Journal Description
Membranes
Membranes
is an international, peer-reviewed, open access journal, published monthly online by MDPI, covers the broad aspects of the science and technology of both biological and non-biological membranes. European Membrane Society (EMS), Membrane Society of Australasia (MSA) and Polish Membrane Society (PTMem) are affiliated with Membranes and their members receive discounts on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Ei Compendex, PubMed, PMC, CAPlus / SciFinder, Inspec, and other databases.
- Journal Rank: JCR - Q2 (Polymer Science) / CiteScore - Q2 (Chemical Engineering (miscellaneous))
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 13.6 days after submission; acceptance to publication is undertaken in 2.8 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
4.2 (2022);
5-Year Impact Factor:
4.3 (2022)
Latest Articles
Characterizing Macroporous Ion Exchange Membrane Adsorbers for Natural Organic Matter (NOM) Removal—Adsorption and Regeneration Behavior
Membranes 2024, 14(6), 124; https://doi.org/10.3390/membranes14060124 - 27 May 2024
Abstract
Addressing the characterization of Natural Organic Matter (NOM) removal by functionalized membranes in water treatment, this study evaluates the effectiveness of two commercial ion-exchange membrane adsorbers: Sartobind® Q (with quaternary amines) and D (with tertiary amines). Using Suwannee River NOM (SRNOM) as
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Addressing the characterization of Natural Organic Matter (NOM) removal by functionalized membranes in water treatment, this study evaluates the effectiveness of two commercial ion-exchange membrane adsorbers: Sartobind® Q (with quaternary amines) and D (with tertiary amines). Using Suwannee River NOM (SRNOM) as a surrogate, Langmuir adsorption isotherms revealed maximum capacities (Qmax) of 2966 ± 153 mg C/m2 and 2888 ± 112 mg C/m2, respectively. Variations in flux from 50 to 500 LMH had a minimal impact on breakthrough times, proving low diffusion limitations. The macroporous (3–5 µm) functionalized cellulose-based membranes exhibited high permeabilities of 10800 L/(h m2 bar). Q maintained positive zeta potential vs. pH, while D’s zeta potential decreased above pH 7 due to amine deprotonation and turning negative above an isoelectric point of 9.1. Regeneration with 0.01 M NaOH achieved over 95% DOC regeneration for Sartobind® D, characterizing reversibility through a pH-swing. Cyclic adsorption showed that Q maintained its capacity with over 99% DOC regeneration, while D required acidic conditioning after the first regeneration cycle to mitigate capacity reduction and re-deprotonate the adsorber. These results have demonstrated the potential suitability of adsorber membranes, designed originally for biotechnological purposes, for the possible removal of disinfection byproduct precursors in drinking water treatment.
Full article
(This article belongs to the Section Membrane Applications)
Open AccessArticle
Pure Hydrogen and Methane Permeation in Carbon-Based Nanoporous Membranes: Adsorption Isotherms and Permeation Experiments
by
Matthis Kurth, Mudassar Javed, Thomas Schliermann, Georg Brösigke, Susanne Kämnitz, Suresh K. Bhatia and Jens-Uwe Repke
Membranes 2024, 14(6), 123; https://doi.org/10.3390/membranes14060123 - 26 May 2024
Abstract
This paper presents the results of adsorption and permeation experiments of hydrogen and methane at elevated temperatures on a carbon-based nanoporous membrane material provided by Fraunhofer IKTS. The adsorption of pure components was measured between 90 °C and 120 °C and pressures up
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This paper presents the results of adsorption and permeation experiments of hydrogen and methane at elevated temperatures on a carbon-based nanoporous membrane material provided by Fraunhofer IKTS. The adsorption of pure components was measured between 90 °C and 120 °C and pressures up to 45. The Langmuir adsorption isotherm shows the best fit for all data points. Compared to available adsorption isotherms of H and CH on carbon, the adsorption on the investigated nanoporous carbon structures is significantly lower. Single-component permeation experiments were conducted on membranes at temperatures up to 220 °C. After combining the experimental results with a Maxwell–Stefan surface diffusion model, Maxwell–Stefan surface diffusion coefficients were calculated. The calculated values are in line with an empirical model and thus can be used in future multi-component modeling approaches in order to better analyze and design a membrane system. The published adsorption data fill a gap in the available adsorption data for CH4 and H2.
Full article
(This article belongs to the Special Issue Inorganic Membranes for Energy and Environmental Applications)
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Open AccessArticle
Effects of Alkaline Cleaning Agents on the Long-Term Performance and Aging of Polyethersulfone Ultrafiltration Membranes Applied for Treatment of Car Wash Wastewater
by
Marek Gryta, Piotr Woźniak and Sylwia Mozia
Membranes 2024, 14(6), 122; https://doi.org/10.3390/membranes14060122 - 24 May 2024
Abstract
The commercial ultrafiltration polyethersulfone (PES) membranes (10 and 100 kDa) blended with polyvinylpyrrolidone (PVP) were applied for the filtration of car wash wastewater. Periodical membrane rinsing with water did not prevent fouling and a decrease in permeate flux was observed. Fouling was reduced
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The commercial ultrafiltration polyethersulfone (PES) membranes (10 and 100 kDa) blended with polyvinylpyrrolidone (PVP) were applied for the filtration of car wash wastewater. Periodical membrane rinsing with water did not prevent fouling and a decrease in permeate flux was observed. Fouling was reduced by washing the membranes with cleaning agents, which are used in car washes to clean wheels and remove insects. In addition to surfactants, these agents contain NaOH, hence the pH value of cleaning solutions was over 11. Long-term contact with such solutions resulted in the removal of PVP from the membrane matrix and an increase in pore size. The PES membranes were soaked in an alkaline solution (pH = 11.5) for 20 months, after which the 200 kDa dextran rejection decreased from 95% to 80%. To compare with the static degradation conditions, 8 weeks of alkaline agent filtration was realized, after which the dextran (200 kDa) rejection decreased below 50%. This indicated that the cross-flow of alkaline agents can accelerate the removal of components building the membrane matrix. Despite membrane degradation, the separation efficiency (the rejection of chemical oxygen demand—COD, turbidity, and surfactants) during the treatment of synthetic car wash wastewater was similar to that obtained for pristine membranes.
Full article
(This article belongs to the Collection New Challenges in Membranes for Water and Wastewater Application)
Open AccessArticle
Anion Exchange Membrane with Pendulous Piperidinium on Twisted All-Carbon Backbone for Fuel Cell
by
Huaqing Zhang, Wanjie Song, Lixuan Sun, Cui Yang, Xin Zhang, Mingyue Wu, Liang Wu, Xiaolin Ge and Tongwen Xu
Membranes 2024, 14(6), 121; https://doi.org/10.3390/membranes14060121 - 23 May 2024
Abstract
As a central component for anion exchange membrane fuel cells (AEMFCs), the anion exchange membrane is now facing the challenge of further improving its conductivity and alkali stability. Herein, a twisted all-carbon backbone is designed by introducing stereo-contorted units with piperidinium groups dangled
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As a central component for anion exchange membrane fuel cells (AEMFCs), the anion exchange membrane is now facing the challenge of further improving its conductivity and alkali stability. Herein, a twisted all-carbon backbone is designed by introducing stereo-contorted units with piperidinium groups dangled at the twisted sites. The rigid and twisted backbone improves the conduction of hydroxide and brings down the squeezing effect of the backbone on piperidine rings. Accordingly, an anion exchange membrane prepared through this method exhibits adapted OH− conductivity, low swelling ratio and excellent alkali stability, even in high alkali concentrations. Further, a fuel cell assembled with a such-prepared membrane can reach a power density of 904.2 mW/cm2 and be capable of continuous operation for over 50 h. These results demonstrate that the designed membrane has good potential for applications in AEMFCs.
Full article
(This article belongs to the Special Issue Ion-Exchange Membranes and Processes, Fourth Edition)
Open AccessArticle
Bead-Containing Superhydrophobic Nanofiber Membrane for Membrane Distillation
by
Md. Eman Talukder, Md. Romon Talukder, Md. Nahid Pervez, Hongchen Song and Vincenzo Naddeo
Membranes 2024, 14(6), 120; https://doi.org/10.3390/membranes14060120 - 23 May 2024
Abstract
This study introduces an innovative approach to enhancing membrane distillation (MD) performance by developing bead-containing superhydrophobic sulfonated polyethersulfone (SPES) nanofibers with S-MWCNTs. By leveraging SPES’s inherent hydrophobicity and thermal stability, combined with a nanostructured fibrous configuration, we engineered beads designed to optimize the
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This study introduces an innovative approach to enhancing membrane distillation (MD) performance by developing bead-containing superhydrophobic sulfonated polyethersulfone (SPES) nanofibers with S-MWCNTs. By leveraging SPES’s inherent hydrophobicity and thermal stability, combined with a nanostructured fibrous configuration, we engineered beads designed to optimize the MD process for water purification applications. Here, oxidized hydrophobic S-MWCNTs were dispersed in a SPES solution at concentrations of 0.5% and 1.0% by weight. These bead membranes are fabricated using a novel electrospinning technique, followed by a post-treatment with the hydrophobic polyfluorinated grafting agent to augment nanofiber membrane surface properties, thereby achieving superhydrophobicity with a water contact angle (WCA) of 145 ± 2° and a higher surface roughness of 512 nm. The enhanced membrane demonstrated a water flux of 87.3 Lm−2 h−1 and achieved nearly 99% salt rejection efficiency at room temperature, using a 3 wt% sodium chloride (NaCl) solution as the feed. The results highlight the potential of superhydrophobic SPES nanofiber beads in revolutionizing MD technology, offering a scalable, efficient, and robust membrane for salt rejection.
Full article
(This article belongs to the Special Issue Advances in Porous Hydrophobic Membrane Materials for Membrane Distillation)
Open AccessEditorial
Membrane Separation Processes in Wastewater and Water Purification, Volume II
by
Alexandre Giacobbo and Andréa Moura Bernardes
Membranes 2024, 14(6), 119; https://doi.org/10.3390/membranes14060119 - 22 May 2024
Abstract
Water is a crucial natural resource, essential for the development of a range of human activities, from agricultural and industrial to domestic; therefore, its availability is associated with a region or country’s economic growth [...]
Full article
(This article belongs to the Special Issue Membrane Separation Process in Wastewater and Water Purification, Volume II)
Open AccessArticle
Cryptotanshinone-Induced Permeabilization of Model Phospholipid Membranes: A Biophysical Study
by
Julia Ortiz, Francisco J. Aranda, José A. Teruel and Antonio Ortiz
Membranes 2024, 14(6), 118; https://doi.org/10.3390/membranes14060118 - 21 May 2024
Abstract
The Danshen terpenoid cryptotanshinone (CPT) is gaining enormous interest in light of its various outstanding biological activities. Among those, CPT has been shown to interact with cell membranes and, for instance, to have antibacterial activity. Several works have shown that CPT alone, or
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The Danshen terpenoid cryptotanshinone (CPT) is gaining enormous interest in light of its various outstanding biological activities. Among those, CPT has been shown to interact with cell membranes and, for instance, to have antibacterial activity. Several works have shown that CPT alone, or in combination with other drugs, can effectively act as an antibiotic against various infectious bacteria. Some authors have related the mechanism underlying this action to CPT–membrane interaction. This work shows that CPT readily partitions into phosphatidylcholine membranes, but there is a limiting capacity of accommodation of ca. 1 mol CPT to 3 mol phospholipid. The addition of CPT to unilamellar liposomes composed of 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) causes membrane permeabilization, as shown by fluorescent probe leakage. This process has been kinetically studied, as well as its modulation by incorporation of phosphatidylethanolamine or phosphatidylglycerol, as a model for pathogenic cell membranes. The thermotropic behavior of 1,2-dimyristoylphosphatidylcholine (DMPC) model membranes is weakly affected by CPT, but the terpenoid causes significant dehydration of the polar region of the bilayer and weak disordering of the acyl chain palisade, as observed in Fourier-transform infrared spectroscopy (FTIR) results. Small-angle X-ray scattering (SAXS) shows that CPT increases DMPC bilayer thickness, which could be due to localization near the phospholipid/water interface. Molecular dynamics (MD) simulations show that the lateral diffusion coefficient of the phospholipid increases with the presence of CPT. CPT extends from the polar head region to the center of the bilayer, being centered between the carbonyl groups and the unsaturated region of the POPC, where there is greater overlap. Interestingly, the free energy profiles of a water molecule crossing the lipid membrane show that the POPC membrane becomes more permeable in the presence of CPT. In summary, our results show that CPT perturbs the physicochemical properties of the phospholipid membrane and compromises its barrier function, which could be of relevance to explain part of its antimicrobial or anticancer activities.
Full article
(This article belongs to the Section Biological Membrane Composition and Structures)
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Open AccessArticle
In Situ-Grown Al2O3 Nanoflowers and Hydrophobic Modification Enable Superhydrophobic SiC Ceramic Membranes for Membrane Distillation
by
Yuqi Song, Kai Miao, Jinxin Liu, Yutang Kang, Dong Zou and Zhaoxiang Zhong
Membranes 2024, 14(5), 117; https://doi.org/10.3390/membranes14050117 - 19 May 2024
Abstract
Membrane distillation (MD) is considered a promising technology for desalination. In the MD process, membrane pores are easily contaminated and wetted, which will degrade the permeate flux and salt rejection of the membrane. In this work, SiC ceramic membranes were used as the
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Membrane distillation (MD) is considered a promising technology for desalination. In the MD process, membrane pores are easily contaminated and wetted, which will degrade the permeate flux and salt rejection of the membrane. In this work, SiC ceramic membranes were used as the supports, and an Al2O3 micro-nano structure was constructed on its surface. The surface energy of Al2O3@SiC micro-nano composite membranes was reduced by organosilane grafting modification. The effective deposition of Al2O3 nanoflowers on the membrane surface increased membrane roughness and enhanced the anti-fouling and anti-wetting properties of the membranes. Simultaneously, the presence of nanoflowers also regulated the pore structures and thus decreased the membrane pore size. In addition, the effects of Al2(SO4)3 concentration and sintering temperature on the surface morphology and performance of the membranes were investigated in detail. It was demonstrated that the water contact angle of the resulting membrane was 152.4°, which was higher than that of the pristine membrane (138.8°). In the treatment of saline water containing 35 g/L of NaCl, the permeate flux was about 11.1 kg⋅m−2⋅h−1 and the salt rejection was above 99.9%. Note that the pristine ceramic membrane cannot be employed for MD due to its larger membrane pore size. This work provides a new method for preparing superhydrophobic ceramic membranes for MD.
Full article
(This article belongs to the Special Issue Advances in Porous Hydrophobic Membrane Materials for Membrane Distillation)
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Open AccessArticle
Enhancing Water Purification by Integrating Titanium Dioxide Nanotubes into Polyethersulfone Membranes for Improved Hydrophilicity and Anti-Fouling Performance
by
Ayesha Bilal, Muhammad Yasin, Faheem Hassan Akhtar, Mazhar Amjad Gilani, Hamad Almohamadi, Mohammad Younas, Azeem Mushtaq, Muhammad Aslam, Mehdi Hassan, Rab Nawaz, Aqsha Aqsha, Jaka Sunarso, Muhammad Roil Bilad and Asim Laeeq Khan
Membranes 2024, 14(5), 116; https://doi.org/10.3390/membranes14050116 (registering DOI) - 17 May 2024
Abstract
Water pollution remains a critical concern, one necessitated by rapidly increasing industrialization and urbanization. Among the various strategies for water purification, membrane technology stands out, with polyethersulfone (PES) often being the material of choice due to its robust mechanical properties, thermal stability, and
[...] Read more.
Water pollution remains a critical concern, one necessitated by rapidly increasing industrialization and urbanization. Among the various strategies for water purification, membrane technology stands out, with polyethersulfone (PES) often being the material of choice due to its robust mechanical properties, thermal stability, and chemical resistance. However, PES-based membranes tend to exhibit low hydrophilicity, leading to reduced flux and poor anti-fouling performance. This study addresses these limitations by incorporating titanium dioxide nanotubes (TiO2NTs) into PES nanofiltration membranes to enhance their hydrophilic properties. The TiO2NTs, characterized through FTIR, XRD, BET, and SEM, were embedded in PES at varying concentrations using a non-solvent induced phase inversion (NIPS) method. The fabricated mixed matrix membranes (MMMs) were subjected to testing for water permeability and solute rejection capabilities. Remarkably, membranes with a 1 wt% TiO2NT loading displayed a significant increase in pure water flux, from 36 to 72 L m2 h−1 bar−1, a 300-fold increase in selectivity compared to the pristine sample, and a dye rejection of 99%. Furthermore, long-term stability tests showed only a slight reduction in permeate flux over a time of 36 h, while dye removal efficiency was maintained, thus confirming the membrane’s stability. Anti-fouling tests revealed a 93% flux recovery ratio, indicating excellent resistance to fouling. These results suggest that the inclusion of TiO2 NTs offers a promising avenue for the development of efficient and stable anti-fouling PES-based membranes for water purification.
Full article
(This article belongs to the Special Issue Membrane-Based Technologies for Water/Wastewater Treatment)
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Open AccessArticle
Revamping of a Full-Scale Membrane Plant for Landfill Leachate Pretreatment Using Partial Nitritation
by
Laura Palli, Francesca Tuci, Letizia Macellaro La Franca, Donatella Fibbi and Riccardo Gori
Membranes 2024, 14(5), 115; https://doi.org/10.3390/membranes14050115 - 14 May 2024
Abstract
This paper describes a case study involving a revamping of a full-scale membrane bioreactor that treats landfill leachate and other liquid wastes. The main change was the introduction of nitritation/denitritation in alternating cycles instead of the classic denitrification/nitrification process, together with the installation
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This paper describes a case study involving a revamping of a full-scale membrane bioreactor that treats landfill leachate and other liquid wastes. The main change was the introduction of nitritation/denitritation in alternating cycles instead of the classic denitrification/nitrification process, together with the installation of fine bubble diffusers, a reduction in the volume of the biological compartment, and an increase in the equalization volume. The most significant results were obtained for the biological compartment, with a decrease in the specific energy consumption of 46.6%. At the same time, the removal efficiency of COD, BOD, and TN substantially remained the same before and after plant revamping, while the removal efficiency of TP increased over the years, reaching an average value of almost 71%. Regarding the ultrafiltration unit, the specific flux (or permeability) was characterized by an increasing trend. At the same time, the specific energy consumption of this section decreased by 9.4%. These results led to the conclusion that the changes introduced with the revamp led to a more stable process, a reduction in membrane fouling, and important energy savings.
Full article
(This article belongs to the Special Issue A Commemorative Special Issue in Honor of Professor Simon Judd)
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Open AccessArticle
The Helix Ring Peptide U11 from the Venom of the Ant, Tetramorium bicarinatum, Acts as a Putative Pore-Forming Toxin
by
Steve Peigneur, Diogo Tibery and Jan Tytgat
Membranes 2024, 14(5), 114; https://doi.org/10.3390/membranes14050114 - 14 May 2024
Abstract
An insect neuroactive helix ring peptide called U11-MYRTX-Tb1a (abbreviated as U11) from the venom of the ant, Tetramorium bicarinatum. U11 is a 34-amino-acid peptide that is claimed to be one of the most paralytic peptides ever reported
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An insect neuroactive helix ring peptide called U11-MYRTX-Tb1a (abbreviated as U11) from the venom of the ant, Tetramorium bicarinatum. U11 is a 34-amino-acid peptide that is claimed to be one of the most paralytic peptides ever reported from ant venoms acting against blowflies and honeybees. The peptide features a compact triangular ring helix structure stabilized by a single disulfide bond, which is a unique three-dimensional scaffold among animal venoms. Pharmacological assays using Drosophila S2 cells have demonstrated that U11 is not cytotoxic but instead suggest that it may modulate potassium channels via the presence of a functional dyad. In our work described here, we have tested this hypothesis by investigating the action of synthetically made U11 on a wide array of voltage-gated K and Na channels since it is well known that these channels play a crucial role in the phenomenon of paralysis. Using the Xenopus laevis oocyte heterologous expression system and voltage clamp, our results have not shown any modulatory effect of 1 μM U11 on the activity of Kv1.1, Kv1.3, Kv1.4, Kv1.5, Shaker IR, Kv4.2, Kv7.1, Kv10.1, Kv11.1 and KQT1, nor on DmNav and BgNav. Instead, 10 μM U11 caused a quick and irreversible cytolytic effect, identical to the cytotoxic effect caused by Apis mellifera venom, which indicates that U11 can act as a pore-forming peptide. Interestingly, the paralytic dose (PD50) on blowflies and honeybees corresponds with the concentration at which U11 displays clear pore-forming activity. In conclusion, our results indicate that the insecticidal and paralytic effects caused by U11 may be explained by the putative pore formation of the peptide.
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(This article belongs to the Collection Feature Papers in Biological Membrane Functions)
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Open AccessArticle
Can Storage Stability and Simulated Gastrointestinal Behavior Change the Cytotoxic Effects of Concentrated Guava Leaves Extract against Human Lung Cancer Cells?
by
Giordana Demaman Arend, Silvani Verruck, Naira Fernanda Zanchett Schneider, Cláudia Maria Oliveira Simões, Marcus Vinícius Tres, Elane Schwinden Prudêncio, José Carlos Cunha Petrus and Katia Rezzadori
Membranes 2024, 14(5), 113; https://doi.org/10.3390/membranes14050113 - 14 May 2024
Abstract
The influence of storage stability and simulated gastrointestinal behavior of different extracts of guava leaves extracts (NC: not concentrated, and C10 and C20: concentrated by nanofiltration) was evaluated based on their total phenolic compound (TPC) contents and antioxidant activity as well as on
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The influence of storage stability and simulated gastrointestinal behavior of different extracts of guava leaves extracts (NC: not concentrated, and C10 and C20: concentrated by nanofiltration) was evaluated based on their total phenolic compound (TPC) contents and antioxidant activity as well as on their cytotoxic effects on A549 and Vero cells. The results showed that C10 and C20 presented high stability for 125 days probably due to their high TPC contents and antioxidant activity. The simulated gastrointestinal behavior modified their TPC contents; however, after all digestion steps, the TPC values were higher than 70%, which means that they were still available to exert their bioactivities. Additionally, the cytotoxic effects of these extracts were evaluated before and after the simulated gastrointestinal behavior or under different storage conditions. C10 presented the best selectivity indices (SI) values (IC50 Vero cells/IC50 A549 cells) at both conditions suggesting that it can be considered a potential extract to be developed as a functional food due to its resistance to the gastrointestinal digestion and storage conditions tested.
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(This article belongs to the Special Issue Innovations in Membrane Technology for Food Applications)
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Open AccessArticle
Mo-BiVO4 Photocatalytically Modified Ceramic Ultrafiltration Membranes for Enhanced Water Treatment Efficiency
by
George V. Theodorakopoulos, Martha Pylarinou, Elias Sakellis, Fotios K. Katsaros, Vlassis Likodimos and George Em. Romanos
Membranes 2024, 14(5), 112; https://doi.org/10.3390/membranes14050112 - 14 May 2024
Abstract
This study highlights the effectiveness of photocatalytically modified ceramic ultrafiltration (UF) membranes in alleviating two major drawbacks of membrane filtration technologies. These are the generation of a highly concentrated retentate effluent as a waste stream and the gradual degradation of the water flux
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This study highlights the effectiveness of photocatalytically modified ceramic ultrafiltration (UF) membranes in alleviating two major drawbacks of membrane filtration technologies. These are the generation of a highly concentrated retentate effluent as a waste stream and the gradual degradation of the water flux through the membrane due to the accumulation of organic pollutants on its surface. The development of two types of novel tubular membranes, featuring photocatalytic Mo-BiVO4 inverse opal coatings, demonstrated a negligible impact on water permeance, ensuring consistent filtration and photocatalytic efficiency and suggesting the potential for maintaining membrane integrity and avoiding the formation of highly concentrated retentate effluents. Morphological analysis revealed well-defined coatings with ordered domains and interconnected macropores, confirming successful synthesis of Mo-BiVO4. Raman spectroscopy and optical studies further elucidated the composition and light absorption properties of the coatings, particularly within the visible region, which is vital for photocatalysis driven by vis-light. Evaluation of the tetracycline removal efficiency presented efficient adsorption onto membrane surfaces with enhanced photocatalytic activity observed under both UV and vis-light. Additionally, vis-light irradiation facilitated significant degradation, showcasing the versatility of the membranes. Total Organic Carbon (TOC) analysis corroborated complete solute elimination or photocatalytic degradation without the production of intermediates, highlighting the potential for complete pollutant removal. Overall, these findings emphasize the promising applications of Mo-BiVO4 photocatalytic membranes in sustainable water treatment and wastewater remediation processes, laying the groundwork for further optimization and scalability in practical water treatment systems.
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(This article belongs to the Special Issue Sustainable Membrane Technologies for Wastewater Treatment)
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Open AccessArticle
Targeted Anthocyanin Enrichment of Cranberry Juice by Electrodialysis with Filtration Membranes: Impact of Filtration Membrane Physicochemical Properties and Predictive Statistical Models
by
Eva Revellat and Laurent Bazinet
Membranes 2024, 14(5), 111; https://doi.org/10.3390/membranes14050111 - 14 May 2024
Abstract
To optimize cranberry juice enrichment, correlation between physicochemical properties of filtration membranes (FM) and anthocyanin migration was investigated during electrodialysis with filtration membranes (EDFM) using redundancy (RDA) and multivariate regression (MRGA) analyses. Six polyether sulfone (PES) and polyvinylidene fluoride (PVDF) membranes with molecular
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To optimize cranberry juice enrichment, correlation between physicochemical properties of filtration membranes (FM) and anthocyanin migration was investigated during electrodialysis with filtration membranes (EDFM) using redundancy (RDA) and multivariate regression (MRGA) analyses. Six polyether sulfone (PES) and polyvinylidene fluoride (PVDF) membranes with molecular weight cut-offs between 150 and 500 kDa, commercially available at large scale, were characterized in terms of nine physicochemical characteristics and used for EDFM. The highest migration of total anthocyanin was obtained with PVDF 250 kDa, with a global migration rate of 3.5 ± 0.4 g/m2·h. RDA showed that two FM properties (mesopore porosity and hydrophilic porosity) were significantly negatively correlated to the anthocyanin’s migration and explained 67.4% of their total variation in migration. Predictive MRGA models were also developed for each anthocyanin based on these significant FM properties. A combination of intermolecular interactions may lead to binding in a cooperative and synergistic mode and hinder the anthocyanin migration.
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(This article belongs to the Special Issue Research on Electrodialytic Processes)
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Open AccessArticle
Towards the Optimization of a Photovoltaic/Membrane Distillation System for the Production of Pure Water
by
Dufei Fang, Damian M. Amiruddin, Imin Kao, Devinder Mahajan, Xuming Chen and Benjamin S. Hsiao
Membranes 2024, 14(5), 110; https://doi.org/10.3390/membranes14050110 - 13 May 2024
Abstract
The production of pure water plays a pivotal role in enabling sustainable green hydrogen production through electrolysis. The current industrial approach for generating pure water relies on energy-intensive techniques such as reverse osmosis. This study unveils a straightforward method to produce pure water,
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The production of pure water plays a pivotal role in enabling sustainable green hydrogen production through electrolysis. The current industrial approach for generating pure water relies on energy-intensive techniques such as reverse osmosis. This study unveils a straightforward method to produce pure water, employing real-world units derived from previously simulated and developed laboratory devices. This demonstrated system is cost-effective and boasts low energy consumption, utilizing membrane distillation (MD) driven by the waste heat harnessed from photovoltaic (PV) panels. In a previous study, modeling simulations were conducted to optimize the multi-layered MD system, serving as a blueprint for the construction of prototype devices with a suitable selection of materials, enabling the construction of field-testable units. The most efficient PV-MD device, featuring evaporation and condensation zones constructed from steel sheets and polytetrafluoroethylene (PTFE) membranes, is capable of yielding high-purity water with conductivity levels below 145 μS with high flux rates.
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(This article belongs to the Collection Feature Papers in Membrane Engineering and Applications)
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Open AccessReview
Impact of Nitrate on the Removal of Pollutants from Water in Reducing Gas-Based Membrane Biofilm Reactors: A Review
by
Zhiheng Zhang, Zhian Huang, Haixiang Li, Dunqiu Wang, Yi Yao and Kun Dong
Membranes 2024, 14(5), 109; https://doi.org/10.3390/membranes14050109 - 9 May 2024
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The membrane biofilm reactor (MBfR) is a novel wastewater treatment technology, garnering attention due to its high gas utilization rate and effective pollutant removal capability. This paper outlines the working mechanism, advantages, and disadvantages of MBfR, and the denitrification pathways, assessing the efficacy
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The membrane biofilm reactor (MBfR) is a novel wastewater treatment technology, garnering attention due to its high gas utilization rate and effective pollutant removal capability. This paper outlines the working mechanism, advantages, and disadvantages of MBfR, and the denitrification pathways, assessing the efficacy of MBfR in removing oxidized pollutants (sulfate (SO4−), perchlorate (ClO4−)), heavy metal ions (chromates (Cr(VI)), selenates (Se(VI))), and organic pollutants (tetracycline (TC), p-chloronitrobenzene (p-CNB)), and delves into the role of related microorganisms. Specifically, through the addition of nitrates (NO3−), this paper analyzes its impact on the removal efficiency of other pollutants and explores the changes in microbial communities. The results of the study show that NO3− inhibits the removal of other pollutants (oxidizing pollutants, heavy metal ions and organic pollutants), etc., in the simultaneous removal of multiple pollutants by MBfR.
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Open AccessArticle
Multifunctional Eco-Friendly Adsorbent Cryogels Based on Xylan Derived from Coffee Residues
by
Valentina Quintero, Johann F. Osma, Ulugbek Azimov and Debora Nabarlatz
Membranes 2024, 14(5), 108; https://doi.org/10.3390/membranes14050108 - 8 May 2024
Abstract
Agricultural and animal farming practices contribute significantly to greenhouse gas (GHG) emissions such as NH3, CH4, CO2, and NOx, causing local environmental concerns involving health risks and water/air pollution. A growing need to capture these
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Agricultural and animal farming practices contribute significantly to greenhouse gas (GHG) emissions such as NH3, CH4, CO2, and NOx, causing local environmental concerns involving health risks and water/air pollution. A growing need to capture these pollutants is leading to the development of new strategies, including the use of solid adsorbents. However, commonly used adsorbent materials often pose toxicity and negative long-term environmental effects. This study aimed to develop responsive eco-friendly cryogels using xylan extracted from coffee parchment, a typical residue from coffee production. The crosslinking in cryogels was accomplished by “freeze-thawing” and subsequent freeze-drying. Cryogels were characterized in terms of morphology by using scanning electron microscopy, porosity, and density by the liquid saturation method and also moisture adsorption and ammonia adsorption capacity. The analysis showed that the porosity in the cryogels remained around 0.62–0.42, while the apparent densities varied from 0.14 g/cm3 to 0.25 g/cm3. The moisture adsorption capacity was the highest at the highest relative humidity level (80%), reaching 0.25–0.43 g of water per gram of sample; the amount of water adsorbed increased when the xylan content in the cryogel increased up to 10% w/v, which was consistent with the hygroscopic nature of xylan. The ammonia adsorption process was modeled accurately by a pseudo-second-order equation, where the maximum adsorption capacity in equilibrium reached 0.047 mg NH3/g when xylan reached 10% w/v in cryogels, indicating a chemisorption process. The cryogels under investigation hold promise for ammonia adsorption applications and GHG separation, offering a sustainable alternative for gas-capturing processes.
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(This article belongs to the Section Membrane Applications)
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Open AccessArticle
Technical Feasibility of Extraction of Freshwater from Produced Water with Combined Forward Osmosis and Nanofiltration
by
Madina Mohamed, Marco Tagliabue and Alberto Tiraferri
Membranes 2024, 14(5), 107; https://doi.org/10.3390/membranes14050107 - 3 May 2024
Abstract
This study assesses the technical feasibility of a forward-osmosis-based system for concentrating produced water and extracting freshwater. Forward osmosis was combined with nanofiltration, the latter system used to restore the initial osmotic pressure of the diluted draw solutions while concurrently obtaining the final
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This study assesses the technical feasibility of a forward-osmosis-based system for concentrating produced water and extracting freshwater. Forward osmosis was combined with nanofiltration, the latter system used to restore the initial osmotic pressure of the diluted draw solutions while concurrently obtaining the final freshwater product. Three draw solutions, namely, MgCl2, NaCl, and C3H5NaO2, were initially tested against a synthetic water mimicking a pretreated produced water effluent having an osmotic pressure equal to 16.3 bar. MgCl2 was thus selected for high-recovery experiments. Different combinations of draw solution osmotic pressure (30, 40, 60, 80, and 120) and draw-to-feed initial volume ratios (1, 1.6, and 2.2) were tested at the laboratory scale, achieving recovery rates between roughly 35% and 70% and water fluxes between 4 and 8 L m−2h−1. One-dimensional, system-wide simulations deploying the analytical FO water flux equation were utilized to validate the experiments, investigate co-current and counter-current configurations, and understand the system potential. The diluted draw solutions were then transferred to nanofiltration to regenerate their original osmotic pressure. There, the highest observed rejection was 96.6% with an average flux of 21 L m−2h−1, when running the system to achieve 100% relative recovery.
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(This article belongs to the Topic Membrane Separation Technology Research)
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Green and Sustainable Forward Osmosis Process for the Concentration of Apple Juice Using Sodium Lactate as Draw Solution
by
Yuhang Zhao, Chang Liu, Jianju Deng, Panpan Zhang, Shiyuan Feng and Yu Chen
Membranes 2024, 14(5), 106; https://doi.org/10.3390/membranes14050106 - 2 May 2024
Abstract
China is the world’s largest producer and exporter of concentrated apple juice (CAJ). However, traditional concentration methods such as vacuum evaporation (VE) and freeze concentration cause the loss of essential nutrients and heat-sensitive components with high energy consumption. A green and effective technique
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China is the world’s largest producer and exporter of concentrated apple juice (CAJ). However, traditional concentration methods such as vacuum evaporation (VE) and freeze concentration cause the loss of essential nutrients and heat-sensitive components with high energy consumption. A green and effective technique is thus desired for juice concentration to improve product quality and sustainability. In this study, a hybrid forward osmosis–membrane distillation (FO–MD) process was explored for the concentration of apple juice using sodium lactate (L-NaLa) as a renewable draw solute. As a result, commercial apple juice could be concentrated up to 65 °Brix by the FO process with an average flux of 2.5 L·m−2·h−1. Most of the nutritional and volatile compounds were well retained in this process, while a significant deterioration in product quality was observed in products obtained by VE concentration. It was also found that membrane fouling in the FO concentration process was reversible, and a periodical UP water flush could remove most of the contaminants on the membrane surface to achieve a flux restoration of more than 95%. In addition, the L-NaLa draw solution could be regenerated by a vacuum membrane distillation (VMD) process with an average flux of around 7.87 L∙m−2∙h−1 for multiple reuse, which further enhanced the long-term sustainability of the hybrid process.
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(This article belongs to the Special Issue Membranes for Food Preservation and Processing)
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Phospholipid Membrane Interactions of Model Ac-WL-X-LL-OH Peptides Investigated by Solid-State Nuclear Magnetic Resonance
by
Nicolai Etwin Alsaker, Øyvind Halskau, Bengt Erik Haug, Nathalie Reuter and Willy Nerdal
Membranes 2024, 14(5), 105; https://doi.org/10.3390/membranes14050105 - 1 May 2024
Abstract
The role of aromatic amino acids in peripheral protein membrane binding has been reported to involve cation–π interactions with choline lipids. In this study, we have investigated the interactions of the model pentapeptide Ac-WL-X-LL-OH (where X = L, Y, F, or W) with
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The role of aromatic amino acids in peripheral protein membrane binding has been reported to involve cation–π interactions with choline lipids. In this study, we have investigated the interactions of the model pentapeptide Ac-WL-X-LL-OH (where X = L, Y, F, or W) with the phospholipid membrane using solid-state NMR. The effect of guest residue X on the peptide-lipid interactome was complementary to the seminal report on the interfacial hydrophobicity scale by Wimley and White. We found that the phospholipids retained a lamellar phase in the presence of each of the peptides with an aromatic X residue, whereas the Leu peptide perturbed the bilayer to an extent where an additional isotropic phase was observed. The solid-state NMR 13C and 31P data provide additional information on the influence of these short peptides on the membrane that has not been previously reported. The magnitude of membrane perturbation was in the order of guest residue X = L > Y~F > W, which is consistent with the relative amino acid interfacial affinity reported by Wimley and White. Further work is, however, required to uncover the behavior of the peptide and localization in the membrane domain due to ambiguity of the 13C NMR data. We have launched efforts in this regard for the objective of better understanding the role of aromatic amino acids in peripheral membrane protein binding.
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(This article belongs to the Special Issue Protein–Lipid Interactions: Recent Studies, Perspectives, and Challenges)
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