported radiochemical precursor available at a high cost in India, this study which demonstrates the suitability of indigenously sourced 90Y, ideally exemplifies the recovery of "wealth from waste." The Clinical Trial Registration number: (P17/FEB/2019).

Recovery of zinc from electroplating wastewater using green emulsion liquid membrane

Abstract In this research study, removal of zinc ions from the industrial wastewater was investigated using green emulsion liquid membrane technology. The liquid membrane was prepared by using waste cooking oil along with the surfactant, SPAN 80 and the internal phase, sulfuric acid. The extraction percentage of zinc increased with the increase in concentration of surfactant. The response surface methodology (RSM) analysis identified that the optimal variable values for the maximum extraction of zinc were: external pH – 3.8, surfactant concentration 4% (vol.), internal phase concentration – 1.61N, zinc concentration – 742 mg/L, external phase to emulsion volume ratio – 0.94 and carrier concentration – 8.9%. At the optimized conditions experiment was carried out and the maximum extraction was found to be 97.4%. The perturbation plot shows that the extraction of zinc was affected by variables in the following order of effect: zinc concentration &amp;gt; surfactant concentration &amp;gt; carrier concentration &amp;gt; external pH &amp;gt; external phase to emulsion volume ratio &amp;gt; internal phase concentration.

Separation of Volatile Fatty Acids from Model Anaerobic Effluents Using Various Membrane Technologies.

Effluents of anaerobic processes still contain valuable components, among which volatile fatty acids (VFAs) can be regarded and should be recovered and/or used further in applications such as microbial electrochemical technology to generate energy/energy carriers. To accomplish the separation of VFAs from waste liquors, various membrane-based solutions applying different transport mechanisms and traits are available, including pressure-driven nanofiltration (NF) and reverse osmosis (RO) which are capable to clarify, fractionate and concentrate salts and organics. Besides, emerging techniques using a membrane such as forward osmosis (FO) and supported liquid membrane (SILM) technology can be taken into consideration for VFA separation. In this work, we evaluate these four various downstream methods (NF, RO, FO and SILM) to determine the best one, comparatively, for enriching VFAs from pH-varied model solutions composed of acetic, butyric and propionic acids in different concentrations. The assessment of the separation experiments was supported by statistical examination to draw more solid conclusions. Accordingly, it turned out that all methods can separate VFAs from the model solution. The highest average retention was achieved by RO (84% at the applied transmembrane pressure of 6 bar), while NF provided the highest permeance (6.5 L/m2hbar) and a high selectivity between different VFAs.

Selective separation of tungsten from the model and industrial effluents through supported liquid membrane

In this study, a selective separation of tungsten W (VI) from a mixed salt solution was done through a liquid-membrane technology. The transport of W (VI) across the supported liquid membrane was also applied on real sample. Tertiary amine (Tri-n-dodecylamine) was used as an organic carrier and a supported liquid membrane of polypropylene separator (celgard 2400) was used in this experimental work. The selective separation of W (VI) was optimized by various parameters i.e., concentration of metal in feed, concentartion of stripping agent, type of stripping reagents, carrier concentration and pH effect. The extraction of W(VI) was maximized by the concentration of carrier up to 0.2 mol/dm3 diluted in n-hexane. The optimum concentration of sodium hydroxide was 0.2 mol/dm3 in the strip phase. The transport of tungsten increases by the increase of the pH of feed solution to basic from acidic up to the pH 8. At pH 8 in the feed phase, tri-n-dodecylamine efficiently extracted W (VI) from feed through anion exchange mechanism. The time duration for the transport of tungsten was 6 h at room temperature. The optimized reaction of W(VI) for the selective separation was applied on the scheelite ore with 93% recoved. The single membrane was used in all experiments, which confirmed the durability and stability of polypropylene membrane.

Flue Gas Water Recovery by Indirect Cooling Technology for Large-Scale Applications: A Review

With social development and economic enhancement, energy is facing significant worldwide demand, and fossil fuels are the prime energy sources for various energy systems over past decades. Furthermore, among fuel-consumed applications, power plants are the primary source of energy consumption. There is a lot of waste heat and steam accompanied by the latent heat produced in the exhaust flue gas. Therefore, the latent heat recovery from the flue gas plays an important role in increasing the efficiency of the system and saving water. To recover the heat and mass in power plants, three primary methods are proposed to condense the vapor based on previous studies: (1) flue gas condensation technology, (2) liquid desiccant-based dehydration (LDD) technology and (3) membrane technology. This paper mainly reviews and summaries the indirect cooling technology in flue gas condensation technology. The numerical simulation and theory of flue gas condensation are introduced. Different heat exchanger types and conducted experiments are also summarized. The performance of the indirect cooling technology is affected not only by its own configuration and design but also by the flue gas inlet temperature, velocity, water vapor mass fraction, etc. The major concerns and outlook of practical applications for further study are attributed to the heat exchanger size and cost, acid corrosion, ash accumulation in flue gas, etc.

Phenol recovery using continuous emulsion liquid membrane (CELM) process

Liquid membrane technology in batch operation is not quite feasible at industrial level. Hence, a continuous emulsion liquid membrane (CELM) process was conducted in this study to extract phenol from liquid waste solution. An extractor of 1.5 L equipped with baffles was used for well mixed during the extraction process. ELM formulation consists of a mixture of kerosene and palm oil, span 80 and sodium hydroxide as a diluent, surfactant, and strippant, respectively. Meanwhile, 300 ppm of simulated phenol wastewater was used as a feed phase. ELM was found to be stable at 3% (w/v) of Span 80, 5 min of emulsification time and 1300 rpm of emulsification speed. Then, parameters influencing recovery were optimized using the response surface methodology including rotational speed (400 to 800 rpm), treat ratio (1:3 to 1:10) and retention time (2 to 6 min). Increasing rotational speed, treat ratio, and retention time up to 527 rpm, 1:4 and 4 min, respectively offer high recovery efficiency of phenol when achieving about seven times enrichment in the internal phase (2100 ppm).

Removal of-Copper Ions-from Aqueous Solution Using Liquid-Surfactant-Membrane Technique

Extraction of copper (Cu) from aqueous solution utilizing Liquid Membrane technology (LM) is more effective than precipitation method that forms sludge and must be disposed of in landfills. In this work, we have formulated a liquid surfactant membrane (LSM) that uses kerosene oil as the main diluent of LSM to remove copper ions from the aqueous waste solution through di- (2-ethylhexyl) phosphoric acid - D2EHPA- as a carrier. This technique displays several advantages including one-stage extraction and stripping process, simple operation, low energy requirement, and. In this study, the LSM process was used to transport Cu (II) ions from the feed phase to the stripping phase, which was prepared, using H2SO4. For LSM process, various parameters have been studied such as carrier concentration; treat ratio (TR), agitating speed and initial feed concentration. After finding the optimum parameters, it was possible to extract Cu up to 95% from the aqueous feed phase in a single stage extraction.

Selective Removal of Malachite Green Dye from Aqueous Solutions by Supported Liquid Membrane Technology.

A lab-scale study on the application of supported liquid membranes (SLM) has been conducted for recovery and selective removal of Malachite Green dye from wastewater. Naturally occurring non-toxic vegetable oils have been used as membrane liquids. Polyvinylidene fluoride (PVDF) films have been used as supports for the liquid membrane. Various parameters affecting the dye permeation such as initial dye concentration, pH, stripping acid concentration, oil viscosity and membrane stability have been investigated. The highest flux value (1.65 × 10−5 mg/cm2/sec) was obtained with a sunflower oil supported membrane at pH 11 in the feed and 0.25 M HCl in the stripping solution. The membrane showed good stability under optimum conditions and maximum transport was achieved in 8 h of permeation time.

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.