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New Phenomenological Findings in Nanofiltration

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A special issue of Membranes (ISSN 2077-0375). This special issue belongs to the section "Membrane Processing and Engineering".

Deadline for manuscript submissions: closed (31 October 2021) | Viewed by 37161

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Special Issue Editors

Prof. Dr. Wolfgang Samhaber

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Institute of Process Engineering (IVT), Johannes Kepler University Linz, Altenberger Str. 69, A-4040 Linz, Austria
Interests: characterization and modification of polymer membranes; synthesis and characterization of emulsion polymerization; isolation and cleaning of aromatic and natural products and active components; down-stream processing of natural and synthesised products
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Dr. Mohammad Rezaei

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Institute of Process Engineering (IVT), Johannes Kepler University Linz, Altenberger Str. 69, A-4040 Linz, Austria
Interests: membrane distillation
Special Issues, Collections and Topics in MDPI journals

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Dear Colleagues,

The characterization of nanofiltration membranes is not as simple as that of RO membranes, which by definition only let water through. NF membranes, on the other hand, which are less dense than RO membranes, are called both porous and non-porous membranes.

NF membranes with narrower pores are described with a noticeable steric hindrance even of small inorganic ions. Retention by a sieving mechanism seems to be feasible with these membranes. In the case of membrane retention, which on the other hand is not attributed to a sieve effect, the exclusion of Donnan, a dielectric exclusion mechanism, charge effects near the membrane surface or an exclusion effect due to a hydration mechanism, which is also associated with solution effects in the membrane, are described.

Different mechanisms describe the selectivity of NF membranes for various complex separation tasks. The further development of predictive concepts is the focus of this Special Issue, which is intended to deepen the basic understanding of the predominant phenomena of NF processes.

Prof. Dr. Wolfgang Samhaber
Prof. Dr. Mohammad Rezaei
Guest Editors

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Keywords

Nanofiltration
Membranes
Separation Phenomena
Selective Transport

Published Papers (13 papers)

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Research

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23 pages, 4427 KiB

Open AccessArticle

Impact of Polymer Membrane Properties on the Removal of Pharmaceuticals

by Renata Żyłła, Magdalena Foszpańczyk, Irena Kamińska, Marcin Kudzin, Jacek Balcerzak and Stanisław Ledakowicz

Membranes 2022, 12(2), 150; https://doi.org/10.3390/membranes12020150 - 26 Jan 2022

Cited by 12 | Viewed by 2749

Abstract

The influence of various factors on the removal efficiency of selected pharmaceuticals by membrane filtration was investigated. Several commercial polymer membranes were used for nanofiltration (NF) from various manufacturers. The studies were conducted for ibuprofen (IBF), amoxicillin (AMX), diclofenac (DCF), tetracycline (TRC), salicylic acid (SA) and acetylsalicylic acid (ASA). The influence of the structure and properties of the tested compounds on the retention coefficient and filtration rate was investigated. The influence of pH on the filtration parameters was also checked. The properties of selected membranes influencing the retention of pharmaceuticals and filtrate flux were analysed. An extensive analysis of the retention coefficients dependence on the contact angle and surface free energy was performed. It was found that there is a correlation between the hydrophilicity of the membrane and the effectiveness and efficiency of the membrane. As the contact angle of membrane increased, the flow rate of the filtrate stream increased, while the retention coefficient decreased. The studies showed that the best separation efficiency was achieved for compounds with a molecular weight (MW) greater than 300 g/mol. During the filtration of pharmaceuticals with MW ranging from 300 to 450 g/mol, the type of membrane used practically did not affect the filtration efficiency and a high degree of retention was achieved. In the case of low MW molecules (SA and ASA), a significant decrease in the separation efficiency during the process was noted. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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14 pages, 5692 KiB

Open AccessArticle

Removal of Organic Compounds with an Amino Group during the Nanofiltration Process

by Renata Żyłła, Magdalena Foszpańczyk, Magdalena Olak-Kucharczyk, Joanna Marszałek and Stanisław Ledakowicz

Membranes 2022, 12(1), 58; https://doi.org/10.3390/membranes12010058 - 31 Dec 2021

Cited by 4 | Viewed by 1726

Abstract

The research covered the process of nanofiltration of low molecular weight organic compounds in aqueous solution. The article presents the results of experiments on membrane filtration of compounds containing amino groups in the aromatic ring and comparing them with the results for compounds without amino groups. The research was carried out for several commercial polymer membranes: HL, TS40, TS80, DL from various manufacturers. It has been shown that the presence of the amino group and its position in relation to the carboxyl group in the molecule affects the retention in the nanofiltration process. The research also included the oxidation products of selected pharmaceuticals. It has been shown that 4-Amino-3,5-dichlorophenol—a oxidation product of diclofenac and 4-ethylbenzaldehyde—a oxidation product of IBU, show poor separation efficiency on the selected commercial membranes, regardless of the pH value and the presence of natural organic matter (NOM). It has been shown that pre-ozonation of natural river water can improve the retention of pollutants removed. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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16 pages, 2557 KiB

Open AccessArticle

Organic Solvent Nanofiltration of Water-in-Oil Pickering Emulsions—What Influences Permeability?

by Maresa Vivien Kempin and Anja Drews

Membranes 2021, 11(11), 864; https://doi.org/10.3390/membranes11110864 - 10 Nov 2021

Cited by 2 | Viewed by 1760

Abstract

Pickering emulsions (PEs) have received increasing interest for their application in catalytic multiphase reactions. Organic solvent nanofiltration of PEs was shown to be a promising procedure for efficient and effective catalyst recycling. In this work, a systematic parameter study to identify the main influencing parameters on PE filtration was conducted for a large variety of PE compositions for the first time. In addition to temperature, only the type of organic solvent significantly influenced the filtration performance, which could be mathematically modeled via a combination of the solution–diffusion and the resistance in the series model. Particle type and concentration, dispersed phase fraction and the presence of reaction (by-)products did not show any significant impact on the permeability. The stirrer speed only became important when emulsions stabilized by particles without the tendency to form 3D network structures were filtered in long-term filtration experiments. These results pave the way towards the application of PE membrane filtration for catalyst recovery in continuous liquid/liquid multiphase reactions and enable broad operation windows. As the mechanical separation of PEs was shown to be a very robust process, the emulsion composition can now be tuned to meet the needs of the reaction without any (significant) loss in filtration performance. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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9 pages, 1902 KiB

Open AccessArticle

Recycling and Separation of Homogeneous Catalyst from Aqueous Multicomponent Mixture by Organic Solvent Nanofiltration

by J.-Kilian Schnoor, Jens Bettmer, Johannes Kamp, Matthias Wessling and Marcel A. Liauw

Membranes 2021, 11(6), 423; https://doi.org/10.3390/membranes11060423 - 31 May 2021

Cited by 5 | Viewed by 2397

Abstract

Organic solvent nanofiltration (OSN) has evolved to an established recycling method for homogeneous catalysts. However, commercial availability has not circumvented the need for classification and the scoping of possible applications for specific solvent mixtures. Therefore, Evonik’s DuraMem^® 300 was assessed for the recycling of magnesium triflate at two transmembrane pressures from a mixture of ethanol, ethyl acetate and water. Catalyst retention up to 98% and permeability of up to 4.44·10⁻¹∙L∙bar⁻¹∙m⁻²∙h⁻¹ were possible when less than 25% ethyl acetate was in the mixture. The retention of some of the components in the ternary mixture was observed while others were enriched, making the membrane also suitable for fractioning thereof. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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16 pages, 2707 KiB

Open AccessArticle

Advances in the Understanding of the Transfer of Saccharides through NF Membranes in the Presence of Electrolytes by Coupling Quantum Mechanics and Thermodynamic Methods

by Johanne Teychené, Hélène Roux-de Balmann and Sylvain Galier

Membranes 2021, 11(5), 341; https://doi.org/10.3390/membranes11050341 - 5 May 2021

Cited by 1 | Viewed by 1931

Abstract

Different studies have shown that the presence of electrolytes modifies the nanofiltration performances and that the variation of the neutral solute transfer is mainly governed by the modification of the solute properties. The objective of this work is to strengthen the understanding of the impact of the ion composition and to progress in the long-term objective for the prediction of the nanofiltration performances. The methodology is based on the comparison of the hydration properties obtained by experimental and theoretical approaches with the mass transfer of saccharides. The key role of the saccharide hydration number to understand the impact of the ionic composition on the saccharide transfer is clearly demonstrated. Moreover, it is established that the number of saccharide/cation interactions, which increases with the cation coordination number, is a key parameter to understand the mechanisms governing the impact of the nature of the cation on the saccharide mass transfer modification. Finally, correlations are obtained between the saccharide hydration number decrease and the variation of the saccharide radius calculated using a hydrodynamic model for different ionic compositions and operating modes (diffusion and filtration). From these results, it could be possible to evaluate the saccharide transfer for a given saccharide/electrolyte system transfer. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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12 pages, 6275 KiB

Open AccessArticle

Influences of Technological Parameters on Cross-Flow Nanofiltration of Cranberry Juice

by Dat Quoc Lai, Nobuhiro Tagashira, Shoji Hagiwara, Mitsutoshi Nakajima, Toshinori Kimura and Hiroshi Nabetani

Membranes 2021, 11(5), 329; https://doi.org/10.3390/membranes11050329 - 29 Apr 2021

Cited by 3 | Viewed by 2067

Abstract

The paper focused on the influence of operative conditions on the separation of benzoic acid from 10 °Brix cranberry juice by cross-flow nanofiltration with a plate and frame pilot scale (DDS Lab Module Type 20 system). Six kinds of commercial nanofiltration membrane were investigated. The results showed that the rejection of benzoic acid was significantly lower than that of other components in cranberry juice, including sugars and other organic acids. In a range of 2–7.5 L/min, feed flow rate slightly affected the performance of nanofiltration. Higher temperatures resulted in higher permeate flux and lower rejection of benzoic acid, whereas rejection of sugar and organic acid was stable at a high value. In a range of 2.5–5.5, pH also significantly affected the separation of benzoic acid and negative rejection against benzoic acid was observed at pH 4.5 with some of the membranes. This implies that pH 4.5 is considered as an optimum pH for benzoic acid separation from cranberry juice. The lower permeate flux caused a lower rejection of benzoic acid and negative rejection of benzoic acid was observed at the low permeate flux. Pretreatment by ultrafiltration with CR61PP membranes could improve the permeate flux but insignificantly influenced the efficiency of separation. The results also indicated that NF99 and DK membranes can be effectively used to separate benzoic acid from cranberry juice. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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18 pages, 1387 KiB

Open AccessArticle

Concentration with Nanofiltration of Red Wine Cabernet Sauvignon Produced from Conventionally and Ecologically Grown Grapes: Effect on Phenolic Compounds and Antioxidant Activity

by Ivana Ivić, Mirela Kopjar, Dubravko Pichler, Ivana Buljeta and Anita Pichler

Membranes 2021, 11(5), 322; https://doi.org/10.3390/membranes11050322 - 28 Apr 2021

Cited by 3 | Viewed by 2361

Abstract

The aim of this study was to investigate the influence of different operating conditions (four pressures: 2.5, 3.5, 4.5 and 5.5 MPa; two temperature regimes: with and without cooling) and wine type on phenolic compounds retention during the nanofiltration process of two Cabernet Sauvignon red wines (conventionally and ecologically produced). The nanofiltration process was conducted on Alfa Laval LabUnit M20 with plate module and six NF M20 membranes. In initial wines and obtained retentates, total polyphenol and flavonoid contents, monomeric anthocyanins content, antioxidant activity, individual phenolic compounds and CIELab colour parameters were determined. A loss of total phenolic compounds and decrease in antioxidant activity was observed in all retentates comparing to initial wine. However, retentate cooling and higher pressure increased their retention. Besides processing parameters, individual phenolic compound retention depended on several factors, such as the wine type, chemical properties of compounds and membrane type, and their combinations. Different chemical composition of initial conventional and ecological wine influenced the retention of individual compounds. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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24 pages, 1964 KiB

Open AccessArticle

Concentration with Nanofiltration of Red Wine Cabernet Sauvignon Produced from Conventionally and Ecologically Grown Grapes: Effect on Volatile Compounds and Chemical Composition

by Ivana Ivić, Mirela Kopjar, Jasmina Obhođaš, Andrija Vinković, Dubravko Pichler, Josip Mesić and Anita Pichler

Membranes 2021, 11(5), 320; https://doi.org/10.3390/membranes11050320 - 27 Apr 2021

Cited by 8 | Viewed by 2730

Abstract

Ecological viticulture represent an upward trend in many countries. Unlike conventional viticulture, it avoids the use of chemical fertilizers and other additives, minimizing the impact of chemicals on the environment and human health. The aim of this study was to investigate the influence of nanofiltration (NF) process on volatiles and chemical composition of conventional and ecological Cabernet Sauvignon red wine. The NF process was conducted on laboratory Alfa Laval LabUnit M20 (De Danske Sukkerfabrikker, Nakskov, Denmark) equipped with six NF M20 membranes in a plate module, at two temperature regimes, with and without cooling and four pressures (2.5, 3.5, 4.5 and 5.5 MPa). Different processing parameters significantly influenced the permeate flux which increased when higher pressure was applied. In initial wines and obtained retentates, volatile compounds, chemical composition and elements concentration were determined. The results showed that the higher pressure and retentate cooling was more favourable for total volatiles retention than lower pressure and higher temperature. Individual compound retention depended on its chemical properties, applied processing parameters and wine composition. Nanofiltration process resulted in lower concentrations of ethanol, acetic acid (>50%), 4-ethylphenol and 4-ethylguaiacol (>90%). Different composition of initial feed (conventional and ecological wine) had an important impact on retention of elements. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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13 pages, 13930 KiB

Open AccessArticle

Nanofiltration Composite Membranes Based on KIT-6 and Functionalized KIT-6 Nanoparticles in a Polymeric Matrix with Enhanced Performances

by Gabriela Paun, Viorica Parvulescu, Elena Neagu, Camelia Albu, Larisa Ionita, Monica Elisabeta Maxim, Andrei Munteanu, Madalina Ciobanu and Gabriel Lucian Radu

Membranes 2021, 11(5), 300; https://doi.org/10.3390/membranes11050300 - 21 Apr 2021

Cited by 3 | Viewed by 2554

Abstract

The nanofiltration composite membranes were obtained by incorporation of KIT-6 ordered mesoporous silica, before and after its functionalization with amine groups, into polyphenylene-ether-ether-sulfone (PPEES) matrix. The incorporation of silica nanoparticles into PPEES polymer matrix was evidenced by FTIR and UV–VIS spectroscopy. SEM images of the membranes cross-section and their surface topology, evidenced by AFM, showed a low effect of KIT-6 silica nanoparticles loading and functionalization. The performances of the obtained membranes were appraised in permeation of Chaenomeles japonica fruit extracts and the selective separation of phenolic acids and flavonoids. The obtained results proved that the PPEES with functionalized KIT-6 nanofiltration membrane, we have prepared, is suitable for the polyphenolic compound’s concentration from the natural extracts. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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12 pages, 1816 KiB

Open AccessArticle

Nanofiltration of Multi-Ion Solutions: Quantitative Control of Concentration Polarization and Interpretation by Solution-Diffusion-Electro-Migration Model

by Marc Fernández de Labastida and Andriy Yaroshchuk

Membranes 2021, 11(4), 272; https://doi.org/10.3390/membranes11040272 - 8 Apr 2021

Cited by 8 | Viewed by 2277

Abstract

For effective use of advanced engineering models of nanofiltration quality of experimental input is crucial, especially in electrolyte mixtures where simultaneous rejections of various ions may be very different. In particular, this concerns the quantitative control of concentration polarization (CP). This work used a rotating disklike membrane test cell with equally accessible membrane surface, so the CP extent was the same over the membrane surface. This condition, which is not satisfied in the conventional membrane test cell, made possible correcting for CP easily even in multi-ion systems. Ion rejections were studied experimentally for several dominant salts (NaCl, MgCl₂, Na₂SO₄ and MgSO₄) and trace ions (Na⁺, NH₄⁺, Cl⁻ and NO₃⁻) using NF270 membrane. The solution–diffusion–electro–migration model was used to obtain ion permeances from the experimental measurements. The model could well fit the experimental data except in the case of NH₄⁺. The correlations between the ion permeances and type of dominant salt are discussed in the context of the established mechanisms of NF such as Donnan and dielectric exclusion. The obtained information contributes to the systematic transport characterization of NF membranes and may be ultimately useful for computational fluid dynamics simulations of the performance of the membranes in various applications. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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16 pages, 4563 KiB

Open AccessArticle

Intermolecular Interactions in the Membrane Filtration of Highly Alkaline Steeping Lye

by Klaus Schlackl, Richard Herchl, Lukas Almhofer, Robert H. Bischof, Karin Fackler and Wolfgang Samhaber

Membranes 2021, 11(2), 88; https://doi.org/10.3390/membranes11020088 - 27 Jan 2021

Cited by 5 | Viewed by 1793

Abstract

The reuse of steeping lye is crucial for the sustainable production of viscose fibers. Steeping lye contains hemicellulose and many alkaline degradation products, such as organic acids, so that its purification can be evaluated in terms of total organic carbon removal. When considering purification by membrane filtration, intermolecular interactions between hemicellulose and organic acids can strongly affect their retention efficiency. Herein, we give more insights into the ultrafiltration and nanofiltration of steeping lye and corresponding model solutions. Furthermore, we studied the impact of total organic carbon concentration, hemicellulose concentration and sodium hydroxide concentration on the membrane performance. Hydrogen bonds between hemicellulose and certain types of hydroxy acids increased the retention of the latter. In contrast, charge based repulsion forces led to a decreased retention of a certain type of hydroxy acids. It can be clearly shown that taking intermolecular interactions into account is highly important for the description of complex multicomponent mixtures. In addition, the results can be extended to other, highly alkaline process streams with organic content, such as Kraft pulping liquors. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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14 pages, 3267 KiB

Open AccessArticle

UV-Polymerized Vinylimidazolium Ionic Liquids for Permselective Membranes

by Fridolin O. Sommer, Jana-Sophie Appelt, Ingo Barke, Sylvia Speller and Udo Kragl

Membranes 2020, 10(11), 308; https://doi.org/10.3390/membranes10110308 - 28 Oct 2020

Cited by 2 | Viewed by 2244

Abstract

Ionic liquids are highly charged compounds with increasing applications in material science. A universal approach to synthesize free-standing, vinylalkylimidazolium bromide-containing membranes with an adjustable thickness is presented. By the variation of alkyl side chains, membrane characteristics such as flux and mechanical properties can be adjusted. The simultaneous use of different ionic liquids (ILs) in the synthesis can also improve the membrane properties. In separation application, these charged materials allowed us to retain charged sugars, such as calcium gluconate, by up to 95%, while similar neutral compounds such as glucose passed the membrane. An analysis of the surface conditions using atomic force microscopy (AFM) confirmed the experimental data and explains the decreasing permeance and increased retention of the charged sugars. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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Review

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34 pages, 3444 KiB

Open AccessEditor’s ChoiceReview

Advances and Applications of Hollow Fiber Nanofiltration Membranes: A Review

by Tim Sewerin, Maria G. Elshof, Sonia Matencio, Marcel Boerrigter, Jimmy Yu and Joris de Grooth

Membranes 2021, 11(11), 890; https://doi.org/10.3390/membranes11110890 - 19 Nov 2021

Cited by 27 | Viewed by 8697

Abstract

Hollow fiber nanofiltration (NF) membranes have gained increased attention in recent years, partly driven by the availability of alternatives to polyamide-based dense separation layers. Moreover, the global market for NF has been growing steadily in recent years and is expected to grow even faster. Compared to the traditional spiral-wound configuration, the hollow fiber geometry provides advantages such as low fouling tendencies and effective hydraulic cleaning possibilities. The alternatives to polyamide layers are typically chemically more stable and thus allow operation and cleaning at more extreme conditions. Therefore, these new NF membranes are of interest for use in a variety of applications. In this review, we provide an overview of the applications and emerging opportunities for these membranes. Next to municipal wastewater and drinking water processes, we have put special focus on industrial applications where hollow fiber NF membranes are employed under more strenuous conditions or used to recover specific resources or solutes. Full article

(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)

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