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Membranes
Volume 15
Issue 4
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Membranes, Volume 15, Issue 4 (April 2025) – 31 articles

Cover Story (view full-size image): DNA metabolism involves the critical processes of replication, recombination, transposition, and repair. While previously believed to occur exclusively in the cytoplasm, this classical view has been challenged by mounting evidence that bacterial DNA transactions are closely associated with the cell membrane. Factors influencing these processes include the Hfq protein, an RNA chaperone, increasingly recognized for important roles in DNA-related functions. This narrative review examines the emerging involvement of membranes in bacterial DNA transactions and the potential regulatory functions of Hfq, highlighting its dual affinity for DNA and membranes. View this paper
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14 pages, 2980 KiB  
Article
Modeling of Power Generation and Acid Recovery in an Analogous Process of Reverse Electrodialysis
by Qiaolin Lang, Yang Liu, Gaojuan Guo, Fei Liu and Yang Zhang
Membranes 2025, 15(4), 126; https://doi.org/10.3390/membranes15040126 - 20 Apr 2025
Abstract
The feasibility of an analogous reverse electrodialysis (RED) process for power generation and acid recovery from acidic waste streams in the steel industry is investigated in this study. A comprehensive model was established to simulate the transport phenomena and power generation, which was [...] Read more.
The feasibility of an analogous reverse electrodialysis (RED) process for power generation and acid recovery from acidic waste streams in the steel industry is investigated in this study. A comprehensive model was established to simulate the transport phenomena and power generation, which was validated through experimental data. The simulated operation time was 3 h, during which an acid recovery rate of 41.7% was achieved, and the maximum output power density reached 30.37 μW·cm−2. The results demonstrated a strong dependence of output power density on the acid concentration, with a linear relationship within the tested range of 1.0–3.0 mol·L−1 HCl. An optimal flow rate range was identified that maximized power output, with the best value of 90 mL∙min−1. The differences in energy harvesting between the traditional acid diffusion dialysis process and our analogous RED process were demonstrated via simulation. The importance of system electroneutrality in driving ion migration and forming ionic currents was crucial for effective power generation. The analogous RED process is a promising solution for efficient acid recovery and power generation from industrial acid waste, offering a sustainable treatment approach. Full article
(This article belongs to the Section Membrane Applications for Energy)
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14 pages, 1678 KiB  
Article
Water Recovery from Laundry Wastewater by Integrated Purification Systems
by Aleksandra Klimonda and Izabela Kowalska
Membranes 2025, 15(4), 125; https://doi.org/10.3390/membranes15040125 - 14 Apr 2025
Viewed by 206
Abstract
Integrated systems for water recovery from laundry wastewater were investigated to close the water cycle loop. The grey water from the washing cycle of cotton fabrics with a softening detergent was prefiltered, purified in a low-pressure membrane process, and further purified in a [...] Read more.
Integrated systems for water recovery from laundry wastewater were investigated to close the water cycle loop. The grey water from the washing cycle of cotton fabrics with a softening detergent was prefiltered, purified in a low-pressure membrane process, and further purified in a high-pressure membrane process or alternatively in an adsorption process. In all of the proposed systems, the recovered water was clarified and completely free of cationic surfactants. The system based on nanofiltration as the final stage of purification allows soft water, which promotes better cleaning results, reduces the consumption of detergents, and extends the lifetime of the devices involved. Adsorption on activated carbon effectively reduced the concentration of organic compounds, including fragrance compounds. Full article
(This article belongs to the Special Issue Membrane and Other Innovative Technologies for Water Purification: Design, Development, and Application)
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13 pages, 34194 KiB  
Article
Restricted Surface Diffusion of Cytochromes on Bioenergetic Membranes with Anionic Lipids
by Aaron Chan and Emad Tajkhorshid
Membranes 2025, 15(4), 124; https://doi.org/10.3390/membranes15040124 - 13 Apr 2025
Viewed by 307
Abstract
Bioenergetic membranes of mitochondria, thylakoids, and chromatophores are primary sites of ATP production in living cells. These membranes contain an electron transport chain (ETC) in which electrons are shuttled between a series of redox proteins during the generation of ATP via oxidative phosphorylation. [...] Read more.
Bioenergetic membranes of mitochondria, thylakoids, and chromatophores are primary sites of ATP production in living cells. These membranes contain an electron transport chain (ETC) in which electrons are shuttled between a series of redox proteins during the generation of ATP via oxidative phosphorylation. The phospholipid composition of these membranes, which often include negative lipids, plays a role in determining the electrostatics of their surface owing to the spatial distribution of their charged head groups. Cardiolipin (CDL) is a phospholipid commonly associated with bioenergetic membranes and is also a significant contributor to the negative surface charge. Interactions between cytochromes and phospholipid head groups in the membrane can in principle affect the rate of its travel between ETC components, hence influencing the rate of ATP turnover. Here, we use molecular dynamic (MD) simulations that feature an accelerated membrane model, termed highly mobile membrane mimetic (HMMM), to study protein–lipid interactions during the diffusion of cytochrome c2 between redox partners in a bioenergetic membrane. We observe a “skipping” mode of diffusion for cytochromes along with a bias for binding to anionic lipids, particularly with a strong preference for CDL. During diffusion, cytochrome c2 maintains a relatively fixed tilt with respect to the membrane normal with wider fluctuations in its angle with respect to the plane of the membrane. The obtained results describing the behavior of cytochrome c2 on a representative bioenergetic membrane have direct ramifications in shuttling motions of other similar electron-carrying elements in other bioenergetic membranes, which are composed of a significant amount of anionic lipids. The mode of surface-restricted diffusion reported here would modulate rapid electron transfer between the ETC complexes anchored in bioenergetic membranes by reducing the search space between them. Full article
(This article belongs to the Section Biological Membranes)
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16 pages, 2914 KiB  
Article
Electrochemical Characterization and Simulation of Ion Transport in Anion Exchange Membranes for Water Treatment Applications
by Qiaolin Lang, Yang Liu, Gaojuan Guo and Yang Zhang
Membranes 2025, 15(4), 123; https://doi.org/10.3390/membranes15040123 - 13 Apr 2025
Viewed by 260
Abstract
This study presents a comprehensive electrochemical characterization and simulation of anion exchange membranes (AEMs) for water treatment applications, focusing on ion transport behavior. Experimental techniques, including chronopotentiometry, current–voltage (I–V) curve measurements, and electrochemical impedance spectroscopy (EIS), were employed to investigate the kinetics and [...] Read more.
This study presents a comprehensive electrochemical characterization and simulation of anion exchange membranes (AEMs) for water treatment applications, focusing on ion transport behavior. Experimental techniques, including chronopotentiometry, current–voltage (I–V) curve measurements, and electrochemical impedance spectroscopy (EIS), were employed to investigate the kinetics and dynamics of ion transport at the membrane interface. The results were validated and further explored through finite element method (FEM) simulations using COMSOL Multiphysics. The study revealed key insights into the role of membrane resistance, ion diffusion, and capacitive effects on overall membrane performance. Parametric analyses of electrolyte layer thickness, bulk solution concentration, and membrane porosity provided guidelines for optimizing membrane design. The findings highlight the importance of considering these factors in enhancing the efficiency and applicability of AEMs in water treatment processes. Future work will focus on refining simulation models and exploring advanced materials to further improve membrane performance. Full article
(This article belongs to the Special Issue Research on Electrodialytic Processes)
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10 pages, 2413 KiB  
Article
A Comparison Between Calcium and Strontium Transport by the (Ca2+ + Mg2+)ATPase of the Basolateral Plasma Membrane of Renal Proximal Convoluted Tubules
by José Roberto Meyer-Fernandes, Mauro Sola-Penna and Adalberto Vieyra
Membranes 2025, 15(4), 122; https://doi.org/10.3390/membranes15040122 - 12 Apr 2025
Viewed by 175
Abstract
In this work, the utilization of calcium and strontium by the (Ca2+ + Mg2+)ATPase of the basolateral plasma membrane of renal proximal convoluted tubules were compared. [90Sr]Sr2+ and [45Ca]Ca2+ uptake by vesicles derived from [...] Read more.
In this work, the utilization of calcium and strontium by the (Ca2+ + Mg2+)ATPase of the basolateral plasma membrane of renal proximal convoluted tubules were compared. [90Sr]Sr2+ and [45Ca]Ca2+ uptake by vesicles derived from this membrane were strictly dependent on ATP and Mg2+, and no other nucleotide was able to support the transport. Each cation inhibited the uptake of the other one in a purely competitive fashion (the same Vmax; increased K0.5), without causing a significant change in the influx rate. These results indicate that both cations bind at the same transport site on the enzyme, facing the cytosolic surface of the cell. The K0.5 for Sr2+ obtained for (Sr2+ + Mg2+)ATPase activity was 13.1 ± 0.2 µM and for Sr2+ uptake was 13.4 ± 0.1 µM. They were higher than K0.5 for Ca2+ obtained for (Ca2+ + Mg2+)ATPase activity (0.42 ± 0.03 µM) and for Ca2+ uptake (0.28 ± 0.02 µM). It is postulated that the lower ATPase affinity for Sr2+ is associated with greater steric difficulties for the occupation by this cation of the binding and transport sites, as a consequence of its greater crystal ionic radius (1.13 Å for Sr2+ against 0.99 Å for Ca2+). Full article
(This article belongs to the Section Biological Membranes)
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17 pages, 3054 KiB  
Article
Efficient Separation of a Novel Microbial Chassis, Vibrio natriegens, from High-Salt Culture Broth Using Ceramic Ultrafiltration Membranes
by Stefan Schwarz, Rong Fan, Mehrdad Ebrahimi and Peter Czermak
Membranes 2025, 15(4), 121; https://doi.org/10.3390/membranes15040121 - 11 Apr 2025
Viewed by 255
Abstract
Vibrio natriegens is widely used as a production host for biotechnological processes due to its superior maximum glucose consumption rate, high growth rate, and abundant ribosomes. Most bioprocesses also need a scalable biomass separation step. This can be achieved by cross-flow filtration with [...] Read more.
Vibrio natriegens is widely used as a production host for biotechnological processes due to its superior maximum glucose consumption rate, high growth rate, and abundant ribosomes. Most bioprocesses also need a scalable biomass separation step. This can be achieved by cross-flow filtration with ceramic membranes, although the membrane pores are susceptible to fouling. However, the fouling characteristics of V. natriegens culture broth have not been investigated in detail. We therefore characterized membrane fouling during the separation of V. natriegens biomass from culture broth using a cross-flow filtration plant with ceramic membranes. The resistance in series model was used to quantify the fouling-induced resistance caused by the different components of the culture broth. The total fouling resistance was 4.1·109 ± 0.6·109 m−1 for the culture broth and 5.4·109 ± 0.7·109 m−1 for the summed broth components. Reversible resistance accounted for 86% and 81% of these totals, respectively. We then applied Hermia’s adapted filtration laws to determine the dominant fouling mechanism induced by the different broth components. In a further step, we established a setup to determine the compressibility index of the cells during cross-flow filtration, resulting in an estimated value of 0.55 ± 0.04. These results will facilitate the design of economic filtration plants and will help to establish V. natriegens as a production host for large-scale industrial processes. Full article
(This article belongs to the Special Issue Application of Membrane Materials in Bioseparation and Downstream Processing)
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25 pages, 6238 KiB  
Article
Effect of Ultrasound on Dissolution of Polymeric Blends and Phase Inversion in Flat Sheet and Hollow Fiber Membranes for Ultrafiltration Applications
by Gilberto Katmandú Méndez-Valdivia, María De Lourdes Ballinas-Casarrubias, Guillermo González-Sánchez, Hugo Valdés, Efigenia Montalvo-González, Martina Alejandra Chacón-López, Emmanuel Martínez-Montaño, Beatriz Torrestiana-Sánchez, Herenia Adilene Miramontes-Escobar and Rosa Isela Ortiz-Basurto
Membranes 2025, 15(4), 120; https://doi.org/10.3390/membranes15040120 - 10 Apr 2025
Viewed by 271
Abstract
In seeking alternatives for reducing environmental damage, fabricating filtration membranes using biopolymers derived from agro-industrial residues, such as cellulose acetate (CA), partially dissolved with green solvents, represents an economical and sustainable option. However, dissolving CA in green solvents through mechanical agitation can take [...] Read more.
In seeking alternatives for reducing environmental damage, fabricating filtration membranes using biopolymers derived from agro-industrial residues, such as cellulose acetate (CA), partially dissolved with green solvents, represents an economical and sustainable option. However, dissolving CA in green solvents through mechanical agitation can take up to 48 h. An ultrasonic probe was proposed to accelerate mass transfer and polymer dissolution via pulsed interval cavitation. Additionally, ultrasound-assisted phase inversion (UAPI) on the external coagulation bath was assessed to determine its influence on the properties of flat sheet and hollow fiber membranes during phase inversion. Results indicated that the ultrasonic pulses reduced dissolution time by up to 98% without affecting viscosity (3.24 ± 0.06 Pa·s), thermal stability, or the rheological behavior of the polymeric blend. UAPI increased water permeability in flat sheet membranes by 26% while maintaining whey protein rejection above 90%. For hollow fiber membranes, UAPI (wavelength amplitude of 0 to 20%) improved permeability by 15.7% and reduced protein retention from 90% to 70%, with MWCO between 68 and 240 kDa. This report demonstrates the effectiveness of ultrasonic probes for decreasing the dissolution time of dope solution with green cosolvents and its potential to change the structure of polymeric membranes by ultrasound-assisted phase inversion. Full article
(This article belongs to the Special Issue Membrane Processes for Water Recovery in Food Processing Industries)
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14 pages, 3423 KiB  
Article
Changes in Tubular PVDF Membrane Performance During Initial Period of Pilot Plant Operation
by Marek Gryta and Wirginia Tomczak
Membranes 2025, 15(4), 119; https://doi.org/10.3390/membranes15040119 - 9 Apr 2025
Viewed by 222
Abstract
Ultrafiltration (UF) is increasingly used in the food industry and for wastewater treatment and water reuse. Knowledge of the membrane properties that stabilise during the initial period of module operation in an industrial plant is essential for design purposes. This paper presents the [...] Read more.
Ultrafiltration (UF) is increasingly used in the food industry and for wastewater treatment and water reuse. Knowledge of the membrane properties that stabilise during the initial period of module operation in an industrial plant is essential for design purposes. This paper presents the experimental tests carried out using a pilot plant with an industrial PCI B1 membrane module. The module was equipped with tubular FP100 (100 kDa) polyvinylidene fluoride (PVDF) membranes used to separate carwash wastewater. The effect of membrane compaction during the first few days of the process on changes in permeate flux and dextran (40–500 kDa) separation rate was investigated. The effect of fouling, membrane washing with P3 Ultrasill 11 solution (pH = 12) and maintenance with sodium metabisulfite solution on the stabilisation of the technological performance of the plant was determined. Full article
(This article belongs to the Special Issue Membrane and Other Innovative Technologies for Water Purification: Design, Development, and Application)
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13 pages, 3927 KiB  
Article
Effects of Latent Solvent Content on Tuning the Nanofiltration Performance of Nanofibrous Composite Membranes
by Xu-Dong Cao, Yu-Xuan Shao, Qian Wang, Tian-Dan Lu and Jing Zhong
Membranes 2025, 15(4), 118; https://doi.org/10.3390/membranes15040118 - 8 Apr 2025
Viewed by 161
Abstract
This study aims to optimize the application of electrospun nanofibrous substrates in thin-film composite (TFC) nanofiltration (NF) membranes for enhanced liquid separation efficiency by employing a method of effective welding between fibers using latent solvents. Polyacrylonitrile (PAN) nanofiber substrates were fabricated via electrospinning, [...] Read more.
This study aims to optimize the application of electrospun nanofibrous substrates in thin-film composite (TFC) nanofiltration (NF) membranes for enhanced liquid separation efficiency by employing a method of effective welding between fibers using latent solvents. Polyacrylonitrile (PAN) nanofiber substrates were fabricated via electrospinning, and a dense polyamide selective layer was formed on their surface through interfacial polymerization (IP). The investigation focused on the effects of different solvent systems, particularly the role of dimethyl sulfoxide (DMSO) as a latent solvent, on the nanostructure and final membrane performance. The results indicate that increasing the DMSO content can enhance the greenness of the fabrication process, the substrate hydrophilicity, and the mechanical strength, while also influencing the thickness and morphology of the polyamide layer. At a DMSO rate of 30%, the composite membrane achieves optimal pure water permeability and high rejection rates; when the DMSO content exceeds 40%, structural inhomogeneity in the substrate membrane leads to an increase in defects, significantly deteriorating membrane performance. These findings provide theoretical insights and technical guidance for the application of electrospinning technology in designing efficient and stable NF membranes. Full article
(This article belongs to the Section Membrane Fabrication and Characterization)
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26 pages, 1509 KiB  
Review
The State of the Art on PVDF Membrane Preparation for Membrane Distillation and Membrane Crystallization: Towards the Use of Non-Toxic Solvents
by Aqsa Mansoor Khan, Francesca Russo, Francesca Macedonio, Alessandra Criscuoli, Efrem Curcio and Alberto Figoli
Membranes 2025, 15(4), 117; https://doi.org/10.3390/membranes15040117 - 8 Apr 2025
Viewed by 460
Abstract
Most parts of the earth are covered with water, but only 0.3% of it is available to living beings. Industrial growth, fast urbanization, and poor water management have badly affected the water quality. In recent years, a transition has been seen from the [...] Read more.
Most parts of the earth are covered with water, but only 0.3% of it is available to living beings. Industrial growth, fast urbanization, and poor water management have badly affected the water quality. In recent years, a transition has been seen from the traditional (physical, chemical) wastewater treatment methods towards a greener, sustainable, and scalable membrane technology. Even though membrane technology offers a green pathway to address the wastewater treatment issue on a larger scale, the fabrication of polymeric membranes from toxic solvents is an obstacle in making it a fully green method. The concept of green chemistry has encouraged scientists to engage in research for new biodegradable and non-protic solvents to replace with already existing toxic ones. This review outlines the use of non-toxic solvents for the preparation of PVDF membranes and their application in membrane distillation and membrane crystallization. Full article
(This article belongs to the Topic New Advances in Membrane Technology and Its Contribution to Sustainability)
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16 pages, 2720 KiB  
Article
Ultrapure Water Production by a Saline Industrial Effluent Treatment
by Adriana Hernández Miraflores, Karina Hernández Gómez, Claudia Muro, María Claudia Delgado Hernández, Vianney Díaz Blancas, Jesús Álvarez Sánchez and German Eduardo Devora Isordia
Membranes 2025, 15(4), 116; https://doi.org/10.3390/membranes15040116 - 7 Apr 2025
Viewed by 300
Abstract
A membrane system was applied for ultrapure water production from the treatment of saline effluent from the canned food industry. The industrial effluent presented a high saline concentration, including sodium chloride, calcium carbonate, calcium sulfates, and magnesium. The effluent was treated using a [...] Read more.
A membrane system was applied for ultrapure water production from the treatment of saline effluent from the canned food industry. The industrial effluent presented a high saline concentration, including sodium chloride, calcium carbonate, calcium sulfates, and magnesium. The effluent was treated using a system of reverse osmosis (RO) and a post-treatment process consisting of ion exchange resins (IEXRs). The RO was accompanied by the addition of a hexametaphosphate dose (2, 6, and 10 mg/L) as an antiscalant to avoid the RO membrane scaling by minerals. In turn, IEXRs were used for water deionization to produce ultrapure water with a reduced concentration of monovalent ions. The antiscalant dose was 6 mg/L, producing clean water from RO permeates with an efficiency of 65–70%. The brine from RO was projected for its reuse in food industry processes. The clean water quality from RO showed 20% total dissolved solids (TDS) removal (equivalent to salts). The antiscalant inhibited the formation of calcium salt incrustation > 200 mg/L, showing low fouling. In turn, anionic resins removed 99.8% of chloride ions, whereas the monovalent salts were removed by a mix of cationic–anionic resin, producing ultrapure water with electrical conductivity < 3.3 µS/cm. The cost of ultrapure water production was 2.62 USD/m3. Full article
(This article belongs to the Topic Removing Challenging Pollutants from Wastewater: Effective Approaches)
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17 pages, 6225 KiB  
Article
RF Sputtering of Gold Nanoparticles in Liquid and Direct Transfer to Nafion Membrane for PEM Water Electrolysis
by Chandrakanth Reddy Chandraiahgari, Gloria Gottardi, Giorgio Speranza, Beatrice Muzzi, Domenico Dalessandro, Andrea Pedrielli, Victor Micheli, Ruben Bartali, Nadhira Bensaada Laidani and Matteo Testi
Membranes 2025, 15(4), 115; https://doi.org/10.3390/membranes15040115 - 7 Apr 2025
Viewed by 328
Abstract
Sputtering onto liquids is rapidly gaining attention for the green and controlled dry synthesis of ultrapure catalysts nanomaterials. In this study, we present a clean and single-step method for the synthesis of gold nanoparticles directly in polyethylene glycol (PEG) liquid using radio frequency [...] Read more.
Sputtering onto liquids is rapidly gaining attention for the green and controlled dry synthesis of ultrapure catalysts nanomaterials. In this study, we present a clean and single-step method for the synthesis of gold nanoparticles directly in polyethylene glycol (PEG) liquid using radio frequency (RF) magnetron sputtering and by subsequently transferring them to Nafion ionomer, fabricating a catalyst-coated membrane (CCM), an essential component of the proton exchange membrane water electrolyzer (PEMWE). The samples were systematically characterized at different stages of process development. The innovative transfer process resulted in a monodispersed homogeneous distribution of catalyst particles inside CCM while retaining their nascent nanoscale topography. The chemical analysis confirmed the complete removal of the trapped PEG through the process optimization. The electrochemical catalytic activity of the optimized CCM was verified, and the hydrogen evolution reaction (HER) in acidic media appeared outstanding, a vital step in water electrolysis toward H2 production. Therefore, this first study highlights the advantages of RF sputtering in liquid for nanoparticle synthesis and its direct application in preparing CCM, paving the way for the development of innovative membrane preparation techniques for water electrolysis. Full article
(This article belongs to the Section Membrane Applications for Energy)
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11 pages, 5466 KiB  
Article
Electrocatalytic PANI-Encapsulated Aluminum Silicate/Ceramic Membranes for Efficient and Energy-Saving Removal of 4-Chlorophenol in Wastewater
by Shuo Wang, Tianhao Huang, Haoran Ma, Zihan Liu, Houbing Xia, Zhiqiang Sun, Jun Ma and Ying Zhao
Membranes 2025, 15(4), 114; https://doi.org/10.3390/membranes15040114 - 7 Apr 2025
Viewed by 224
Abstract
The removal of chlorinated organic pollutants from wastewater is a critical environmental challenge, as traditional methods for treating toxic pollutants like phenol and chlorophenols often suffer from high energy consumption and long treatment times, limiting their practical use. Electrocatalytic filtration has emerged as [...] Read more.
The removal of chlorinated organic pollutants from wastewater is a critical environmental challenge, as traditional methods for treating toxic pollutants like phenol and chlorophenols often suffer from high energy consumption and long treatment times, limiting their practical use. Electrocatalytic filtration has emerged as a promising alternative, but efficient, energy-saving electrocatalytic membranes for pollutants like 4-chlorophenol (4-CP) are still underexplored. A new type of electrocatalytic coupling membrane catalyst, ASP/CM (PANI-encapsulated aluminum silicate/ceramic membrane), was prepared using inexpensive silicate and polyaniline as the base materials, with in situ polymerization combined with co-focus magnetron sputtering. Under optimal conditions (25 mA/cm2, 10 mM Na2SO4, 1.0 mL·min−1 flow rate, and 50 μM 4-CP concentration), the membrane achieved about 95.1% removal of 4-CP and the degradation rate after five cycles was higher than 85%. In addition, O2•− and •OH are important active species in the electrocatalytic degradation of 4-CP. The 4-CP electrocatalytic membrane filtration process is a dual process of cathode reduction dechlorination and anodic oxidation. This work offers new insights into developing next-generation electrocatalytic membranes and expands the practical applications of electrocatalytic filtration systems. Full article
(This article belongs to the Special Issue Membrane Catalytic Oxidation in Water Treatment)
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19 pages, 2820 KiB  
Article
Process Simulation of High-Pressure Nanofiltration (HPNF) for Membrane Brine Concentration (MBC): A Pilot-Scale Case Study
by Abdallatif Satti Abdalrhman, Sangho Lee, Seungwon Ihm, Eslam S. B. Alwaznani, Christopher M. Fellows and Sheng Li
Membranes 2025, 15(4), 113; https://doi.org/10.3390/membranes15040113 - 4 Apr 2025
Viewed by 321
Abstract
The growing demand for sustainable water management solutions has prompted the development of membrane brine concentration (MBC) technologies, particularly in the context of desalination and minimum liquid discharge (MLD) applications. This study presents a simple model of high-pressure nanofiltration (HPNF) for MBC. The [...] Read more.
The growing demand for sustainable water management solutions has prompted the development of membrane brine concentration (MBC) technologies, particularly in the context of desalination and minimum liquid discharge (MLD) applications. This study presents a simple model of high-pressure nanofiltration (HPNF) for MBC. The model integrates reverse osmosis (RO) transport equations with mass balance equations, thereby enabling acceptable predictions of water flux and total dissolved solids (TDS) concentration. Considering the limitations of the pilot plant data, the model showed reasonable accuracy in predicting flux and TDS, with R2 values above 0.99. The simulation results demonstrated that an increase in feed flow rate improves flux but raises specific energy consumption (SEC) and reduces recovery. In contrast, an increase in feed pressure results in an increased recovery and brine concentration. Increasing feed TDS decreases flux, recovery, and final brine TDS and increases SEC. Response surface methodology (RSM) was employed to optimize process performance across multiple criteria, optimizing flux, SEC, recovery, and final brine concentration. The optimal feed flow rate and pressure vary depending on the criteria in the improvement scenarios, underscoring the importance of systematic process improvement. Full article
(This article belongs to the Special Issue Membrane Separation and Water Treatment: Modeling and Application)
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37 pages, 2845 KiB  
Review
Advancing Ceramic Membrane Technology for Sustainable Treatment of Mining Discharge: Challenges and Future Directions
by Seyedeh Laleh Dashtban Kenari, Saviz Mortazavi, Sanaz Mosadeghsedghi, Charbel Atallah and Konstantin Volchek
Membranes 2025, 15(4), 112; https://doi.org/10.3390/membranes15040112 - 3 Apr 2025
Viewed by 247
Abstract
Mining discharge, namely acid mine drainage (AMD), is a significant environmental issue due to mining activities and site-specific factors. These pose challenges in choosing and executing suitable treatment procedures that are both sustainable and effective. Ceramic membranes, with their durability, long lifespan, and [...] Read more.
Mining discharge, namely acid mine drainage (AMD), is a significant environmental issue due to mining activities and site-specific factors. These pose challenges in choosing and executing suitable treatment procedures that are both sustainable and effective. Ceramic membranes, with their durability, long lifespan, and ease of maintenance, are increasingly used in industrial wastewater treatment due to their superior features. This review provides an overview of current remediation techniques for mining effluents, focusing on the use of ceramic membrane technology. It examines pressure-driven ceramic membrane systems like microfiltration, ultrafiltration, and nanofiltration, as well as the potential of vacuum membrane distillation for mine drainage treatment. Research on ceramic membranes in the mining sector is limited due to challenges such as complex effluent composition, low membrane packing density, and poor ion separation efficiency. To assess their effectiveness, this review also considers studies conducted on simulated water. Future research should focus on enhancing capital costs, developing more effective membrane configurations, modifying membrane outer layers, evaluating the long-term stability of the membrane performance, and exploring water recycling during mineral processing. Full article
(This article belongs to the Special Issue Advanced Membranes and Membrane Technologies for Wastewater Treatment)
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16 pages, 4857 KiB  
Article
Integration of Specific Aeration Demand (SAD) into Flux-Step Test for Submerged Membrane Bioreactor
by Albert Galizia, Joaquim Comas, Ignasi Rodríguez-Roda, Gaëtan Blandin and Hèctor Monclús
Membranes 2025, 15(4), 111; https://doi.org/10.3390/membranes15040111 - 3 Apr 2025
Viewed by 373
Abstract
This study proposes a novel methodology to assess fouling that complements the flux-step test (FST) by integrating aeration-step tests (ASTs) to optimise the specific aeration demand (SADm) for ultrafiltration hollow-fibre (UF-HF) submerged membranes in membrane bioreactor (MBR) configurations. Three membranes with distinct manufacturing [...] Read more.
This study proposes a novel methodology to assess fouling that complements the flux-step test (FST) by integrating aeration-step tests (ASTs) to optimise the specific aeration demand (SADm) for ultrafiltration hollow-fibre (UF-HF) submerged membranes in membrane bioreactor (MBR) configurations. Three membranes with distinct manufacturing processes—non-thermal-induced phase separation (NIPS) and thermal-induced phase separation (TIPS)—were evaluated under continuous and intermittent aeration. The AST revealed that the critical SADm has a range of 0.1–0.5 m3·m−2·h−1 for continuous aeration and 0.1–0.2 m3·m−2·h−1 for intermittent aeration. NIPS membranes with homogeneous structures were less prone to fouling under intermittent aeration, while TIPS membranes with a heterogeneous structure exhibited better recovery under continuous aeration, reflecting distinct fouling dynamics. Findings indicate that the FST alone does not fully represent operational conditions, as aeration efficiency is linked to membrane structure and aeration mode. By combining the FST with ASTs, our approach enables tailored fouling control strategies, reducing energy consumption and improving MBR performance. These insights are critical for advancing toward energy-efficient wastewater treatment technologies. Full article
(This article belongs to the Special Issue Membrane Fouling Control: Mechanism, Properties, and Applications)
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22 pages, 5224 KiB  
Article
Impacts of Natural Organic Matter and Dissolved Solids on Fluoride Retention of Polyelectrolyte Multilayer-Based Hollow Fiber Nanofiltration Membranes
by Hussein Abuelgasim, Nada Nasri, Martin Futterlieb, Radhia Souissi, Fouad Souissi, Stefan Panglisch and Ibrahim M. A. ElSherbiny
Membranes 2025, 15(4), 110; https://doi.org/10.3390/membranes15040110 - 2 Apr 2025
Viewed by 389
Abstract
This study examines the effects of natural organic matter (NOM) and dissolved solids on fluoride (F−) retention in polyelectrolyte multilayer-based hollow-fiber nanofiltration membranes (dNF40). Lab-scale filtration experiments were conducted under varying operating conditions (initial salt concentration, NOM concentration, permeate flux, crossflow [...] Read more.
This study examines the effects of natural organic matter (NOM) and dissolved solids on fluoride (F−) retention in polyelectrolyte multilayer-based hollow-fiber nanofiltration membranes (dNF40). Lab-scale filtration experiments were conducted under varying operating conditions (initial salt concentration, NOM concentration, permeate flux, crossflow velocity, and recovery rate). dNF40 membranes exhibited F− retention above 70% ± 1.2 in the absence of NOM and competing ions. However, when filtering synthetic model water (SMW) designed to simulate groundwater contaminated with high total dissolved solids (TDSs) and NOM, F− retention decreased to approximately 60% ± 0.7, which was generally attributed to ion competition. Furthermore, despite limited declines in normalized permeability, the addition of NOM to SMW notably deceased F− retention in the steady state to~20% due to fouling effects. The facilitated transport of the divalent cations Ca2+ and Mg2+ could be observed, as they accumulated in the organic fouling layer. While SO42− retention remained relatively stable, the retention of monovalent anions (NO3−, Cl−, and F−) decreased substantially due to drag effects. Na+ retention improved slightly to maintain electroneutrality. Feed salinity was shown to significantly affect separation efficiency, with PEC layers undergoing swelling and certain structural changes as the ionic strength increased. During batch filtration experiments at varying recovery rates, the retention of monovalent anions further decreased, with F− retention reducing to just ~10% at a 90% recovery rate. This study provides valuable insights into better understanding and optimizing the performance of PEC-based NF membranes across diverse water treatment scenarios. Full article
(This article belongs to the Section Membrane Applications for Water Treatment)
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11 pages, 2284 KiB  
Article
The Nexus Between Sperm Membrane Integrity, Sperm Motility, and DNA Fragmentation
by Alfredo Góngora, Stephen Johnston, Pablo Contreras, Carmen López-Fernández and Jaime Gosálvez
Membranes 2025, 15(4), 109; https://doi.org/10.3390/membranes15040109 - 2 Apr 2025
Viewed by 330
Abstract
This study investigated the interrelationships between sperm plasma membrane integrity, motility, and DNA fragmentation (SDF) to provide a more holistic understanding of male fertility. A total of 1159 ejaculates were analyzed for sperm membrane integrity (% dead spermatozoa), motility (% immotile spermatozoa), and [...] Read more.
This study investigated the interrelationships between sperm plasma membrane integrity, motility, and DNA fragmentation (SDF) to provide a more holistic understanding of male fertility. A total of 1159 ejaculates were analyzed for sperm membrane integrity (% dead spermatozoa), motility (% immotile spermatozoa), and SDF (% sperm with fragmented DNA). The statistical methods included non-parametric correlation analysis and artificial intelligence (AI)-generated cluster analysis to identify patterns based on these three parameters. The results showed a moderate correlation (ρ = 0.65; p < 0.000) between sperm membrane integrity and motility, indicating that immotile sperm were more likely to exhibit membrane damage. A weak correlation (ρ = 0.21; p < 0.000) suggested that DNA damage was largely independent of the other sperm parameters. Cluster analysis identified three main clusters: Cluster 0: high levels of low membrane integrity, immotile sperm, and moderate DNA fragmentation. Cluster 1: moderate membrane integrity and motility but extremely high DNA fragmentation. Cluster 2: the lowest levels of membrane damage, immotile sperm, and DNA fragmentation, indicating overall better sperm quality. The clustering techniques demonstrated their ability to integrate multiple sperm parameters, enabling a more individualized fertility diagnosis and potentially enhancing male infertility assessments. Full article
(This article belongs to the Section Biological Membranes)
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20 pages, 2750 KiB  
Article
Influence of Nanoparticle Content and Cross-Linking Degree on Functional Attributes of Calcium Alginate-ZnO Nanocomposite Wound Dressings
by Sergio Henrique Toledo e Silva, Andrea Cristiane Krause Bierhalz and Ângela Maria Moraes
Membranes 2025, 15(4), 108; https://doi.org/10.3390/membranes15040108 - 1 Apr 2025
Viewed by 274
Abstract
Alginate-ZnO nanoparticles (ZnOnano) composite wound dressing membranes were prepared with two different ZnOnano concentrations (0.03 and 0.20 g ZnO/g sodium alginate) and cross-linked with two different calcium treatments (low and high Ca++concentration) to evaluate the influence of nanoparticle [...] Read more.
Alginate-ZnO nanoparticles (ZnOnano) composite wound dressing membranes were prepared with two different ZnOnano concentrations (0.03 and 0.20 g ZnO/g sodium alginate) and cross-linked with two different calcium treatments (low and high Ca++concentration) to evaluate the influence of nanoparticle content and cross-linking degree on membrane attributes. ZnOnano addition did not significantly alter the mechanical properties, water vapor permeability, swelling degree in water and the alginate amorphous nature of the nanocomposite membranes. The increase in cross-linking degree, on the other hand, altered the microstructure of the membranes, increased the tensile strength and reduced the water vapor permeability of the nanocomposite membranes. The presence of ZnOnano in alginate membranes granted them antibacterial activity in vitro against Pseudomonas aeruginosa and Staphylococcus aureus and substantially increased the absorption capacity in phosphate buffer and fetal bovine serum solutions, validating their potential use as wound dressings. Full article
(This article belongs to the Section Membrane Applications for Other Areas)
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31 pages, 11434 KiB  
Article
Optimization of Carbon Dioxide Utilization: Simulation-Based Analysis of Reverse Water Gas Shift Membrane Reactors
by Putri Permatasari, Manabu Miyamoto, Yasunori Oumi, Yogi Wibisono Budhi, Haroki Madani, Teguh Kurniawan and Shigeyuki Uemiya
Membranes 2025, 15(4), 107; https://doi.org/10.3390/membranes15040107 - 1 Apr 2025
Viewed by 339
Abstract
This study focuses on optimizing the Reverse Water Gas Shift (RWGS) reaction system using a membrane reactor to improve CO2 conversion efficiency. A one-dimensional simulation model was developed using FlexPDE Professional Version 8.01/W64 software to analyze the performance of ZSM-5 membranes integrated [...] Read more.
This study focuses on optimizing the Reverse Water Gas Shift (RWGS) reaction system using a membrane reactor to improve CO2 conversion efficiency. A one-dimensional simulation model was developed using FlexPDE Professional Version 8.01/W64 software to analyze the performance of ZSM-5 membranes integrated with 0.5 wt% Ru-Cu/ZnO/Al2O3 catalysts. The results show that the membrane reactor significantly outperforms the conventional Packed Bed Reactor by achieving higher CO2 conversion (0.61 vs. 0.99 with optimized parameters), especially at lower temperatures, due to its ability to remove H2O and shift the reaction equilibrium selectively. Key operational parameters, including temperature, pressure, and sweep gas flow rate, were optimized to maximize membrane reactor performance. The ZSM-5 membrane showed strong H2O selectivity, with an optimum operating temperature of around 400–600 °C. The problem is that many reactants permeate at higher temperatures. Subsequently, a Half-MPBR design was introduced. This design was able to overcome the reactant permeation problem and increase the conversion. The conversion ratios for PBR, MPBR, and Half-MPBR are 0.71, 0.75, and 0.86, respectively. This work highlights the potential of membrane reactors to overcome the thermodynamic limitations of RWGS reactions and provides valuable insights to advance Carbon Capture and Utilization technologies. Full article
(This article belongs to the Section Membrane Fabrication and Characterization)
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17 pages, 5190 KiB  
Article
Boundary Flow-Induced Membrane Tubulation Under Turgor Pressures
by Hao Xue and Rui Ma
Membranes 2025, 15(4), 106; https://doi.org/10.3390/membranes15040106 - 1 Apr 2025
Viewed by 221
Abstract
During clathrin-mediated endocytosis in yeast cells, a small patch of flat membrane is deformed into a tubular shape. It is generally believed that the tubulation is powered by actin polymerization. However, studies based on quantitative measurement of the actin molecules suggest that they [...] Read more.
During clathrin-mediated endocytosis in yeast cells, a small patch of flat membrane is deformed into a tubular shape. It is generally believed that the tubulation is powered by actin polymerization. However, studies based on quantitative measurement of the actin molecules suggest that they are not sufficient to produce the forces to overcome the high turgor pressure inside of the cell. In this paper, we model the membrane as a viscous 2D fluid with elasticity and study the dynamic membrane deformation powered by a boundary lipid flow under osmotic pressure. We find that in the absence pressure, the lipid flow drives the membrane into a spherical shape or a parachute shape. The shapes over time exhibit self-similarity. The presence of pressure transforms the membrane into a tubular shape that elongates almost linearly with time and the self-similarity between shapes at different times is lost. Furthermore, the width of the tube is found to scale inversely to the cubic root of the pressure, and the tension across the membrane is negative and scales to the cubic root squared of the pressure. Our results demonstrate that boundary flow powered by myosin motors, as a new way to deform the membrane, could be a supplementary mechanism to actin polymerization to drive endocytosis in yeast cells. Full article
(This article belongs to the Special Issue Design Principles and Biomedical Applications of Multifunctional Biological Membranes)
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21 pages, 4489 KiB  
Article
Membrane for Pressure-Driven Separation Prepared with a Method of 3D Printing: Performance in Concentrating Orange Peel Extract
by Priscila Pini Pereira, Isabela Pacola Gonçalves, Luiza C. A. Molina, Roberta Delcolle, Yuliya S. Dzyazko, Carolina Moser Paraiso, Guilherme L. Batista Neto, Alexandre Diório, Angélica Marquetotti Salcedo Vieira and Rosângela Bergamasco
Membranes 2025, 15(4), 105; https://doi.org/10.3390/membranes15040105 - 1 Apr 2025
Viewed by 282
Abstract
3D-printing enables the fabrication of membranes with desired shapes and geometrical parameters. In this study, a membrane for pressure-driven processes was manufactured in a single step using the fused deposition modeling (FDM) technique. The membrane was produced from a mixture of polylactic acid [...] Read more.
3D-printing enables the fabrication of membranes with desired shapes and geometrical parameters. In this study, a membrane for pressure-driven processes was manufactured in a single step using the fused deposition modeling (FDM) technique. The membrane was produced from a mixture of polylactic acid (PLA) with sucrose as a pore-forming agent. Sucrose was removed from the final membrane by washing it with water. The membrane consists of three layers, and this sandwich-like structure ensures its mechanical stability. The material obtained was characterized using SEM and AFM imaging, as well as nitrogen adsorption-desorption and contact angle measurements. The porosity of each layer of the membrane is due to a loose region, which is coated on both sides with a dense film formed during printing. The pores responsible for rejection capability can be found in grooves between the polymer stripes in the dense layer. The membrane exhibits a water permeability of 64 L m−2h−1bar−1, with a molecular weight cut-off of 69 kDa. The PLA membrane can be used for polyphenol concentration, demonstrating a permeability of 2–3.4 L m−2h−1bar−1 and a selectivity towards these compounds of 78–98% at 0.5 bar, with a flux decline ratio of up to 50%. Full article
(This article belongs to the Section Membrane Applications for Other Areas)
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24 pages, 9051 KiB  
Article
Influence of Silane Treatment on CNM/PAC/PVDF Properties and Performance for Water Desalination by VMD
by Samraa R. Khaleel, Salah S. Ibrahim, Alessandra Criscuoli, Alberto Figoli, Dahiru U. Lawal and Qusay F. Alsalhy
Membranes 2025, 15(4), 104; https://doi.org/10.3390/membranes15040104 - 1 Apr 2025
Viewed by 315
Abstract
Vacuum membrane distillation (VMD) is a promising process for water desalination. However, it suffers some obstacles, such as fouling and wetting, due to the inadequate hydrophobicity of the membrane and high vacuum pressure on the permeate side. Therefore, improving surface hydrophobicity and roughness [...] Read more.
Vacuum membrane distillation (VMD) is a promising process for water desalination. However, it suffers some obstacles, such as fouling and wetting, due to the inadequate hydrophobicity of the membrane and high vacuum pressure on the permeate side. Therefore, improving surface hydrophobicity and roughness is important. In this study, the effect of 1H,1H,2H,2H-Perfluorodecyltriethoxysilane (PFTES) on the morphology and performance of CNM/PAC/PVDF membranes at various concentrations was investigated for the first time. Membrane characteristics such as FTIR, XRD, FE-SEM, EDX, contact angle, and hydrophobicity before and after modification were analyzed and tested using VMD for water desalination. The results showed that the membrane coated with 1 wt.% PFTES had a higher permeate flux and lower rejection than the membranes coated with the 2 wt.% PFTES. The 2 wt.% PFTES enhanced the contact angle to 117° and increased the salt rejection above 99.9%, with the permeate flux set to 23.2 L/m2·h and at a 35 g/L NaCl feed solution, 65 °C feed temperature, a 0.6 L/min feed flow rate, and 21 kPa (abs) vacuum pressure. This means that 2 wt.% PFTES-coated PVDF membranes exhibited slightly lower permeate flux with higher hydrophobicity, salt rejection, and stability over long-term operation. These outstanding results indicate the potential of the novel CNM/PAC/PVDF/PFTES membranes for saline water desalination. Moreover, this study presents useful guidance for the enhancement of membrane structures and physical properties in the field of saline water desalination using porous CNM/PAC/PVDF/PFTES membranes. Full article
(This article belongs to the Special Issue Membrane Distillation and Other Membrane-Related Applications for Water Cleaning and Desalination)
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17 pages, 1419 KiB  
Review
DNA Transactions in Bacteria and Membranes: A Place for the Hfq Protein?
by Sylwia Bloch, Richard R. Sinden, Frank Wien, Grzegorz Węgrzyn and Véronique Arluison
Membranes 2025, 15(4), 103; https://doi.org/10.3390/membranes15040103 - 1 Apr 2025
Viewed by 317
Abstract
DNA metabolism consists of crucial processes occurring in all living cells. These processes include various transactions, such as DNA replication, genetic recombination, transposition, mutagenesis, and DNA repair. While it was initially assumed that these processes might occur in the cytoplasm of prokaryotic cells, [...] Read more.
DNA metabolism consists of crucial processes occurring in all living cells. These processes include various transactions, such as DNA replication, genetic recombination, transposition, mutagenesis, and DNA repair. While it was initially assumed that these processes might occur in the cytoplasm of prokaryotic cells, subsequent reports indicated the importance of the cell membrane in various DNA transactions. Furthermore, newly identified factors play significant roles in regulating DNA-related cellular processes. One such factor is the Hfq protein, originally discovered as an RNA chaperone but later shown to be involved in several molecular mechanisms. These include DNA transactions and interaction with the cell membrane. Recent studies have suggested that Hfq plays a role in the regulation of DNA replication, mutagenesis, and recombination. In this narrative review, we will focus on the importance of membranes in DNA transactions and discuss the potential role of Hfq-mediated regulation of these processes in Escherichia coli, where the protein is the best characterized. Special attention is given to the affinity of this small protein for both DNA and membranes, which might help explain some of the findings from recent experiments. Full article
(This article belongs to the Collection Featured Reviews in Membrane Science)
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15 pages, 4706 KiB  
Article
Quaternized Polysulfone as a Solid Polymer Electrolyte Membrane with High Ionic Conductivity for All-Solid-State Zn-Air Batteries
by Luis Javier Salazar-Gastélum, Alejandro Arredondo-Espínola, Sergio Pérez-Sicairos, Lorena Álvarez-Contreras, Noé Arjona and Minerva Guerra-Balcázar
Membranes 2025, 15(4), 102; https://doi.org/10.3390/membranes15040102 - 1 Apr 2025
Viewed by 740
Abstract
Solid polymer electrolytes (SPEs) are gaining attention as viable alternatives to traditional aqueous electrolytes in zinc–air batteries (ZABs), owing to their enhanced performance and stability. In this study, anion-exchange solid polymer electrolytes (A-SPEs) were synthesized via electrophilic aromatic substitution and substitution reactions. Thin [...] Read more.
Solid polymer electrolytes (SPEs) are gaining attention as viable alternatives to traditional aqueous electrolytes in zinc–air batteries (ZABs), owing to their enhanced performance and stability. In this study, anion-exchange solid polymer electrolytes (A-SPEs) were synthesized via electrophilic aromatic substitution and substitution reactions. Thin films were prepared using the solvent casting method and characterized using proton nuclear magnetic resonance (¹H-NMR), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). The ion-exchange capacity (IEC), KOH uptake, ionic conductivity, and battery performance were also obtained by varying the degree of functionalization of the A-SPEs (30 and 120%, denoted as PSf30/PSf120, respectively). The IEC analysis revealed that PSf120 exhibited a higher quantity of functional groups, enhancing its hydroxide conductivity, which reached a value of 22.19 mS cm−1. In addition, PSf120 demonstrated a higher power density (70 vs. 50 mW cm−2) and rechargeability than benchmarked Fumapem FAA-3-50 A-SPE. Postmortem analysis further confirmed the lower formation of ZnO for PSf120, indicating the improved stability and reduced passivation of the zinc electrode. Therefore, this type of A-SPE could improve the performance and rechargeability of all-solid-state ZABs. Full article
(This article belongs to the Special Issue Recent Advances in Polymeric Membranes—Preparation and Applications)
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17 pages, 6340 KiB  
Article
Membrane Remodeling Driven by Shallow Helix Insertions via a Cooperative Mechanism
by Jie Hu and Yiben Fu
Membranes 2025, 15(4), 101; https://doi.org/10.3390/membranes15040101 - 1 Apr 2025
Viewed by 237
Abstract
Helix-membrane interactions are key to membrane deformation and play significant biological roles. However, systematic studies on the mechanisms behind these interactions are limited. This study uses a continuum membrane model to investigate how shallowly inserted helices interact with biological membranes, focusing on membrane [...] Read more.
Helix-membrane interactions are key to membrane deformation and play significant biological roles. However, systematic studies on the mechanisms behind these interactions are limited. This study uses a continuum membrane model to investigate how shallowly inserted helices interact with biological membranes, focusing on membrane deformation and the cooperative effects of multiple helices. Our findings show that even short helices (2 nm in length) can induce anisotropic membrane deformation. Longer helices and deeper insertions result in more significant deformations, and the spatial arrangement of helices affects the nature of these deformations. The perturbation area (PA) and perturbation extent (PE) are quantified to describe membrane deformation, revealing stronger cooperative effects in parallel insertions and more complex deformations in other arrangements. Additionally, membrane properties, such as lipid composition, influence the extent of deformation. In multi-helix systems, we observe local clustering behavior when perturbations are strong enough, with cooperativity varying based on helix length, insertion depth, and membrane composition. This study provides criteria for helix cooperativity, advancing our understanding of helix–membrane interactions and their biological significance in processes like membrane remodeling. Full article
(This article belongs to the Special Issue Design Principles and Biomedical Applications of Multifunctional Biological Membranes)
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18 pages, 3668 KiB  
Article
Hybrid Adsorption–Microfiltration Process for the Pretreatment of Sulfide-Containing Seawater: A Promising Strategy to Mitigate Membrane Fouling
by Ludi Song, Chengyi Dai, Zifei Chai, Mengzhe Cai, Huazhang Li, Sifan Wu, Lin Zhang, Yaqin Wu and Haitao Zhu
Membranes 2025, 15(4), 100; https://doi.org/10.3390/membranes15040100 - 31 Mar 2025
Viewed by 269
Abstract
The presence of dissolved sulfides in feed seawater causes severe elemental sulfur fouling in the reverse osmosis (RO) process. However, current pretreatment methods suffer from large footprint, high energy consumption, and limitations in effluent quality. In this study, adsorption and microfiltration are merged [...] Read more.
The presence of dissolved sulfides in feed seawater causes severe elemental sulfur fouling in the reverse osmosis (RO) process. However, current pretreatment methods suffer from large footprint, high energy consumption, and limitations in effluent quality. In this study, adsorption and microfiltration are merged into a single process for the pretreatment of sulfide-containing seawater. Powdered activated carbon (PAC) was selected for its superior adsorption capacity (14.6-fold) and faster kinetics (3.9-fold) for sulfide removal compared to granular activated carbon. The high surface area and multiple pore structures of PAC facilitate surface and intraparticle diffusion, as well as anion–π conjugation likely occur between PAC and sulfide. Polypropylene microporous membranes, capable of tolerating high PAC dosages, were used in the hybrid process. Long-term pilot tests demonstrated that the effluent (turbidity < 1 NTU and SDI15 ≈ 2.50) met the quality requirements for RO unit feedwater, achieving 100% sulfide removal efficiency over 101 h, with no risk of PAC leakage throughout the entire operation process. The formation of a loose, porous PAC cake layer alleviates membrane fouling and enhances the retention and adsorption of metal(loid)s and sulfide. Moreover, the low permeate flux of the polymeric membranes significantly mitigates filter cake formation. The hybrid system adapts to variations in feedwater quality, making it highly suitable for desalination plants with limited space and budget. These findings offer valuable insights and practical guidance for advancing seawater desalination pretreatment. Full article
(This article belongs to the Section Membrane Applications for Water Treatment)
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15 pages, 2086 KiB  
Article
A Novel Empirical Fractional Approach for Modeling the Clogging of Membrane Filtration During Protein Microfiltration
by Leila Cherifi, Yamina Ammi, Salah Hanini, Mohamed Hentabli, Ouafa Belkacem and Jérôme Harmand
Membranes 2025, 15(4), 99; https://doi.org/10.3390/membranes15040099 - 26 Mar 2025
Viewed by 290
Abstract
This study addresses the pervasive challenge of membrane filtration clogging across various industries. Eight new empirical fractional models are proposed based on the volume accumulation change curve. The effectiveness of these models in predicting material accumulation and characterizing clogging patterns is evaluated. The [...] Read more.
This study addresses the pervasive challenge of membrane filtration clogging across various industries. Eight new empirical fractional models are proposed based on the volume accumulation change curve. The effectiveness of these models in predicting material accumulation and characterizing clogging patterns is evaluated. The models are validated against experimental data, achieving impressive coefficients of determination (R2) between 0.9896 and 0.9997 and relative root mean squared errors (nRMSE) ranging from 0.8674% to 2.9548%. Furthermore, comparing the results with theoretical models of Hermia allows us to relate the empirical models to clogging mechanisms. Full article
(This article belongs to the Section Membrane Fabrication and Characterization)
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21 pages, 5698 KiB  
Review
Water–Energy Nexus: Membrane Engineering Towards a Sustainable Development
by Alessandra Criscuoli
Membranes 2025, 15(4), 98; https://doi.org/10.3390/membranes15040098 - 26 Mar 2025
Viewed by 328
Abstract
Sustainable development is linked to the achievement of several different objectives, as outlined by the 17 Sustainable Development Goals (SDGs) defined by the United Nations. Among them are the production of clean water and the combat of climate change, which is strictly linked [...] Read more.
Sustainable development is linked to the achievement of several different objectives, as outlined by the 17 Sustainable Development Goals (SDGs) defined by the United Nations. Among them are the production of clean water and the combat of climate change, which is strictly linked to the use of fossil fuels as a primary energy source and their related CO2 emissions. Water and energy are strongly interconnected. For instance, when processing water, energy is needed to pump, treat, heat/cool, and deliver water. Membrane operations for water treatment/desalination contribute to the recovery of purified/fresh water and reducing the environmental impact of waste streams. However, to be sustainable, water recovery must not be energy intensive. In this respect, this contribution aims to illustrate the state of the art and perspectives in desalination by reverse osmosis (RO), discussing the various approaches looking to improve the energy efficiency of this process. In particular, the coupling of RO with other membrane operations, like pressure-retarded osmosis (PRO), reverse electrodialysis (RED), and forward osmosis (FO), as well as the osmotic-assisted reverse osmosis (OARO) system, are reported. Moreover, the possibility of coupling a membrane distillation (MD) unit to an RO one to increase the overall freshwater recovery factor and reduce the brine volumes that are disposed is also discussed. Specific emphasis is placed on the strategies being applied to reduce the MD thermal energy demand, so as to couple the production of the blue gold with the fight against climate change. Full article
(This article belongs to the Topic New Advances in Membrane Technology and Its Contribution to Sustainability)
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15 pages, 1820 KiB  
Article
Nickel and Cobalt Recovery from Spent Lithium-Ion Batteries via Electrodialysis Metathesis
by Adam Isaksson, Juan Anaya Garzon, Ida Strandkvist and Lena Sundqvist Öqvist
Membranes 2025, 15(4), 97; https://doi.org/10.3390/membranes15040097 - 25 Mar 2025
Cited by 1 | Viewed by 388
Abstract
Recycling of spent lithium-ion batteries is important due to the increasing demand for electric vehicles and efforts to realize a circular economy. There is a need to develop environmentally friendly processes for the refining of nickel, cobalt, and other metals contained in the [...] Read more.
Recycling of spent lithium-ion batteries is important due to the increasing demand for electric vehicles and efforts to realize a circular economy. There is a need to develop environmentally friendly processes for the refining of nickel, cobalt, and other metals contained in the batteries. Electrodialysis is an appealing method for recycling of battery metals with selective separation and low chemical input. In this study, sodium sulfate was used in an electrodialysis metathesis procedure to sequentially separate EDTA-chelated nickel and cobalt. Replacing hitherto used sulfuric acid with sodium sulfate mitigates membrane fouling caused by precipitation of EDTA. It was possible to separate up to 97.9% of nickel and 96.6% of cobalt at 0.10 M, a 30-times higher concentration than previously reported for electrodialysis of similar solutions. Through the thermally activated persulfate method, new to this application, 99.7% of nickel and 87.0% of cobalt could be precipitated from their EDTA chelates. Impurity behavior during electrodialysis of battery leachates has not previously been described in the literature. It is paramount to remove copper, iron, and phosphorous prior to electrodialysis since they contaminate the nickel product. Aluminum was difficult to remove in the solution purification step and ended up in all electrodialysis products. Full article
(This article belongs to the Special Issue Research on Electrodialytic Processes)
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