Articoli di riviste: "Membranes modèle"

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Boucard, F., e A. Saboni. "Modélisation du transport des solutés neutres à travers des membranes de nanofiltration". Revue des sciences de l'eau 13, n. 4 (12 aprile 2005): 405–19. http://dx.doi.org/10.7202/705400ar.

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L'exclusion engendrée par la présence de membranes de nanofiltration est due à la superposition de plusieurs mécanismes. Aussi, il est important de pouvoir distinguer ces différents modes de transports afin de les comprendre et de proposer des modèles adéquats. Cette étude s'attachera uniquement à la compréhension du transport de solutés neutres à travers des membranes de ce type. Trois sucres, le glucose, le saccharose et le raffinose, ont été utilisés pour caractériser deux membranes organiques fournies par la société Osmonics. Ce travail montre qu'un modèle simple, basé sur la diffusion, tenant compte des conditions hydrodynamiques du module, est en accord avec les résultats obtenus au laboratoire mais également trouvés dans la littérature. Une bonne adéquation entre le modèle et l'expérience est ainsi obtenue, à la fois sur des modules plans et tubulaires, pour des écoulements laminaires et turbulents.

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Malériat, J. P., P. Jaouen, N. Rossignol, J. P. Schlumpf e F. Quemeneur. "Influence de l'adsorption d'alginates sur les propriétés de membranes organiques d'ultra et de microfiltration". Revue des sciences de l'eau 13, n. 3 (12 aprile 2005): 269–87. http://dx.doi.org/10.7202/705394ar.

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Les applications potentielles des cultures de microalgues et cyanobactéries en dépollution d'effluents dans des photobioréacteurs à membrane souffrent de performances limitées par un colmatage de l'élément filtrant dû en grande partie aux exopolysaccharides sécrétés par ces micro-organismes. Cette étude du laboratoire quantifie les effets de l'adsorption de ces polysaccharides sur des membranes organiques d'ultra et microfiltration tangentielle de matériaux et charges de surface différents. L'alginate de sodium est utilisé comme adsorbat modèle. Les membranes propres sont d'abord testées par une mesure de flux à l'eau pure, puis mises en contact avec une solution d'alginate durant un temps choisi. Le flux à l'eau pure des membranes après adsorption est ensuite à nouveau mesuré. La réduction relative du rayon de pore (ZEMAN, 1983) met en évidence l'effet de la mouillabilité et des charges superficielles. L'étude comparée de membranes d'ultra et microfiltration montre que cette réduction relative du rayon de pore augmente avec le seuil de coupure ou le diamètre de pore. L'effet de la concentration révèle aussi que la résistance hydraulique d'adsorption (MATTHIASSON, 1983) à l'équilibre évolue selon l'isotherme de LANGMUIR. Le modèle cinétique traduisant l'évolution de la résistance d'une membrane d'ultrafiltration proposé par BAKLOUTI et al.(1984), amélioré par AIMAR et al. (1988) puis discuté par RUIZ-BEVIÁ et al. (1997), est complété par un nouvel exposant agissant sur le facteur temps. La comparaison des résistances à l'écoulement de membranes de microfiltration avec celle d'une membrane d'ultrafiltration hydrophile neutre permet de dégager des critères de choix pour l'optimisation du fonctionnement d'un photobioréacteur à membrane utilisable en dépollution d'effluents.

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Pelletier, Émilien, e Peter G. C. Campbell. "L’écotoxicologie aquatique - comparaison entre les micropolluants organiques et les métaux : constats actuels et défis pour l’avenir". Revue des sciences de l'eau 21, n. 2 (22 luglio 2008): 173–97. http://dx.doi.org/10.7202/018465ar.

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Résumé Nous explorons dans cette synthèse les forces et les faiblesses de l’écotoxicologie, en nous limitant aux milieux aquatiques. Notre approche consiste à comparer et contraster le comportement des contaminants organiques et inorganiques (métalliques) et à identifier quelques défis pour l’avenir. La prise en charge des contaminants organiques de synthèse se produit le plus souvent par simple diffusion passive au travers d’une membrane cellulaire. Vu la nature lipidique des membranes biologiques, le coefficient de partage octanol-eau (Kow) du contaminant s’avère souvent un bon prédicteur de sa tendance à se bioaccumuler. Par contre, les métaux présents dans le milieu aquatique se trouvent surtout sous des formes hydrophiles et hydratées qui ne peuvent traverser les membranes biologiques par simple diffusion. Leur prise en charge fait alors appel à un transport facilité qui implique des transporteurs protéiques ou canaux transmembranaires. Le coefficient de partage octanol-eau de ces espèces métalliques se révèle inutile comme prédicteur de leur bioaccumulation. Les approches et les modèles prédictifs diffèrent donc grandement entre contaminants métalliques et organiques. Pour les métaux, deux types de modèles sont couramment employés : des modèles d’équilibre (ex. : le « Modèle du Ligand Biotique » ou BLM) et des modèles cinétiques d’accumulation et d’élimination. Dans les deux cas, les paramètres biologiques des modèles sont considérés comme des « constantes » qui ne sont affectées, ni par la qualité de l’eau ambiante (ex. : pH, dureté), ni par une pré-exposition au métal. Or, il y a maintenant dans la littérature scientifique de plus en plus d’indices que les propriétés clés de la surface épithéliale des organismes aquatiques, qui contrôlent l’accumulation et la toxicité des métaux, ne sont pas constantes, ce qui compromet l’application des modèles dans des cas réels d’exposition chronique sur le terrain. Contrairement aux métaux, l’essentiel du comportement environnemental des composés organiques de synthèse est lié à leur capacité de résister à divers mécanismes de dégradation et à leur biodisponibilité pour les organismes aquatiques. Le modèle de la « fugacité » permet de prédire la distribution de composés organiques entre divers compartiments pour un système considéré à l’équilibre mais de nombreuses contraintes chimiques et biologiques interfèrent avec l’utilisation de ce type de modèle. Les cas des hydrocarbures aromatiques polycycliques (HAP) et des organométaux sont utilisés pour illustrer ces contraintes. Parmi les tout nouveaux défis de l’écotoxicologie, nous abordons brièvement le développement de la génomique fonctionnelle et de l’approche écosystémique ainsi que la toute nouvelle problématique environnementale posée par les nanoparticules industrielles. L’avenir de l’écotoxicologie aquatique passe nécessairement par : (1) l’obtention de données de terrain et de laboratoire d’excellente qualité; (2) une compréhension approfondie des mécanismes de toxicité aux niveaux moléculaire et cellulaire; (3) le développement de modèles théoriques et empiriques qui intègrent mieux la réalité physiologique et écologique; (4) le développement d’indicateurs écosystémiques capables de fournir une image globale de la qualité d’un environnement aquatique, quelle que soit sa complexité inhérente.

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Rheinstädter, M. C., e T. Salditt. "La dynamique collective des membranes bicouches de modèle étudié par diffusion inélastique de neutrons". Journal de Physique IV (Proceedings) 130 (novembre 2005): 141–51. http://dx.doi.org/10.1051/jp4:2005130010.

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Hatoum, Maher, Jean François Fabre, Joel Albet, Claire Vialle, Caroline Sablayrolles e Pierre Yves Pontalier. "Intégration de la simulation de l’ingénierie des processus et de l’évaluation du cycle de vie pour la modélisation de l’impact environnemental de la filtration membranaire". MATEC Web of Conferences 407 (2025): 02001. https://doi.org/10.1051/matecconf/202540702001.

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Le développement des procédés de bioraffinerie nécessite des outils d’éco-conception efficaces afin de démontrer leur réel intérêt écologique tout en minimisant le temps d’acquisition des données permettant l’extrapolation industrielle. L’objet de cet article concerne un de ces outil combinant l’ingénierie des systèmes de procédés (ISP) avec la méthodologie de l’analyse de cycle de vie (ACV) afin d’optimiser un procédé ou une opération unitaire en tenant compte des performances techniques et environnementales. En effet, l’ISP ne permet pas la simulation de toutes les opérations unitaires impliquées dans les procédés de bioraffinerie, comme l’ultrafiltration. Cette étude démontre les avantages du couplage de la simulation de l’ultrafiltration avec l’ACV, en utilisant les logiciel ProsimPlus© et SimaPro©. Un modèle d’ultrafiltration a été développé dans ProsimPlus© afin de simuler l’impact des conditions opératoires sur le flux de perméat en fonction du seuil de coupure des membranes. Les paramètres de ce modèle (α et β) ont été identifiés à partir de résultats expérimentaux de filtration de composés phénoliques avec une membrane comprise entre 5 et 100 kDa, avec une validation montrant une incertitude inférieure à 25%. Ces paramètres ont été utilisés pour modéliser les performances de filtration sous différents types de colmatage, puis la simulation a permis l’évaluation environnementales de chaque condition avec SimaPro©. Les résultats indiquent que réduire l’impact environnemental nécessite de diminuer la surface de filtration. L’ACV identifie également l’étape de nettoyage comme le principal point chaud environnemental et montre qu’en présence de polarisation de concentration, l’impact de la consommation d’énergie est aussi important que celui de la surface de la membrane.

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Podbilewicz, Benjamin. "Membrane fusion as a morphogenetic force in nematode development". Nematology 2, n. 1 (2000): 99–111. http://dx.doi.org/10.1163/156854100508818.

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AbstractIn Caenorhabditis elegans almost all the epithelial cells fuse to form permanent syncytia. Cells in the vulva and hypodermis fuse autonomously to produce ring shaped cells with defined structures and functions. Analysis of temporal and spatial sequence of events together with ultrastructural characterisation of cell fusion intermediates show that fusion pores in specific domains of the membranes dilate and subsequently vesicles are formed. The fusomorphogenetic hypothesis states that these vesicles are targeted to different domains of the plasma membrane where they fuse, thereby causing changes in cell shape. It is proposed that cell fusion and polarised membrane recycling are involved in the formation of ring cells. Fusomorphogenesis is a working model to investigate the forces that drive pattern formation and generate diversity of developmental mechanisms in nematodes. Chez Caenorhabditis elegans, presque toutes les cellules épithéliales fusionnent pour former des syncytia permanents. Les cellules de la vulve et de l’hypoderme fusionnent de façon autonome et produisent des cellules en forme d’anneau avec des structures et des fonctions définies. L’analyse de la séquence temporelle et spatiale des événements, alliée à la caractérisation ultrastructurale des intermédiaires de fusion cellulaire, montre que des pores de fusion se dilatent dans des domaines membranaires spécifiques et que des vésicules sont par la suite formées. L’hypothèse fusomorphogénétique suggère que ces vésicules sont ciblées vers des domaines différents de la membrane plasmique, ou elles fusionnent, provoquant ainsi des changements de forme cellulaire. Il est proposé que la fusion cellulaire et le recyclage polarisé de membranes soient considérés comme impliqués dans la formation des cellules en anneau. La fusomorphogénèse est un guide de travail pour étudier les forces qui entraînent la formation d’un modèle spatial et engendrent la diversité des mécanismes de développement chez les nématodes.

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Schaetzel, Pierre, e Bernard Auclair. "Confrontation de l'équation de nernst-planck de diffusion-convection (dans le modèle homogène) avec les résultats experimentaux obtenus sur plusieurs membranes échangeuses d'ions". European Polymer Journal 24, n. 8 (gennaio 1988): 719–22. http://dx.doi.org/10.1016/0014-3057(88)90004-3.

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Huang, Jian Ping, Yu Min Shao, Li Li Liu e Chun Yan Ma. "Comparative Study on Anti-Fouling Properties and Application of Two PVDF Blend Membranes in Wastewater Treatment". Advanced Materials Research 550-553 (luglio 2012): 2164–69. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.2164.

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The filtration experiments of two PVDF blending membranes were performed. The critical fluxes of PVDF/PMMA and PVDF/TPU blend membranes were measured by the flux-step method. Then tubular membrane module PVDF/PMMA and PVDF/TPU were used to treat alcohol wastewater. The anti-fouling properties of PVDF/TPU membrane module were better than those of PVDF/PMMA membrane module. The critical fluxes of PVDF/PMMA and PVDF/TPU membrane modules were 24 L/(m2∙h) and 22 L/(m2∙h), respectively. In the alcohol wastewater treatment, TMP and SJ of the tested membranes remained stable during this period and membrane module B was more stable than membrane module A. The CODCr removal rates of two membrane modules reached 48% and 58%, respectively. And the UV254removal rates were 18% and 19%, respectively. Both the turbidity removal efficiency were more than 97% and the average effluent values were below 0.10NTU.

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Seshimo, Masahiro, Hiromi Urai, Kazuaki Sasa, Hitoshi Nishino, Yuichiro Yamaguchi, Ryoichi Nishida e Shin-ichi Nakao. "Bench-Scale Membrane Reactor for Methylcyclohexane Dehydrogenation Using Silica Membrane Module". Membranes 11, n. 5 (29 aprile 2021): 326. http://dx.doi.org/10.3390/membranes11050326.

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Methylcyclohexane-toluene system is one of the most promising methods for hydrogen transport/storage. The methylcyclohexane dehydrogenation can be exceeded by the equilibrium conversion using membrane reactor. However, the modularization of the membrane reactor and manufacturing longer silica membranes than 100 mm are little developed. Herein, we have developed silica membrane with practical length by a counter-diffusion chemical vapor deposition method, and membrane reactor module bundled multiple silica membranes. The developed 500 mm-length silica membrane had high hydrogen permselective performance (H2 permeance > 1 × 10−6 mol m−2 s−1 Pa−1, H2/SF6 selectivity > 10,000). In addition, we successfully demonstrated effective methylcyclohexane dehydrogenation using a flange-type membrane reactor module, which was installed with 6 silica membranes. The results indicated that conversion of methylcyclohexane was around 85% at 573 K, whereas the equilibrium conversion was 42%.

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Zhu, Xue Feng, Ming Yuan Zhou, Zhi Wei Wang, Wen Yi Yuan e Jie Guan. "Study on the Membrane Fouling of the Process of Using Two Layer Flat-Sheet Membrane for Sludge Thickening and Water Reuse". Applied Mechanics and Materials 768 (giugno 2015): 467–75. http://dx.doi.org/10.4028/www.scientific.net/amm.768.467.

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In this paper, the critical flux was applied to represent the tendency of membrane fouling. The response surface model was used to study different factors, such as sludge concentration, space between membranes and aeration rate, affecting membrane fouling of the upper and lower layer membrane module. It was found that the model is fitting and significant, moreover, the sludge concentration, space between membranes and aeration rate has a significant impact on the upper and lower membrane fouling. Meanwhile, it was also observed that the critical flux of both upper and lower layer membrane module sharply decreased with the increase of sludge concentration. However, the different variation tendency of membrane fouling between upper and lower layer membrane module was detected due to the change of space between membranes and aeration rate, when it was under different sludge concentrations. Finally, optimum operating parameters under different sludge concentration simulated by response surface model were successfully applied to the process of using flat-sheet membrane for four-stage sludge thickening.

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Jareonsri, L., S. Nawalertpanya e W. Jantaporn. "Preparation and Characterization of Novel Membrane from Waste Polyethylene terephthalate and Bio-based Polymer". IOP Conference Series: Materials Science and Engineering 1280, n. 1 (1 aprile 2023): 012010. http://dx.doi.org/10.1088/1757-899x/1280/1/012010.

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Abstract A large amount of post-consumer Polyethylene terephthalate (PET) bottle waste could be recycled for downstream products. In this work, used PET bottles were utilized as a raw material to develop environmentally-friendly ultrafiltration membranes by phase inversion technique. Poly(ethylene-2,5-furandicarboxylate) (PEF), prepared from a sustainable bio-based monomer, 2,5-furandicarboxylic acid (FDCA), was blended into rPET matrix to improve the mechanical properties of the membrane. Ethanol was also used as a non-solvent in a coagulation bath and polyethylene glycol (PEG) with a molecular weight of 400 Da was added as a hydrophilic additive. The effects of PEF and PEG incorporation to waste PET-based membranes have been thoroughly studied. The morphology of obtained membrane was investigated using Scanning Electron Microscopy (SEM). The membrane’s permeation and resistance were tested using a pressure-driven dead-end membrane module. The result revealed that adding PEF increased the roughness of the membrane surface, which lowered the flux recovery ratio and rejection performance. However, the filtration performance and the membrane resistance could be improved by adjusting the content of the PEG additive.

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Arahman, Nasrul, Sri Mulyati, Afrillia Fahrina, Syawaliah Muchtar, Mukramah Yusuf, Ryosuke Takagi, Hideto Matsuyama, Nik Abdul Hadi Nordin e Muhammad Roil Bilad. "Improving Water Permeability of Hydrophilic PVDF Membrane Prepared via Blending with Organic and Inorganic Additives for Humic Acid Separation". Molecules 24, n. 22 (13 novembre 2019): 4099. http://dx.doi.org/10.3390/molecules24224099.

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The removal of impurities from water or wastewater by the membrane filtration process has become more reliable due to good hydraulic performance and high permeate quality. The filterability of the membrane can be improved by having a material with a specific pore structure and good hydrophilic properties. This work aims at preparing a polyvinylidene fluoride (PVDF) membrane incorporated with phospholipid in the form of a 2-methacryloyloxyethyl phosphorylcholine, polymeric additive in the form of polyvinylpyrrolidone, and its combination with inorganic nanosilica from a renewable source derived from bagasse. The resulting membrane morphologies were analyzed by using scanning electron microscopy. Furthermore, atomic force microscopy was performed to analyze the membrane surface roughness. The chemical compositions of the resulting membranes were identified using Fourier transform infrared. A lab-scale cross-flow filtration system module was used to evaluate the membrane’s hydraulic and separation performance by the filtration of humic acid (HA) solution as the model contaminant. Results showed that the additives improved the membrane surface hydrophilicity. All modified membranes also showed up to five times higher water permeability than the pristine PVDF, thanks to the improved structure. Additionally, all membrane samples showed HA rejections of 75–90%.

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Da Conceicao, Marcos, Leo Nemetz, Joanna Rivero, Katherine Hornbostel e Glenn Lipscomb. "Gas Separation Membrane Module Modeling: A Comprehensive Review". Membranes 13, n. 7 (30 giugno 2023): 639. http://dx.doi.org/10.3390/membranes13070639.

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Membrane gas separation processes have been developed for diverse gas separation applications that include nitrogen production from air and CO2 capture from point sources. Membrane process design requires the development of stable and robust mathematical models that can accurately quantify the performance of the membrane modules used in the process. The literature related to modeling membrane gas separation modules and model use in membrane gas separation process simulators is reviewed in this paper. A membrane-module-modeling checklist is proposed to guide modeling efforts for the research and development of new gas separation membranes.

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Nalatambi, S., K. S. Oh e L. W. Yoon. "Fabrication technique of composite chitosan/alginate membrane module for greywater treatment". Journal of Physics: Conference Series 2120, n. 1 (1 dicembre 2021): 012037. http://dx.doi.org/10.1088/1742-6596/2120/1/012037.

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Abstract A novel chitosan/alginate composite membrane is proposed for the application of greywater treatment. In particular, the effect of stirring speed of mixing chitosan and alginate solution was investigated in this study. The study revealed that 150CSAL and 210CSAL membranes swell significantly compared to CS membrane due to the porous structure of composite membrane. The FTIR spectra revealed that the mixing speed has no influence in terms of molecular interaction between CS and AL due to fixed CS and AL concentrations used in this study. On the other hand, the complexation of AL with CS made outstanding improvement to the dense structure of CS where 180CSAL membrane has UP water flux as high as 90 L/m2h at 2 bar. All membranes have the capability to remove the pollutants present in GW and the COD removal was further improved up to 7% using CSAL membranes. In addition, increasing mixing speed improved the pathogen removal efficiency compared to CS membrane. The treated GW met the non-potable GW reuse standard for turbidity<5 NTU and TSS<20 mg/L. To summarize, the proposed fabrication technique on CSAL membrane showed improved characteristics to CS membrane and has significant performance on GW treatment.

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Lim, Joowan, Kwang Pyo Son, Seung Mo Kang, Hyeongrak Cho, Sangho Lee, Seung-Hyun Kim e Pyung-Kyu Park. "Restoration of the Performance of Membranes Fouled and Wetted in a Pilot-scale Membrane Distillation Process". Journal of Korean Society of Environmental Engineers 46, n. 11 (1 dicembre 2024): 676–86. http://dx.doi.org/10.4491/ksee.2024.46.11.676.

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Objectives : The fouling and wetting of membranes in membrane distillation processes can significantly reduce membrane performance, thereby affecting overall process efficiency. The purpose of this study is to develop methods for restoring the performance of membranes used in a membrane distillation pilot plant operated in the Middle East by testing and optimizing various cleaning methods. This aims to maintain the long-term performance and improve the operational efficiency of the pilot plant through the reuse of restored membranes.Methods : To analyze the main fouling substances on the hollow fiber membranes collected from a module operated in a pilot plant, FTIR, XRD, and SEM analysis techniques were employed. A lab-scale module was fabricated using the collected membranes, and cleaning methods were applied. Citric acid was used for cleaning to restore membrane performance, which was evaluated by measuring water permeability and conductivity before and after cleaning.Results and Discussion : FTIR and XRD analyses revealed that the main fouling substances on the membranes used in the pilot plant were NaCl, CaCO<sub>3</sub>, and CaSO<sub>4</sub>. SEM and ICP analyses confirmed that the membranes near the feed inlet of the module experienced severer fouling compared to those near the outlet. The cleaning method involving pump circulation after inducing artificial wetting was found to be the most effective for restoring membrane performance. Notably, when a high concentration of citric acid was used, almost all fouling substances on the membrane surface were removed, restoring membrane performance to nearly its original state.Conclusion : The cleaning method involving artificial wetting followed by pump circulation was determined to be the optimal method for successfully restoring the performance of membranes fouled and wetted in membrane distillation processes.

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Voitik, O. L., K. I. Delendik e N. V. Kolyago. "Gas separation processes in a diffusion module based on anodic aluminum oxide membrane elements". Doklady of the National Academy of Sciences of Belarus 65, n. 6 (26 dicembre 2021): 749–54. http://dx.doi.org/10.29235/1561-8323-2021-65-6-749-754.

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Anodic alumina membranes with an ordered microstructure have been synthesized and investigated. It was found that Knudsen diffusion is the predominant mechanism for gas penetration through the obtained membranes. The technology made it possible to obtain porous membranes with specified structural characteristics for the separation of gas mixtures. Designs of a diffusion element and a gas separation module based on membranes made of anodic aluminum oxide have been developed, and the features of mass transfer under various operating conditions have been studied. The membrane module without recirculation made it possible to concentrate the heavy component from the model helium-methane mixture (99 % / 1 %) up to 18 %. The membrane module with recirculation made it possible to concentrate a light component from a model helium-methane mixture (1 % / 99 %) up to 40 %.

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Keucken, A., Y. Wang, K. H. Tng, G. L. Leslie, Kenneth M. Persson, Stephan J. Köhler e Tom Spanjer. "Evaluation of novel hollow fibre membranes for NOM removal by advanced membrane autopsy". Water Supply 16, n. 3 (26 novembre 2015): 628–40. http://dx.doi.org/10.2166/ws.2015.170.

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A full-scale inside out hollow fibre membrane module was operated in a pilot-scale water treatment plant in Sweden for a period of 12 months from August 2013 to July 2014. Liquid chromatography– organic carbon detection (LC-OCD) chromatogram indicated the membranes could effectively remove 86% of dissolved organic carbon and 92% of humic substances from the feedwater. Routine cleaning-in-place was conducted to remove any fouling material accumulated on the membranes. Autopsy of the aged membrane samples after 12 months’ operation suggested no significant changes were detected for the membrane samples obtained from the top, middle and bottom sections of the membrane module and were similar to the virgin membrane sample.

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Mesquita, Cristiane Raquel Sousa, Abdul Orlando Cárdenas Gómez, Carolina Palma Naveira Cotta e Renato Machado Cotta. "Comparison of Different Polymeric Membranes in Direct Contact Membrane Distillation and Air Gap Membrane Distillation Configurations". Membranes 15, n. 3 (13 marzo 2025): 91. https://doi.org/10.3390/membranes15030091.

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Membrane distillation (MD) is an evolving thermal separation technique most frequently aimed at water desalination, compatible with low-grade heat sources such as waste heat from thermal engines, solar collectors, and high-concentration photovoltaic panels. This study presents a comprehensive theoretical–experimental evaluation of three commercial membranes of different materials (PE, PVDF, and PTFE), tested for two distinct MD modules—a Direct Contact Membrane Distillation (DCMD) module and an Air Gap Membrane Distillation (AGMD) module—analyzing the impact of key operational parameters on the performance of the individual membranes in each configuration. The results showed that increasing the feed saline concentration from 7 g/L to 70 g/L led to distillate flux reductions of 12.2% in the DCMD module and 42.9% in the AGMD one, averaged over the whole set of experiments. The increase in feed temperature from 65 °C to 85 °C resulted in distillate fluxes up to 2.36 times higher in the DCMD module and 2.70 times higher in the AGMD one. The PE-made membrane demonstrated the highest distillate fluxes, while the PVDF and PTFE membranes exhibited superior performance under high-salinity conditions in the AGMD module. Membranes with high contact angles, such as PTFE with 143.4°, performed better under high salinity conditions. Variations in operational parameters, such as flow rate and temperature, markedly affect the temperature and concentration polarization effects. The analyses underscored the necessity of a careful selection of membrane type for each distillation configuration by the specific characteristics of the process and its operational conditions. In addition to experimental findings, the proposed heat and mass transfer-reduced model showed good agreement with experimental data, with deviations within ±15%, effectively capturing the influence of operational parameters. Theoretical predictions showed good agreement with experimental data, confirming the model’s validity, which can be applied to optimization methodologies to improve the membrane distillation process.

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Goh, Li May, Zhiwei Thong, Weikun Paul Li, Shu Ting Ooi, Farhanah Esa, Kok Seng Ng, Adil Dhalla e Chakravarthy Gudipati. "Development and Industrial-Scale Fabrication of Next-Generation Low-Energy Membranes for Desalination". Membranes 12, n. 5 (22 maggio 2022): 540. http://dx.doi.org/10.3390/membranes12050540.

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Spiral-wound modules have been the most common configuration of packing flat-sheet membranes since the early development of polyamide (PA) membranes for water treatment applications. Conventional spiral-wound modules (SWMs) for desalination applications typically consist of several leaf sets, with each leaf set comprising feed spacers, membranes, and a permeate carrier (PC) wrapped around a permeate-collecting tube. The membrane area that can be packed into a given module diameter is limited by the overall leaf set thickness, restricting module productivity for a given membrane permeability. We describe here a novel industrial-scale method for successfully coating the polysulfone (PSf) ultrafiltration (UF) support layer directly onto a permeate carrier, instead of conventional non-woven fabric, as a precursor to the polyamide TFC coating, resulting in twofold benefits: (a) drastically simplifying the membrane fabrication process by eliminating the use of non-woven fabric and (b) increasing the throughput of each membrane module by facilitating the packing of a larger membrane area in a standard module housing. By combining the permeate carrier and membrane into a single sheet, the need for the non-woven support layer was eliminated, leading to a significantly reduced leaf set thickness, enabling a much larger membrane area to be packed in a given volume, leading to lower energy consumption per cubic meter of produced water. Molecular-weight cutoff (MWCO) values in the range of 36–96 kDa were found to be dependent on PC thickness and material. Nevertheless, the reinforced membranes were successfully fabricated with a ~9% reduction in membrane leaf thickness compared to a conventional membrane. Preliminary trials of coating a thin-film composite PA layer resulted in defect-free reverse osmosis (RO) membranes with a salt rejection of 94% and a flux of 40 L m−2 h−1 when tested against a 2000 mg/L NaCl feed solution at an operating pressure of 15 bar. Results from the testing of the 1812 and 2514 elements validated the novel concept and paved the way for further improvements towards full-scale RO membranes with the potential to be the next low-energy workhorse of the water industry.

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20

Szerencsés, Sz Gy, S. Beszédes, Zs László, G. Veréb, D. Szalay, Zs Hovorkáné Horváth, C. Hodúr, G. Rákhely e Sz Kertész. "Assessment of vibration amplitude and transmembrane pressure on vibratory shear enhanced membrane filtration for treating dairy wastewater". Acta Alimentaria 50, n. 1 (5 marzo 2021): 42–53. http://dx.doi.org/10.1556/066.2020.00123.

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AbstractIn this study, statistical analysis was performed to investigate the influence of operational parameters based on experimental results. The research aimed to know whether a long-term discontinuous module vibration operation is possible without adversely affecting filtration efficiency. Polymer membranes were compared by surface characteristics with contact angle measurements and selected for further membrane filtration experiments for dairy wastewater treatment. The effect of the main operational parameters, membrane module vibration amplitude (Avibr.) and transmembrane pressure (TMP), was investigated using a vibratory shear enhanced processing (VSEP) module with ultrafiltration (UF) and nanofiltration (NF) membranes. Components of the permeates, including chemical oxygen demand (COD), were measured, and membrane rejections were calculated to compare with threshold limit values. The results suggest that proper combination of Avibr. and TMP could mitigate membrane fouling. However, discontinuous module vibration resulted in more clogged membrane with lower fluxes, but slightly higher rejections. We conclude that investigating the significance of operational parameters is necessary for a wider, more energy and environment-friendly application in wastewater treatment.

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21

Alhathal Alanezi, Adnan, H. Abdallah, E. El-Zanati, Adnan Ahmad e Adel O. Sharif. "Performance Investigation of O-Ring Vacuum Membrane Distillation Module for Water Desalination". Journal of Chemistry 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/9378460.

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A new O-ring flat sheet membrane module design was used to investigate the performance of Vacuum Membrane Distillation (VMD) for water desalination using two commercial polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) flat sheet hydrophobic membranes. The design of the membrane module proved its applicability for achieving a high heat transfer coefficient of the order of 103 (W/m2 K) and a high Reynolds number (Re). VMD experiments were conducted to measure the heat and mass transfer coefficients within the membrane module. The effects of the process parameters, such as the feed temperature, feed flow rate, vacuum degree, and feed concentration, on the permeate flux have been investigated. The feed temperature, feed flow rate, and vacuum degree play an important role in enhancing the performance of the VMD process; therefore, optimizing all of these parameters is the best way to achieve a high permeate flux. The PTFE membrane showed better performance than the PVDF membrane in VMD desalination. The obtained water flux is relatively high compared to that reported in the literature, reaching 43.8 and 52.6 (kg/m2 h) for PVDF and PTFE, respectively. The salt rejection of NaCl was higher than 99% for both membranes.

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22

Tomczak, Wirginia, e Marek Gryta. "Membrane Distillation of Saline Water Contaminated with Oil and Surfactants". Membranes 11, n. 12 (17 dicembre 2021): 988. http://dx.doi.org/10.3390/membranes11120988.

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Abstract (sommario):

Application of the membrane distillation (MD) process for the treatment of high-salinity solutions contaminated with oil and surfactants represents an interesting area of research. Therefore, the aim of this study is to investigate the effect of low-concentration surfactants in oil-contaminated high-salinity solutions on the MD process efficiency. For this purpose, hydrophobic capillary polypropylene (PP) membranes were tested during the long-term MD studies. Baltic Sea water and concentrated NaCl solutions were used as a feed. The feed water was contaminated with oil collected from bilge water and sodium dodecyl sulphate (SDS). It has been demonstrated that PP membranes were non-wetted during the separation of pure NaCl solutions over 960 h of the module exploitation. The presence of oil (100–150 mg/L) in concentrated NaCl solutions caused the adsorption of oil on the membranes surface and a decrease in the permeate flux of 30%. In turn, the presence of SDS (1.5–2.5 mg/L) in the oil-contaminated high-salinity solutions slightly accelerated the phenomenon of membrane wetting. The partial pores’ wetting accelerated the internal scaling and affected degradation of the membrane’s structure. Undoubtedly, the results obtained in the present study may have important implications for understanding the effect of low-concentration SDS on MD process efficiency.

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23

Ando, Hideaki, e Hiroshi Hamada. "High.density Membrane Module for MBR". MEMBRANE 47, n. 3 (2022): 177–80. http://dx.doi.org/10.5360/membrane.47.177.

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24

Gryta, Marek. "Capillary Polypropylene Membranes for Membrane Distillation". Fibers 7, n. 1 (20 dicembre 2018): 1. http://dx.doi.org/10.3390/fib7010001.

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Abstract (sommario):

Only nonwetted porous membranes can be used in membrane distillation. The possibility of application in this process the capillary polypropylene membranes manufactured by thermally-induced phase separation was studied. The performance of a few types of membranes available commercially was presented. The resistance of the membranes to wetting was tested in the continuous process of water desalination. These studies were carried out for 1000 h without module cleaning. The presence of scaling layer on the membranes surface was confirmed by Scanning Electron Microscope observations. Both the permeate flux and distillate conductivity were almost not varied after the studied period of time, what indicates that the used membranes maintained their nonwettability, and the negative influence of scaling was limited. The role of surface porosity on the pore wetting and influence of membrane wettability on the quality of the distillate obtained were discussed.

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25

Neto, Guilherme Luiz Oliveira, Nívea Gomes Nascimento de Oliveira, Francisco Alves Batista, Gustavo Henrique de Almeida Barbalho, Anderson Melchiades Vasconcelos da Silva, Lucas Pereira Castanheira Nascimento, Severino Rodrigues de Farias Neto e Antonio Gilson Barbosa de Lima. "Water-Oil Separation Process Using a Porous Ceramic Membrane Module: An Investigation by CFD". Defect and Diffusion Forum 407 (marzo 2021): 22–30. http://dx.doi.org/10.4028/www.scientific.net/ddf.407.22.

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Abstract (sommario):

Environmental concern has encouraged development related to polluted water treatment. Produced water originated from oil exploration has been submitted to different separation processes such as settling tanks, floaters, two-phase and three-phase separators, hydrocyclones, and membranes. On the use of membranes, the goal is to separate soluble components from solutions based on the size, charge, shape, and molecular interactions between the solute and membrane surface. In the present work, a numerical study was developed on the oil-water mixture separation process using a porous ceramic membrane module. The mathematical model used in this research is composed of mass and momentum conservation equations coupled to Darcy ́s law and SST k-ω turbulence model. Simulations were carried out employing the Ansys CFX commercial software. Results of the pressure, velocity, oil concentration distribution inside the device and membrane are presented and discussed. The results showed that the geometric aspects of the proposed microfiltration module and the membrane distribution within the separation module had a significant influence on the hydrodynamic flow leading to polarized layer dispersion.

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26

Schopf, Roland, Florian Schmidt, Johanna Linner e Ulrich Kulozik. "Comparative Assessment of Tubular Ceramic, Spiral Wound, and Hollow Fiber Membrane Microfiltration Module Systems for Milk Protein Fractionation". Foods 10, n. 4 (24 marzo 2021): 692. http://dx.doi.org/10.3390/foods10040692.

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Abstract (sommario):

The fractionation efficiency of hollow fiber membranes (HFM) for milk protein fractionation was compared to ceramic tubular membranes (CTM) and spiral wound membranes (SWM). HFM combine the features of high membrane packing density of SWM and the more defined flow conditions and better control of membrane fouling in the open flow channel cross-sections of CTM. The aim was to comparatively analyze the effect of variations in local pressure and flow conditions while using single industrially sized standard modules with similar dimensions and module footprints (module diameter and length). The comparative assessment with varied transmembrane pressure was first applied for a constant feed volume flow rate of 20 m3 h−1 and, secondly, with the same axial pressure drop along the modules of 1.3 bar m−1, similar to commonly applied crossflow velocity and wall shear stress conditions at the industrial level. Flux, transmission factor of proteins (whey proteins and serum caseins), and specific protein mass flow per area membrane and per volume of module installed were determined as the evaluation criteria. The casein-to-whey protein ratios were calculated as a measure for protein fractionation effect. Results obtained show that HFM, which so far are under-represented as standard module types in industrial dairy applications, appear to be a competitive alternative to SWM and CTM for milk protein fractionation.

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27

Razi, Fachrul, Sri Mulyati e Nasrul Arahman. "The performance of bovine serum albumin filtration by using polyethersulfone-Tetronic 304 blend Ultrafiltration Membrane". F1000Research 8 (7 novembre 2019): 953. http://dx.doi.org/10.12688/f1000research.18740.2.

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Abstract (sommario):

Background: Membrane technology has been widely applied for protein purification. In applications for protein separation, a membrane with stable filtration performance is necessary. In this work, two types of hollow fiber membranes with different characteristic were used to study the filtration profile of bovine serum albumin. Methods: A single piece of hollow fiber module was used for ultrafiltration testing using UF0 and UFT304 membranes. Flux and rejection of BSA solution were collected based on a pressure-driven inside filtration model. Results: Ultrafiltration experiments showed that the flux of UFT304 membrane was higher than that of UF0 membrane in all applied pressure condition. Solute rejection reaches 90 and 88% for ultrafiltration of BSA solution on the operating pressure of 0.5 atm using UF0 and UFT304 membranes, respectively. Conclusion: In general, UFT304 membranes has better ultrafiltration performance for BSA separation than UF0 membranes. The UFT304 membrane has a more stable flux for up to two hours of filtration.

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28

Kim, Do Hee, Kyoung Woong Kim e Jaeweon Cho. "Removal and transport mechanisms of arsenics in UF and NF membrane processes". Journal of Water and Health 4, n. 2 (1 giugno 2006): 215–23. http://dx.doi.org/10.2166/wh.2006.0018.

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Abstract (sommario):

In this study, the removal and transport mechanisms of ionized and non-ionized arsenics through NF and UF membranes were systemically investigated. The charge repulsion between the membrane surface and arsenic ions was an important mechanism for the rejection of ions by a charged membrane. In addition, the effect of J0/k ratio was dependent on the membrane and ion charge, but the cross-flow velocity was not significantly affected. Both diffusion and convection are proved to affect the transport of arsenic ions. The reflection coefficients (σ) of both UF and NF membranes increased with increasing pH; the reflection coefficients of arsenate were higher than those of arsenite under the same operating conditions. The spiral-wound module exhibited slightly higher arsenate removal than the flat-sheet module under the same operating conditions.

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29

Bopape, Mokgadi F., Tim Van Geel, Abhishek Dutta, Bart Van der Bruggen e Maurice Stephen Onyango. "Numerical Modelling Assisted Design of a Compact Ultrafiltration (UF) Flat Sheet Membrane Module". Membranes 11, n. 1 (14 gennaio 2021): 54. http://dx.doi.org/10.3390/membranes11010054.

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Abstract (sommario):

The increasing adoption of ultra-low pressure (ULP) membrane systems for drinking water treatment in small rural communities is currently hindered by a limited number of studies on module design. Detailed knowledge on both intrinsic membrane transport properties and fluid hydrodynamics within the module is essential in understanding ULP performance prediction, mass transfer analysis for scaling-up between lab-scale and industrial scale research. In comparison to hollow fiber membranes, flat sheet membranes present certain advantages such as simple manufacture, sheet replacement for cleaning, moderate packing density and low to moderate energy usage. In the present case study, a numerical model using computational fluid dynamics (CFD) of a novel custom flat sheet membrane module has been designed in 3D to predict fluid flow conditions. The permeate flux through the membrane decreased with an increase in spacer curviness from 2.81 L/m2h for no (0%) curviness to 2.73 L/m2h for full (100%) curviness. A parametric analysis on configuration variables was carried out to determine the optimum design variables and no significant influence of spacer inflow or outflow thickness on the fluid flow were observed. The numerical model provides the necessary information on the role of geometrical and operating parameters for fabricating a module prototype where access to technical expertise is limited.

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30

Zhou, Yukang, Long Chen, Mengtao Huang, Weilian Hu, Guicai Chen e Binxin Wu. "Experimental Investigation of the Desalination Process for Direct Contact Membrane Distillation Using Plate and Frame Membrane Module". Applied Sciences 13, n. 16 (21 agosto 2023): 9439. http://dx.doi.org/10.3390/app13169439.

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Abstract (sommario):

Through experiments, the effect of membrane material selection and operating conditions on permeate fluxes in direct contact membrane distillation (DCMD) desalination was investigated. The experiment used a plate and frame membrane module, and with nine different hydrophobic porous membranes, a comparative analysis of the desalination performance of 3 wt% NaCl solution was performed. The results of this experiment were compared to find out the effect of different materials, pore sizes and membrane thicknesses on the permeate flux under same operating conditions. Further, a three-factor, three-level orthogonal experiment was designed. The effects of hot-side temperature, hot-side inlet flow and cold-side inlet flow on the permeate flux of PTFE membranes with a pore size of 0.22 μm were investigated when the temperature on the cold side was set at 20 °C. The results showed that in the DCMD experiments, both PTFE and PVDF membranes performed well, and that hot-side inlet temperatures and cold-side inlet flow rates had significant effects on the permeate flux.

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31

Razi, Fachrul, Sri Mulyati e Nasrul Arahman. "The performance of bovine serum albumin filtration by using polyethersulfone-Tetronic 304 blend Ultrafiltration Membrane". F1000Research 8 (24 giugno 2019): 953. http://dx.doi.org/10.12688/f1000research.18740.1.

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Abstract (sommario):

Background: Membrane technology has been widely applied for protein purification. In applications for protein separation, a membrane with stable filtration performance is necessary. In this work, two types of hollow fiber membranes with different characteristic were used to study the filtration profile of bovine serum albumin. Methods: A single piece of hollow fiber module was used for ultrafiltration testing using UF0 and UFT304 membranes. Flux and rejection of BSA solution were collected based on a pressure-driven inside filtration model. Results: Ultrafiltration experiments showed that the flux of UFT304 membrane was higher than that of UF0 membrane in all applied pressure condition. Solute rejection was achieved up to 90% for ultrafiltration of BSA solution by using UF0 membrane obtained on the operating pressure of 0.5 atm. Conclusion: In general, UFT304 membranes has better ultrafiltration performance for BSA separation than UF0 membranes. The UFT304 membrane has a more stable flux for up to two hours of filtration.

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32

Henmi, Masahiro, e Tadahiro Uemura. "PVDF Membrane Module For Membrane Bioreactor". MEMBRANE 30, n. 5 (2005): 282–85. http://dx.doi.org/10.5360/membrane.30.282.

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33

Fedotov, Yu A., A. V. Tarasov, Yu A. Rakhmanin, A. E. Nedachin, S. A. Lepeshin, A. I. Fedotova e Yu T. Panov. "Possibility of Using Modified Polyamide Membranes for Virus Concentration for the Purposes of Sanitary-Virological Analysis of Water". Eurasian Chemico-Technological Journal 14, n. 3 (23 maggio 2012): 233. http://dx.doi.org/10.18321/ectj119.

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Abstract (sommario):

The results of investigations of modified polyamide microfiltration membranes application in the concentration of viruses and bacteriophages during sanitary virological monitoring of water bodies are presented in this paper. The analysis of developments in the control of viral contamination of different origins water bodies is given. Viruses presented in the water in small amounts can cause disease. It is shown that an important step is viral concentration from large amounts of water for its identification. The possibility of positively charged microfiltration membranes application in the concentration of viruses is established. A method of polyamide microfiltration membranes modification for increasing the positive charge on their surface is developed. To estimate the retention capacity of membranes the methods of measuring the sorption properties of the membranes using the model dye bromophenyl blue is developed. A membrane filter module with tangentially-radial mode of fluid movement was used. Studies carried out in specialized organizations revealed that the efficiency of bacteriophage MS-2 sorption on the modified polyamide membrane at different loads was 100%. It was found that the use of membrane filtration module not only improves the detention of microorganisms, but also allows improving the elution stage. The laboratory results were confirmed by tests using natural waters.

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34

Pervov, Alexey G., e Dmitriy V. Spitsov. "Reducing operating costs through modernization of reverse osmosis facilities used to produce drinking water". Vestnik MGSU, n. 5 (maggio 2022): 628–45. http://dx.doi.org/10.22227/1997-0935.2022.5.628-645.

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Abstract (sommario):

Introduction. The authors address problems of operation of reverse osmosis facilities, used to treat ground water and produce drinking water; they also focus on operating cost reduction strategies. Nanofiltration membranes may reduce operating costs, concentrate consumption, and sedimentation. A smaller antiscalant dosage can also reduce the cost of chemicals. The purpose of this research is to evaluate the ecological and economic efficiency of the new technique. Materials and methods. The authors conducted groundwater treatment experiments to reduce groundwater hardness and ammonia content. Scaling rates and the composition of water, produced by each membrane module, were determined in each membrane module depending on coefficient K values. Results. The relationships, identified in the course of experiments, enabled the authors to calculate the number of membranes required to reach the designed efficiency value. The design of a membrane facility, tailored to a certain groundwater composition, is presented; membrane models and treatment efficiency values are identified. The use of nanofiltration membranes reduces the operating costs by 40 percent due to the lower consumption of antiscalants, power, and concentrate. Conclusions. The research has proven that the replacement of reverse osmosis membranes by nanofiltration membranes at the water treatment facilities in operation ensures a 40–50 percent increase in their production capacity. The water quality remains the same and meets the WHO standards. Also, the concentrate consumption rate goes down 10–20-fold. The authors have also found out that the use of nanofiltration membranes reduces the water hardness and ammonia content at lower pressure values and scaling rates, although the safe operation and higher efficiency are in place. The proposed modernization strategy reduces operating costs by 40–50 percent through membrane replacement without any changes in the membrane design.

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35

Albu, Paul Constantin, Szidonia-Katalin Tanczos, Andreea Ferencz (Dinu), Andreia Pîrțac, Alexandra Raluca Grosu, Dumitru Pașcu, Vlad-Alexandru Grosu, Constantin Bungău e Aurelia Cristina Nechifor. "pH and Design on n–Alkyl Alcohol Bulk Liquid Membranes for Improving Phenol Derivative Transport and Separation". Membranes 12, n. 4 (26 marzo 2022): 365. http://dx.doi.org/10.3390/membranes12040365.

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Abstract (sommario):

Regardless of the type of liquid membrane (LM) (Bulk Liquid Membranes (BLM), Supported Liquid Membranes (SLM) or Emulsion Liquid Membranes (ELM)), transport and separation of chemical species are conditioned by the operational (OP) and constructive design parameters (DP) of the permeation module. In the present study, the pH of the aqueous source phase (SP) and receiving phase (RP) of the proposed membrane system were selected as operational parameters. The mode of contacting the phases was chosen as the convective transport generator. The experiments used BLM-type membranes with spheres in free rotation as film contact elements of the aqueous phases with the membrane. The target chemical species were selected in the range of phenol derivatives (PD), 4–nitrophenol (NP), 2,4–dichlorophenol (DCP) and 2,4–dinitrophenol (DNP), all being substances of technical-economic and environmental interest. Due to their acid character, they allow the evaluation of the influence of pH as a determining operational parameter of transport and separation through a membrane consisting of n–octanol or n–decanol (n–AlcM). The comparative study performed for the transport of 4–nitrophenol (NP) showed that the module based on spheres (Ms) was more performant than the one with phase dispersion under the form of droplets (Md). The sphere material influenced the transport of 4–nitrophenol (NP). The transport module with glass spheres (Gl) was superior to the one using copper spheres (Cu), but especially with the one with steel spheres (St). In all the studied cases, the sphere-based module (Ms) had superior transport results compared to the module with droplets (Md). The extraction efficiency (EE) and the transport of 2,4–dichlorophenol (DCP) and 2,4–dinitrophenol (DNP), studied in the module with glass spheres, showed that the two phenolic derivatives could be separated by adjusting the pH of the source phase. At the acidic pH of the source phase (pH = 2), the two derivatives were extracted with good results (EE > 90%), while for pH values ranging from 4 to 6, they could be separated, with DCP having doubled separation efficiency compared to DNP. At a pH of 8 in the source phase, the extraction efficiency halved for both phenolic compounds.

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Fane, A. G., P. Beatson e H. Li. "Membrane fouling and its control in environmental applications". Water Science and Technology 41, n. 10-11 (1 maggio 2000): 303–8. http://dx.doi.org/10.2166/wst.2000.0667.

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Abstract (sommario):

Fouling is an issue in the application of membranes to environmental management. This paper describes recent developments in fouling analysis and membrane autopsy. Methods of fouling control are described with examples of feed pretreatment, membrane selection, module design and selection and mode of operation.

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37

Subramaniam, M. N., e Z. Wu. "Grand Challenges in Fabrication of Nanocomposite Hollow Fiber Membranes". Journal of Applied Membrane Science & Technology 26, n. 3 (20 novembre 2022): 37–43. http://dx.doi.org/10.11113/amst.v26n3.251.

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Abstract (sommario):

Membrane processes allow scalable and energy-efficient separation of gas and liquid, advance low-carbon purifications in various industrial and environmental applications and enable more resilient economy and society. In pursuit of developing more advanced membranes with continuously improved separating performances, nanofillers have been commonly incorporated into membranes to upgrade membrane properties such as mechanical robustness, antifouling ability, and permeability etc., across all types of popular membrane geometries from flat sheet and spiral wound to hollow fiber. Nanofillers inside hollow fibre membranes have received more attentions due to the unique structural advantages such as a large surface area/volume ratio and compact module designs. The resultant nanocomposite hollow fiber membranes thus combine the structural superiority with specific functions of nanomaterials such as superhydrophilicity or catalytic activity, whereas the development of dual layer hollow fiber membrane allowed further design of both the inner and outer membrane layers with innovative functions. On the other hand, greener and more environmentally friendly membranes fabrication are increasingly important to sustainable membrane technology, for example topics of using natural polymers, solvent free membrane fabrication and nano-pollutions are fervently investigated.

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38

Yao, Ying, Wei Liu, Hui Feng Zhang, Rong Hua Cai, Ying Wang, Shu Bao Gao, Dan Wu e Yu Shan Zhang. "Research on the PVDF Hollow Fiber Gas Membrane Used for Bromine Extraction". Advanced Materials Research 217-218 (marzo 2011): 802–7. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.802.

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Abstract (sommario):

In this paper, several types of PVDF hollow fiber membranes used in the gas membrane separation process for extracting bromine from simulated seawater or concentrated seawater were studied. The micropore, hydrophobic property, mechanical strength and material chemistry of the PVDF membranes soaked in seawater or concentrated seawater were characterized by SEM-EDX, IR, contact angle testing instrument and electronic fabric strength tester, which were compared with those of origin membranes. At last, the mass transfer coefficient and flux during a long time were gained by operating a permeation experiment with a chosen type of PVDF membrane module.

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39

Drago, Francesca, Paolo Fedeli, Angelo Cavaliere, Andrea Cammi, Stefano Passoni, Riccardo Mereu, Stefano De La Pierre, Federico Smeacetto e Monica Ferraris. "Development of a Membrane Module Prototype for Oxygen Separation in Industrial Applications". Membranes 12, n. 2 (30 gennaio 2022): 167. http://dx.doi.org/10.3390/membranes12020167.

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Abstract (sommario):

The integration of oxygen transport membranes in industrial processes can lead to energy and economic advantages, but proof of concept membrane modules are highly necessary to demonstrate the feasibility of this technology. In this work, we describe the development of a lab-scale module through a comprehensive study that takes into consideration all the relevant technological aspects to achieve a prototype ready to be operated in industrial environment. We employed scalable techniques to manufacture planar La0.6Sr0.4Co0.2Fe0.8O3-δ membrane components suitable for the application in both 3- and 4-end mode, designed with a geometry that guarantees a failure probability under real operating conditions as low as 2.2 × 10−6. The asymmetric membranes that act as separation layers showed a permeation of approx. 3 NmL/min/cm2 at 900 °C in air/He gradient, with a remarkable stability up to 720 h, and we used permeation results to develop a CFD model that describes the influence of the working conditions on the module performance. The housing of the membrane component is an Inconel 625 case joined to the membrane component by means of a custom-developed glass–ceramic sealant that exhibited a remarkable thermo-chemical compatibility both with metal and ceramic, despite the appearance of chemical strain in LSCF at high temperature. The multi-disciplinary approach followed in this work is suitable to be adapted to other module concepts based on membrane components with different dimensions, layouts or materials.

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40

Kondo, Masakazu, Yasuo Matuo, Yosio Morigami e Jun Abe. "Tubular-type pervaporation module with NaA membrane." membrane 23, n. 2 (1998): 95–99. http://dx.doi.org/10.5360/membrane.23.95.

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41

Ogawa, Takashi. "PVDF Submerged Type Membrane Module and Application". MEMBRANE 36, n. 1 (2011): 44–47. http://dx.doi.org/10.5360/membrane.36.44.

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42

Okoro, Emmanuel E., Rachael Josephs, Samuel E. Sanni e Yuven Nchila. "Advances in the Use of Nanocomposite Membranes for Carbon Capture Operations". International Journal of Chemical Engineering 2021 (18 giugno 2021): 1–22. http://dx.doi.org/10.1155/2021/6666242.

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Abstract (sommario):

The adoption of nanodoped membranes in the areas of gas stream separation, water, and wastewater treatments due to the physical and operational advantages of such membranes has significantly increased. The literature has shown that the surface structure and physicochemical properties of nanodoped membranes contribute significantly to the interaction and rejection characteristics when compared to bare membranes. This study reviews the recent developments on nanodoped membranes, and their hybrids for carbon capture and gas separation operations. Features such as the nanoparticles/materials and hybrids used for membrane doping and the effect of physicochemical properties and water vapour in nanodoped membrane performance for carbon capture are discussed. The highlights of this review show that nanodoped membrane is a facile modification technique which improves the membrane performance in most cases and holds a great potential for carbon capture. Membrane module design and material, thickness, structure, and configuration were identified as key factors that contribute directly, to nanodoped membrane performance. This study also affirms that the three core parameters satisfied before turning a microporous material into a membrane are as follows: high permeability and selectivity, ease of fabrication, and robust structure. From the findings, it is also observed that the application of smart models and knowledge-based systems have not been extensively studied in nanoparticle-/material-doped membranes. More studies are encouraged because technical improvements are needed in order to achieve high performance of carbon capture using nanodoped membranes, as well as improving their durability, permeability, and selectivity of the membrane.

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43

Pientka, Zbyněk, Jakub Peter e Robert Válek. "Membrane Unit for Integrated Gas Separation – Membrane Bioreactor (GS-MBR) System". Hungarian Journal of Industry and Chemistry 50, n. 1 (27 settembre 2022): 15–22. http://dx.doi.org/10.33927/hjic-2022-04.

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One of the research directions of renewable energy sources is the production of biohydrogen from the dark fermentation of organic matter. During this fermentation process, since hydrogen is produced along with a complex mixture of other gases and vapors, hydrogen gas requires further purification. One relatively easy solution to this problem might be the utilization of gas separation membrane modules given their low energy consumption, simple operation and ease of upscaling. In this work, hollow fiber (HF) membranes based on polyetherimide (PEI) were developed and tested. HF membranes were spun from a polymer solution of PEI using the wet phase inversion process into a water bath using a pilot-scale spinning device. Gas transport measurements showed that membranes exhibited permeances of between 9.3 and 19.2 GPU with CO2/H2 selectivities within the range of 3.3 - 5.6. Morphology studies showed regular shapes resembling hollow fibers with outer diameters within the range of 250-320 microns, depending on various parameters of the spinning process. The best performing membranes were selected and a morphological analysis carried out. Selected fibers were incorporated into two types of membrane modules. One type was a laboratory-scale membrane mini-module used for preliminary tests, while the other membrane module was designed for the treatment of larger amounts of biohydrogen. Two types of laboratory-scale membrane separation units were constructed. For laboratory use, the low-pressure unit proved more accurate regulation to match the fermenters performance with the separation unit in comparison with the high-pressure one.

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Brown, Andrew J., Nicholas A. Brunelli, Kiwon Eum, Fereshteh Rashidi, J. R. Johnson, William J. Koros, Christopher W. Jones e Sankar Nair. "Interfacial microfluidic processing of metal-organic framework hollow fiber membranes". Science 345, n. 6192 (3 luglio 2014): 72–75. http://dx.doi.org/10.1126/science.1251181.

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Molecular sieving metal-organic framework (MOF) membranes have great potential for energy-efficient chemical separations, but a major hurdle is the lack of a scalable and inexpensive membrane fabrication mechanism. We describe a route for processing MOF membranes in polymeric hollow fibers, combining a two-solvent interfacial approach for positional control over membrane formation (at inner and outer surfaces, or in the bulk, of the fibers), a microfluidic approach to replenishment or recycling of reactants, and an in situ module for membrane fabrication and permeation. We fabricated continuous molecular sieving ZIF-8 membranes in single and multiple poly(amide-imide) hollow fibers, with H2/C3H8 and C3H6/C3H8 separation factors as high as 370 and 12, respectively. We also demonstrate positional control of the ZIF-8 films and characterize the contributions of membrane defects and lumen bypass.

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Vanhaecke, T., P. A. Grohard, P. Aubert, J. Jaulin, J. Chevalier, T. Durand, H. Boudin et al. "Effet protecteur de l’administration de membranes du globule gras du lait et L. fermentum CECT 5716 sur les fonctions digestives et sur la réponse inflammatoire dans un modèle de rat nouveau-né". Nutrition Clinique et Métabolisme 31, n. 3 (settembre 2017): 221–22. http://dx.doi.org/10.1016/j.nupar.2017.06.015.

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46

Zhao, Zhi Peng, Yue Feng Su, Mi Yi Li e Wen Sheng Deng. "The Molecular Simulation Study of Optimum Blending Ratio for PVDF/PVC Membrane". Advanced Materials Research 968 (giugno 2014): 25–30. http://dx.doi.org/10.4028/www.scientific.net/amr.968.25.

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The PVDF/PVC blending membrane has a certain application in the field of sewage treatment. In this paper, the simulation study for the blending ratio of the PVDF/PVC membrane has been carried on, which has an influence on the membrane’s ability of sewage treatment. Firstly, the membrane models were constructed via Amorphous Cell module of MS (material studios) 6.0. Secondly, the optimization processes were achieved via Minimizer and MD (Molecular Dynamics) method of the Discover module. Lastly, the diffusion coefficients D was calculated indirectly through the Mean square displacement (MSD) getting from Forcite module and the solubility coefficients S was calculated indirectly through the adsorption isotherm getting from Sorption module. It was found that the membrane had a best ability of sewage treatment when the content of PVC was 5% (mass fraction). And the calculated result was well consistent with experiment result.

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Hosseini, Seyed Saeid, Sara Najari, Prodip K. Kundu, Nicolas R. Tan e Seyed Mehrdad Roodashti. "Simulation and sensitivity analysis of transport in asymmetric hollow fiber membrane permeators for air separation". RSC Advances 5, n. 105 (2015): 86359–70. http://dx.doi.org/10.1039/c5ra13943k.

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Development of advanced membranes requires deep insights about the process. Sensitivity analysis is performed to analyze the effects of module properties and process operational conditions on the performance of air separation membrane permeators.

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Yoon, Sukmin, Young-Joo Lee, Seong-Su Kim, Han-Bong Choi e No-Suk Park. "Research on Autopsy Results of over 10 Year Old Low Pressure Hollow Fiber Membrane from Domestic Water Treatment Plant". Journal of Korean Society of Environmental Engineers 44, n. 9 (30 settembre 2022): 287–97. http://dx.doi.org/10.4491/ksee.2022.44.9.287.

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Objectives : In this study, membrane autopsy was performed for a parallel arrayed low-pressure membrane (microfiltration) filtration process that is actually applied to water treatment, to check out whether there are differences in the degree of membrane fouling due to the uneven flow rate into each module. Also, membrane foulants were evaluated quantitatively.Methods : In this study, autopsy was performed for over 10 year old membranes used for drinking water purification. In this way, the outer casings of membrane modules at different positions were disassembled and visually observed. In addition, In addition, the size of the pores and the porosity were investigated by taking a SEM (Scanning Electron Microscope) photograph for the new and the used membrane module fiber samples in different positions from the header pipe. The used membrane foulants were classified into organic and inorganic matters and quantitatively analyzed.Results and Discussion : As a result of visually observing inside the membrane module that has produced drinking water for over 10 years, the inside of the No. 1 membrane module close to the inlet was contaminated with black foulants. On the other hand, in the case of No. 10 membrane module located farthest from the header pipe inlet, no foulants were observed with the naked eye. Also, it was observed from SEM photograph results that there were large differences in the surfaces among No. 1, 4, 6, 8 and 10 MF module fibers.Conclusion : Even after periodic physical and chemical cleaning, it was concluded that the fouling levels were different each other in the parallel arrayed low-pressure membrane modules. In addition, the pore size distribution and porosities of the membrane modules may vary depending on the position.

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Henmi, Masahiro, Atsuo Kumano, Shuji Nakatsuka e Hideto Matsuyama. "High Efficient Membrane, Large Size Element and Module". membrane 40, n. 2 (2015): 60–66. http://dx.doi.org/10.5360/membrane.40.60.

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50

Yabuno, Youhei. "High Flux Type Hollow Fiber Membrane Module “GL”". MEMBRANE 41, n. 6 (2016): 311–14. http://dx.doi.org/10.5360/membrane.41.311.

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