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17 pages, 6084 KiB

Open AccessArticle

Precise Filtration of Chronic Myeloid Leukemia Cells by an Ultrathin Microporous Membrane with Backflushing to Minimize Fouling

by Jaehyuk Lee, Jeongpyo Hong, Jungwon Lee, Changgyu Lee, Tony Kim, Young Jeong, Kwanghee Kim and Inhwa Jung

Membranes 2023, 13(8), 707; https://doi.org/10.3390/membranes13080707 - 29 Jul 2023

Viewed by 880

Abstract

A cell filtration platform that affords accurate size separation and minimizes fouling was developed. The platform features an ultra-thin porous membrane (UTM) filter, a pumping head filtration with backflush (PHF), and cell size measurement (CSM) software. The UTM chip is an ultrathin free-standing [...] Read more.

A cell filtration platform that affords accurate size separation and minimizes fouling was developed. The platform features an ultra-thin porous membrane (UTM) filter, a pumping head filtration with backflush (PHF), and cell size measurement (CSM) software. The UTM chip is an ultrathin free-standing membrane with a large window area of 0.68 mm², a pore diameter of 5 to 9 μm, and a thickness of less than 0.9 μm. The PHF prevents filter fouling. The CSM software analyzes the size distributions of the supernatants and subnatants of isolated cells and presents the data visually. The D99 particle size of cells of the chronic myeloid leukemia (CML) line K562 decreased from 22.2 to 17.5 μm after passage through a 5-μm filter. K562 cells could be separated by careful selection of the pore size; the recovery rate attained 91.3%. The method was compared to conventional blocking models by evaluating the mean square errors (MSEs) between the measured and calculated filtering volumes. The filtering rate was fitted by a linear regression model with a significance that exceeded 0.99 based on the R² value. The platform can be used to separate various soft biomaterials and afford excellent stability during filtration. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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16 pages, 2278 KiB

Open AccessArticle

Experimental and Modeling Study of the Nanofiltration of Alcohol-Based Molecules and Amino Acids by Commercial Membranes

by Shirin Shahgodari, Jordi Labanda and Joan Llorens

Membranes 2023, 13(7), 631; https://doi.org/10.3390/membranes13070631 - 29 Jun 2023

Viewed by 1075

Abstract

The nanofiltration performance of three commercial membranes was analyzed by the Steric Pore Model (SPM) and the extended Nernst–Planck diffusion equation inside membrane pores. The model was completed with the equation to predict the concentration polarization, and the mass transfer coefficient was determined [...] Read more.

The nanofiltration performance of three commercial membranes was analyzed by the Steric Pore Model (SPM) and the extended Nernst–Planck diffusion equation inside membrane pores. The model was completed with the equation to predict the concentration polarization, and the mass transfer coefficient was determined by considering the presence of a feed spacer. The model parameters that characterized the performance of the membrane were the hydrodynamic coefficient, which accounts for the possible variations in solute size and membrane pore radius, the effective membrane thickness, and the water permeability coefficient. All experiments were conducted at fixed feed pH of 6. The rejections of uncharged solutes (glucose for membranes with a high molecular weight cut-off (MWCO) and glycerol and ethylene glycol for membranes with a low MWCO) allowed the model parameters to be determined. We found that glycerol and ethylene glycol overestimate the membrane pore radius due to their ability to interact with the membrane matrix. Therefore, the rejection of glycine as a small amino acid was explored to characterize the membranes with low MWCO since these molecules do not interact with the membrane matrix and have an almost zero charge at pH values between 4.5 and 6.5. Based on the experimental rejections, it was stated that glucose and glycine could be separated by these membranes operating in continuous diafiltration mode. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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21 pages, 5666 KiB

Open AccessArticle

The Effect of the Rotating Disk Geometry on the Flow and Flux Enhancement in a Dynamic Filtration System

by Jo Eun Park, Tae Gon Kang and Heejang Moon

Membranes 2023, 13(3), 291; https://doi.org/10.3390/membranes13030291 - 28 Feb 2023

Cited by 2 | Viewed by 1483

Abstract

A numerical study was conducted to investigate the effect of rotating patterned disks on the flow and permeate flux in a dynamic filtration (DF) system. The DF system consists of a rotating patterned disk and a stationary housing with a circular flat membrane. [...] Read more.

A numerical study was conducted to investigate the effect of rotating patterned disks on the flow and permeate flux in a dynamic filtration (DF) system. The DF system consists of a rotating patterned disk and a stationary housing with a circular flat membrane. The feed flow is driven by the rotating disk with the angular velocity ranging from 200 to 1000 rpm and the applied pressure difference between inlet and outlet ports. Wheel-shaped patterns are engraved on the disk surfaces to add perturbation to the flow field and improve the permeate flux in the filtration system. Five disks with varying numbers of patterns were used in numerical simulations to examine the effects of the number of patterns and the angular velocity of the disk on the flow and permeate flux in the DF system. The flow characteristics are studied using the velocity profiles, the cross-sectional velocity vectors, the vortex structures, and the shear stress distribution. The wheel-shaped patterns shift the central core layer in the circumferential velocity profile towards the membrane, leading to higher shear stresses at the membrane and higher flux compared to a plain disk. When the number of patterns on the disk exceeded eight at a fixed Reynolds number, there were significant increases in wall shear stress and permeate flux compared to a plain disk filtration system with no pattern. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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14 pages, 1403 KiB

Open AccessArticle

Dealcoholization of Unfiltered and Filtered Lager Beer by Hollow Fiber Polyelectrolyte Multilayer Nanofiltration Membranes—The Effect of Ion Rejection

by Áron Bóna, Áron Varga, Ildikó Galambos and Nándor Nemestóthy

Membranes 2023, 13(3), 283; https://doi.org/10.3390/membranes13030283 - 27 Feb 2023

Cited by 2 | Viewed by 2274

Abstract

Membrane-based beverage dealcoholization is a successful process for producing low- and non-alcoholic beer and represents a fast-growing industry. Polyamide NF and RO membranes are commonly applied for this process. Polyelectrolyte multilayer (PEM) NF membranes are emerging as industrially relevant species, and their unique [...] Read more.

Membrane-based beverage dealcoholization is a successful process for producing low- and non-alcoholic beer and represents a fast-growing industry. Polyamide NF and RO membranes are commonly applied for this process. Polyelectrolyte multilayer (PEM) NF membranes are emerging as industrially relevant species, and their unique properties (usually hollow fiber geometry, high and tunable selectivity, low fouling) underlines the importance of testing them in the food industry as well. To test PEM NF membranes for beer dealcoholization at a small pilot scale, we dealcoholized filtered and unfiltered lager beer with the tightest available commercial polyelectrolyte multilayer NF membrane (NX Filtration dNF40), which has a MWCO = 400 Da, which is quite high for these purposes. Dealcoholization is possible with a reasonable flux (10 L/m²h) at low pressures (5–8.6 bar) with a real extract loss of 15–18% and an alcohol passage of ~100%. Inorganic salt passage is high (which is typical for PEM NF membranes), which greatly affected beer flavor. During the dealcoholization process, the membrane underwent changes which substantially increased its salt rejection values (MgSO₄ passage decreased fourfold) while permeance loss was minimal (less than 10%). According to our sensory evaluation, the process yielded an acceptable tasting beer which could be greatly enhanced by the addition of the lost salts and glycerol. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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26 pages, 13260 KiB

Open AccessArticle

Enhanced Antifouling in Flat-Sheet Polyphenylsulfone Membranes Incorporating Graphene Oxide–Tungsten Oxide for Ultrafiltration Applications

by Raghad M. Al-Maliki, Qusay F. Alsalhy, Sama Al-Jubouri, Adnan A. AbdulRazak, Mohammed Ahmed Shehab, Zoltán Németh, Klara Hernadi and Hasan Sh. Majdi

Membranes 2023, 13(3), 269; https://doi.org/10.3390/membranes13030269 - 24 Feb 2023

Cited by 4 | Viewed by 1521

Abstract

In this study tungsten oxide and graphene oxide (GO-WO_2.89) were successfully combined using the ultra-sonication method and embedded with polyphenylsulfone (PPSU) to prepare novel low-fouling membranes for ultrafiltration applications. The properties of the modified membranes and performance were investigated using Fourier-transform [...] Read more.

In this study tungsten oxide and graphene oxide (GO-WO_2.89) were successfully combined using the ultra-sonication method and embedded with polyphenylsulfone (PPSU) to prepare novel low-fouling membranes for ultrafiltration applications. The properties of the modified membranes and performance were investigated using Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), contact angle (CA), water permeation flux, and bovine serum albumin (BSA) rejection. It was found that the modified PPSU membrane fabricated from 0.1 wt.% of GO-WO_2.89 possessed the best characteristics, with a 40.82° contact angle and 92.94% porosity. The permeation flux of the best membrane was the highest. The pure water permeation flux of the best membrane showcased 636.01 L·m⁻²·h⁻¹ with 82.86% BSA rejection. Moreover, the membranes (MR-2 and MR-P2) manifested a higher flux recovery ratio (FRR %) of 92.66 and 87.06%, respectively, and were less prone to BSA solution fouling. The antibacterial performance of the GO-WO_2.89 composite was very positive with three different concentrations, observed via the bacteria count method. These results significantly overtake those observed by neat PPSU membranes and offer a promising potential of GO-WO_2.89 on activity membrane performance. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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14 pages, 4082 KiB

Open AccessArticle

Vibration Characteristic Analysis of Hollow Fiber Membrane for Air Dehumidification Using Fluid-Structure Interaction

by Caihang Liang, Jiaxing Chen, Nanfeng Li, Yanfang Dong, Tao Zhong, Si Zeng and Chuanshuai Dong

Membranes 2023, 13(2), 233; https://doi.org/10.3390/membranes13020233 - 15 Feb 2023

Viewed by 1078

Abstract

Hollow fiber membrane dehumidification is an effective and economical method of air dehumidification. The hollow fiber membrane module is the critical component of the dehumidification system, which is formed by an arrangement of several hollow fiber membranes. The air stream crosses over the [...] Read more.

Hollow fiber membrane dehumidification is an effective and economical method of air dehumidification. The hollow fiber membrane module is the critical component of the dehumidification system, which is formed by an arrangement of several hollow fiber membranes. The air stream crosses over the fiber bundles when air dehumidification is performed. The fibers vibrate with the airflow. To investigate the characteristics of the fluid-induced vibration of the hollow fiber membrane, the two-way fluid-structure interaction model under the air-induced condition was established and verified by experiments. The effect of length and air velocity on the vibration and modal of a single hollow fiber membrane was studied, as well as the flow characteristics using the numerical simulation method. The results indicated that the hollow fiber membrane was mainly vibrated by fluid impact in the direction of the airflow. When the air velocity was 1.5 m/s~6 m/s and the membrane length was 100~400 mm, the natural frequency of the membrane was negatively correlated with length and positively correlated with air velocity. Natural frequencies were more sensitive to changes in length than changes in air velocity. The maximum equivalent stress and total deformation increased with air velocity and length. The maximum equivalent stress was concentrated at both ends, and the maximum deformation occurred in the middle. The research results provided a basis for the structural design of hollow fiber membranes under flow-induced vibration conditions. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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18 pages, 8607 KiB

Open AccessArticle

Wettability Studies of Capillary PTFE Membranes Applied for Membrane Distillation

by Piotr Woźniak and Marek Gryta

Membranes 2023, 13(1), 80; https://doi.org/10.3390/membranes13010080 - 08 Jan 2023

Cited by 1 | Viewed by 1313

Abstract

In the present study, the membrane distillation (MD) process was studied with the use of commercial polytetrafluoroethylene (PTFE) capillary membranes. For this purpose, both solutions with NaCl concentrations up to 300 g/L and brines contaminated with oil (70–120 mg/L) were used as feeds. [...] Read more.

In the present study, the membrane distillation (MD) process was studied with the use of commercial polytetrafluoroethylene (PTFE) capillary membranes. For this purpose, both solutions with NaCl concentrations up to 300 g/L and brines contaminated with oil (70–120 mg/L) were used as feeds. The membrane’s wetting resistance was tested by conducting long-term experiments for over 3500 h. Using detailed studies, it has been shown that increasing the salt concentration from 35 to 300 g/L resulted in a 50% reduction in the permeate flux. Nevertheless, the membranes retained 100% of the salt rejection after 2000 h of the module’s operation. Moreover, it has been found that performing the MD process with brines contaminated with oil (120 mg/L) led to the wetting of some membranes pores, which it turn resulted in an increase in the distillate’s conductivity to 450 µS/cm after 700 h running the process. The mechanism of pore wetting by oil droplets adsorbed on the membrane’s surface was presented. Finally, the proposed method of membrane cleaning with the use of a solvent allowed restoring the initial MD module’s performance. Consequently, both the permeate flux and distillate conductivity were stable during the MD of the feed containing 35 g/L of NaCl over the next 280 h. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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15 pages, 1547 KiB

Open AccessArticle

The Pseudo-Protic Ionic Liquids TOAH⁺Cl⁻ and TODAH⁺Cl⁻ as Carriers for Facilitated Transport of In(III) from HCl Solutions

by Francisco José Alguacil and Félix Antonio López

Membranes 2023, 13(1), 19; https://doi.org/10.3390/membranes13010019 - 23 Dec 2022

Cited by 2 | Viewed by 1349

Abstract

A study of indium(III) transport across an immobilized liquid membrane using the pseudo-protic ionic liquids TOAH⁺Cl⁻ and TODAH⁺Cl⁻ as carriers has been carried out using batch experiments. Metal transport is investigated as a function of different variables: [...] Read more.

A study of indium(III) transport across an immobilized liquid membrane using the pseudo-protic ionic liquids TOAH⁺Cl⁻ and TODAH⁺Cl⁻ as carriers has been carried out using batch experiments. Metal transport is investigated as a function of different variables: hydrodynamic conditions in the feed (375–1500 min⁻¹) and receiving (500–750 min⁻¹) phases, HCl (0.5–7 M) and indium (0.01–0.2 g/L) concentrations in the feed phase and carrier (1.25–40% v/v) concentration in the membrane phase. Indium is conveniently recovered in the receiving phase, using a 0.1 M HCl solution. Models are reported describing the transport mechanism, which consists of a diffusion process through the feed aqueous diffusion layer, fast interfacial chemical reaction, and diffusion of the respective indium-pseudo-protic ionic liquid through the membrane. The equations describing the rate of transport are derived by correlating the membrane permeability coefficient to diffusional and equilibrium parameters as well as the chemical composition of the respective indium-pseudo-protic ionic liquid system, i.e., the carrier concentration in the membrane phase. The models allow us to estimate diffusional parameters associated with each of the systems; in addition, the minimum thickness of the feed boundary layer is calculated as 3.3 × 10⁻³ cm and 4.3 × 10⁻³ cm for the In-TOAH⁺Cl⁻ and In-TODAH⁺Cl⁻ systems, respectively. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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19 pages, 5353 KiB

Open AccessArticle

A Green Stable Antifouling PEGylated PVDF Membrane Prepared by Vapor-Induced Phase Separation

by Hana Nur Aini, Irish Maggay, Yung Chang and Antoine Venault

Membranes 2022, 12(12), 1277; https://doi.org/10.3390/membranes12121277 - 16 Dec 2022

Viewed by 1659

Abstract

While green solvents are being implemented in the fabrication of polyvinylidene fluoride (PVDF) membranes, most are not compatible with the vapor-induced phase separation (VIPS) process for which relatively low dissolution temperatures are required. Additionally, preparing antifouling green membranes in one step by blending [...] Read more.

While green solvents are being implemented in the fabrication of polyvinylidene fluoride (PVDF) membranes, most are not compatible with the vapor-induced phase separation (VIPS) process for which relatively low dissolution temperatures are required. Additionally, preparing antifouling green membranes in one step by blending the polymer with an antifouling material before inducing phase separation remains extremely challenging due to the solubility issues. Here, the green solvent triethyl phosphate (TEP) was used to solubilize both PVDF and a copolymer (synthesized from styrene monomer and poly(ethylene glycol) methyl ether methacrylate). VIPS was then used, yielding symmetric bi-continuous microfiltration membranes. For a 2 wt% copolymer content in the casting solution, the corresponding membrane P2 showed a homogeneous and dense surface distribution of the copolymer, resulting in a high hydration capacity (>900 mg/cm³) and effective resistance to biofouling during the adsorption tests using bovine serum albumin, Escherichia coli or whole blood, with a measured fouling reduction of 80%, 89% and 90%, respectively. Cyclic filtration tests using bacteria highlighted the competitive antifouling properties of the membranes with a flux recovery ratio after two water/bacterial solution cycles higher than 70%, a reversible flux decline ratio of about 62% and an irreversible flux decline ratio of 28%. Finally, these green antifouling membranes were shown to be stable despite several weeks of immersion in water. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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18 pages, 5224 KiB

Open AccessFeature PaperArticle

Bipolar Membranes Containing Iron-Based Catalysts for Efficient Water-Splitting Electrodialysis

by Hyeon-Bee Song and Moon-Sung Kang

Membranes 2022, 12(12), 1201; https://doi.org/10.3390/membranes12121201 - 28 Nov 2022

Cited by 2 | Viewed by 1702

Abstract

Water-splitting electrodialysis (WSED) process using bipolar membranes (BPMs) is attracting attention as an eco-friendly and efficient electro-membrane process that can produce acids and bases from salt solutions. BPMs are a key component of the WSED process and should satisfy the requirements of high [...] Read more.

Water-splitting electrodialysis (WSED) process using bipolar membranes (BPMs) is attracting attention as an eco-friendly and efficient electro-membrane process that can produce acids and bases from salt solutions. BPMs are a key component of the WSED process and should satisfy the requirements of high water-splitting capability, physicochemical stability, low membrane cost, etc. The water-splitting performance of BPMs can be determined by the catalytic materials introduced at the bipolar junction. Therefore, in this study, several kinds of iron metal compounds (i.e., Fe(OH)₃, Fe(OH)₃@Fe₃O₄, Fe(OH)₂EDTA, and Fe₃O₄@ZIF-8) were prepared and the catalytic activities for water-splitting reactions in BPMs were systematically analyzed. In addition, the pore-filling method was applied to fabricate low-cost/high-performance BPMs, and the 50 μm-thick BPMs prepared on the basis of PE porous support showed several times superior toughness compared to Fumatech FBM membrane. Through various electrochemical analyses, it was proven that Fe(OH)₂EDTA has the highest catalytic activity for water-splitting reactions and the best physical and electrochemical stabilities among the considered metal compounds. This is the result of stable complex formation between Fe and EDTA ligand, increase in hydrophilicity, and catalytic water-splitting reactions by weak acid and base groups included in EDTA as well as iron hydroxide. It was also confirmed that the hydrophilicity of the catalyst materials introduced to the bipolar junction plays a critical role in the water-splitting reactions of BPM. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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22 pages, 6990 KiB

Open AccessArticle

Design of a Gas Permeation and Pervaporation Membrane Model for an Open Source Process Simulation Tool

by Kouessan Aziaba, Christian Jordan, Bahram Haddadi and Michael Harasek

Membranes 2022, 12(12), 1186; https://doi.org/10.3390/membranes12121186 - 25 Nov 2022

Viewed by 1922

Abstract

Gas permeation and pervaporation are technologies that emerged several decades ago. Even though they have discovered increasing popularity for industrial separation processes, they are not represented equally within process simulation tools except for commercial systems. The availability of such a numerical solution shall [...] Read more.

Gas permeation and pervaporation are technologies that emerged several decades ago. Even though they have discovered increasing popularity for industrial separation processes, they are not represented equally within process simulation tools except for commercial systems. The availability of such a numerical solution shall be extended due to the design of a membrane model with Visual Basic based on the solution-diffusion model. Although this works approach is presented for a specific process simulator application, the algorithm can generally be transferred to any other programming language and process simulation solver, which allows custom implementations or modeling. Furthermore, the modular design of the model enables its further development by operators through the integration of physical effects. A comparison with experimental data of gas permeation and pervaporation applications as well as other published simulation data delivers either good accordance with the results or negligible deviations of less than 1% from other data. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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22 pages, 2805 KiB

Open AccessArticle

Effect of Phase Heterogeneity on the Properties of Poly(vinyl alcohol)-Based Composite Pervaporation Membranes

by Svetlana V. Kononova, Roman V. Kremnev, Galina N. Gubanova, Elena N. Vlasova, Elena N. Popova, Milana E. Vylegzhanina and Anatoly Ya. Volkov

Membranes 2022, 12(12), 1185; https://doi.org/10.3390/membranes12121185 - 24 Nov 2022

Viewed by 1036

Abstract

The structure, thermophysical characteristics, and pervaporation properties of composite membranes based on poly(vinyl alcohol) (PVA) are studied in dependence of the film preparation conditions. It is shown that the nature of the supramolecular organization of the composite polymer film determines which of the [...] Read more.

The structure, thermophysical characteristics, and pervaporation properties of composite membranes based on poly(vinyl alcohol) (PVA) are studied in dependence of the film preparation conditions. It is shown that the nature of the supramolecular organization of the composite polymer film determines which of the components of the separated mixtures of toluene and heptane predominantly penetrate through the corresponding pervaporation membrane. The observed structural effects can become more pronounced if the second component of a polymer mixture is purposefully selected (in this case, poly(N,N-dimethylaminoethyl methacrylate) instead of poly(acrylic acid)) or a nano-sized filler that can be well dispersed in the polymer matrix is introduced. Multi-wall carbon nanotubes are introduced into binary PVA-containing polymer blends. The influence of these fillers on the structure and transport properties of the obtained membranes is studied. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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16 pages, 5303 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Open Pore Ultrafiltration Hollow Fiber Membrane Fabrication Method via Dual Pore Former with Dual Dope Solution Phase

by Kyunghoon Jang, Thanh-Tin Nguyen, Eunsung Yi, Chang Seong Kim, Soo Wan Kim and In S. Kim

Membranes 2022, 12(11), 1140; https://doi.org/10.3390/membranes12111140 - 13 Nov 2022

Cited by 1 | Viewed by 2031

Abstract

Hollow-fiber membranes are widely used in various fields of membrane processes because of their numerous properties, e.g., large surface area, high packing density, mass production with uniform quality, obvious end-of-life indicators, and so on. However, it is difficult to control the pores and [...] Read more.

Hollow-fiber membranes are widely used in various fields of membrane processes because of their numerous properties, e.g., large surface area, high packing density, mass production with uniform quality, obvious end-of-life indicators, and so on. However, it is difficult to control the pores and internal properties of hollow-fiber membranes due to their inherent structure: a hollow inside surrounded by a wall membrane. Herein, we aimed to control pores and the internal structure of hollow-fiber membranes by fabricating a dual layer using a dual nozzle. Two different pore formers, polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP), were separately prepared in the dope solutions and used for spinning the dual layer. Our results show that nanoscale pores could be formed on the lumen side (26.8–33.2 nm), and the open pores continuously increased in size toward the shell side. Due to robust pore structure, our fabricated membrane exhibited a remarkable water permeability of 296.2 ± 5.7 L/m²·h·bar and an extremely low BSA loss rate of 0.06 ± 0.02%, i.e., a high BSA retention of 99.94%. In consideration of these properties, the studied membranes are well-suited for use in either water treatment or hemodialysis. Overall, our membranes could be considered for the latter application with a high urea clearance of 257.6 mL/min, which is comparable with commercial membranes. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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18 pages, 9976 KiB

Open AccessArticle

Hydroxytyrosol Enrichment of Olive Leaf Extracts via Membrane Separation Processes

by Costas S. Papageorgiou, Stathis Lymberopoulos, Panagiotis Bakas, Dimitris P. Zagklis, Varvara Sygouni and Christakis A. Paraskeva

Membranes 2022, 12(11), 1027; https://doi.org/10.3390/membranes12111027 - 22 Oct 2022

Cited by 2 | Viewed by 1201

Abstract

Antioxidants isolated from plant materials, such as phenolics, have attracted a lot of attention because of their potential uses. This contributes to the idea of the biorefinery, which is a way to produce useful products from biomass waste. Olea europaea byproducts have been [...] Read more.

Antioxidants isolated from plant materials, such as phenolics, have attracted a lot of attention because of their potential uses. This contributes to the idea of the biorefinery, which is a way to produce useful products from biomass waste. Olea europaea byproducts have been extensively investigated for their large contents in phenolics. Oleuropein is a phenolic compound abundant in olive leaves, with its molecule containing hydroxytyrosol, elenolic acid, and glucose. In this work, olive leaf extracts were treated using different combinations of ultrafiltration and nanofiltration membranes to assess their capacity of facilitating the production of hydroxytyrosol-enriched solutions, either by separating the initially extracted oleuropein or by separating the hydroxytyrosol produced after a hydrolysis step. The best performance was observed when an ultrafiltration membrane (UP010, 10,000 Da) was followed by a nanofiltration membrane (TS40, 200–300 Da) for the treatment of the hydrolyzed extract, increasing the purity of the final product from 25% w/w of the total extracted compounds being hydroxytyrosol when membrane processes were not used to 68% w/w. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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34 pages, 8351 KiB

Open AccessArticle

Critical Assessment of Membrane Technology Integration in a Coal-Fired Power Plant

by Maytham Alabid, Calin-Cristian Cormos and Cristian Dinca

Membranes 2022, 12(9), 904; https://doi.org/10.3390/membranes12090904 - 19 Sep 2022

Cited by 6 | Viewed by 1789

Abstract

Despite the many technologies for CO₂ capture (e.g., chemical or physical absorption or adsorption), researchers are looking to develop other technologies that can reduce CAPEX and OPEX costs as well as the energy requirements associated with their integration into thermal power plants. [...] Read more.

Despite the many technologies for CO₂ capture (e.g., chemical or physical absorption or adsorption), researchers are looking to develop other technologies that can reduce CAPEX and OPEX costs as well as the energy requirements associated with their integration into thermal power plants. The aim of this paper was to analyze the technical and economic integration of spiral wound membranes in a coal-fired power plant with an installed capacity of 330 MW (the case of the Rovinari power plant—in Romania). The study modeled energy processes using CHEMCAD version 8.1 software and polymer membranes developed in the CO₂ Hybrid research project. Thus, different configurations such as a single membrane step with and without the use of a vacuum pump and two membrane steps placed in series were analyzed. In all cases, a compressor placed before the membrane system was considered. The use of two serialized stages allows for both high efficiency (minimum 90%) and CO₂ purity of a minimum of 95%. However, the overall plant efficiency decreased from 45.78 to 23.96% and the LCOE increased from 75.6 to 170 €/kWh. The energy consumption required to capture 1 kg of CO₂ is 2.46 MJ_el and 4.52 MJ_th. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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Review

Jump to: Research

21 pages, 3521 KiB

Open AccessReview

Polymeric Based Hydrogel Membranes for Biomedical Applications

by Sonia Trombino, Roberta Sole, Federica Curcio and Roberta Cassano

Membranes 2023, 13(6), 576; https://doi.org/10.3390/membranes13060576 - 01 Jun 2023

Cited by 6 | Viewed by 1620

Abstract

The development of biomedical applications is a transdisciplinary field that in recent years has involved researchers from chemistry, pharmacy, medicine, biology, biophysics, and biomechanical engineering. The fabrication of biomedical devices requires the use of biocompatible materials that do not damage living tissues and [...] Read more.

The development of biomedical applications is a transdisciplinary field that in recent years has involved researchers from chemistry, pharmacy, medicine, biology, biophysics, and biomechanical engineering. The fabrication of biomedical devices requires the use of biocompatible materials that do not damage living tissues and have some biomechanical characteristics. The use of polymeric membranes, as materials meeting the above-mentioned requirements, has become increasingly popular in recent years, with outstanding results in tissue engineering, for regeneration and replenishment of tissues constituting internal organs, in wound healing dressings, and in the realization of systems for diagnosis and therapy, through the controlled release of active substances. The biomedical application of hydrogel membranes has had little uptake in the past due to the toxicity of cross-linking agents and to the existing limitations regarding gelation under physiological conditions, but now it is proving to be a very promising field This review presents the important technological innovations that the use of membrane hydrogels has promoted, enabling the resolution of recurrent clinical problems, such as post-transplant rejection crises, haemorrhagic crises due to the adhesion of proteins, bacteria, and platelets on biomedical devices in contact with blood, and poor compliance of patients undergoing long-term drug therapies. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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29 pages, 2652 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Microbial Fuel Cell Construction Features and Application for Sustainable Wastewater Treatment

by Hridoy Roy, Tanzim Ur Rahman, Nishat Tasnim, Jannatul Arju, Md. Mustafa Rafid, Md. Reazul Islam, Md. Nahid Pervez, Yingjie Cai, Vincenzo Naddeo and Md. Shahinoor Islam

Membranes 2023, 13(5), 490; https://doi.org/10.3390/membranes13050490 - 30 Apr 2023

Cited by 24 | Viewed by 8312

Abstract

A microbial fuel cell (MFC) is a system that can generate electricity by harnessing microorganisms’ metabolic activity. MFCs can be used in wastewater treatment plants since they can convert the organic matter in wastewater into electricity while also removing pollutants. The microorganisms in [...] Read more.

A microbial fuel cell (MFC) is a system that can generate electricity by harnessing microorganisms’ metabolic activity. MFCs can be used in wastewater treatment plants since they can convert the organic matter in wastewater into electricity while also removing pollutants. The microorganisms in the anode electrode oxidize the organic matter, breaking down pollutants and generating electrons that flow through an electrical circuit to the cathode compartment. This process also generates clean water as a byproduct, which can be reused or released back into the environment. MFCs offer a more energy-efficient alternative to traditional wastewater treatment plants, as they can generate electricity from the organic matter in wastewater, offsetting the energy needs of the treatment plants. The energy requirements of conventional wastewater treatment plants can add to the overall cost of the treatment process and contribute to greenhouse gas emissions. MFCs in wastewater treatment plants can increase sustainability in wastewater treatment processes by increasing energy efficiency and reducing operational cost and greenhouse gas emissions. However, the build-up to the commercial-scale still needs a lot of study, as MFC research is still in its early stages. This study thoroughly describes the principles underlying MFCs, including their fundamental structure and types, construction materials and membrane, working mechanism, and significant process elements influencing their effectiveness in the workplace. The application of this technology in sustainable wastewater treatment, as well as the challenges involved in its widespread adoption, are discussed in this study. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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24 pages, 1834 KiB

Open AccessReview

Membranes Coated with Graphene-Based Materials: A Review

by Despina A. Gkika, Vasiliki Karmali, Dimitra A. Lambropoulou, Athanasios C. Mitropoulos and George Z. Kyzas

Membranes 2023, 13(2), 127; https://doi.org/10.3390/membranes13020127 - 19 Jan 2023

Cited by 6 | Viewed by 2432

Abstract

Graphene is a popular material with outstanding properties due to its single layer. Graphene and its oxide have been put to the test as nano-sized building components for separation membranes with distinctive structures and adjustable physicochemical attributes. Graphene-based membranes have exhibited excellent water [...] Read more.

Graphene is a popular material with outstanding properties due to its single layer. Graphene and its oxide have been put to the test as nano-sized building components for separation membranes with distinctive structures and adjustable physicochemical attributes. Graphene-based membranes have exhibited excellent water and gas purification abilities, which have garnered the spotlight over the past decade. This work aims to examine the most recent science and engineering cutting-edge advances of graphene-based membranes in regard to design, production and use. Additional effort will be directed towards the breakthroughs in synthesizing graphene and its composites to create various forms of membranes, such as nanoporous layers, laminates and graphene-based compounds. Their efficiency in separating and decontaminating water via different techniques such as cross-linking, layer by layer and coating will also be explored. This review intends to offer comprehensive, up-to-date information that will be useful to scientists of multiple disciplines interested in graphene-based membranes. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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