State-of-the-Art Membrane Science and Technology in Germany (2021,2022)

A special issue of Membranes (ISSN 2077-0375).

Deadline for manuscript submissions: closed (20 May 2023) | Viewed by 10396

Special Issue Editors

Institute of Bioprocess Engineering and Pharmaceutical Technology, Mittelhessen University of Applied Sciences, Wiesenstrasse 14, 35390 Giessen, Germany
Interests: bioprocess engineering; bioseparations; membrane processes; membrane reactors; membrane filtration; water treatment; virusfiltration; membrane chromatography
Special Issues, Collections and Topics in MDPI journals
Mechanical Process Engineering and Water Technology, University of Duisburg-Essen, 47057 Duisburg, Germany
Interests: membrane processes; adsorption; drinking water treatment; hybride processes
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Membrane-based separation processes applied to the purification of industrial streams and products and to water and wastewater treatment are also key factors in economic and sustainable development. Membrane processes can replace multiple-step technologies, increasing the efficiency and productivity of separation.

In Germany, membrane processes, e.g., reverse osmosis, nanofiltration, and ultra- and microfiltration, are already applied at an industrial scale for food and bioproduct processing. In addition, membrane processes for water and wastewater treatment (e.g., membrane bioreactors) have been established. Membrane technology is also used in the chemical industry and other industries for the sustainable use of water and other fluids. Academic scientists and industries in Germany have developed new types of membranes and membrane processes and demonstrated their application potential.

In this Special Issue, the current development of membranes and membrane processes for application not only to water treatment but also to various liquid separation, gas separation, energy production, food concentration, and pharmaceutical processes will be collected and shared across the world from Germany through publishing original research papers and review papers. We would like to promote the further development of membrane science and technology and look into the future of membranes and processes.

Contributions for the topics below, related to advances in membrane preparation, characterization, and their application to membrane separation processes in Germany, are welcome, both in the form of experimental and theoretical contributions:

  • Development of new membrane materials and processes;
  • New application area for membrane technology;
  • Methods for mitigation of fouling and scaling;
  • Development of membrane module and membrane installations;
  • Modeling and simulations of membrane transport and membrane-based  process operation.

Prof. Dr. Peter Czermak
Prof. Dr. Stefan Panglisch
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Membranes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (4 papers)

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Research

17 pages, 2053 KiB  
Article
Predicting Water Flux in Forward Osmosis with Unknown Feed Solution Composition: An Empirical Approach Based on Thermodynamical Properties
by Bastian Greisner, Dieter Mauer, Frank Rögener and André Lerch
Membranes 2023, 13(4), 427; https://doi.org/10.3390/membranes13040427 - 12 Apr 2023
Viewed by 1481
Abstract
This study investigated the predictability of forward osmosis (FO) performance with an unknown feed solution composition, which is important in industrial applications where process solutions are concentrated but their composition is unknown. A fit function of the unknown solution’s osmotic pressure was created, [...] Read more.
This study investigated the predictability of forward osmosis (FO) performance with an unknown feed solution composition, which is important in industrial applications where process solutions are concentrated but their composition is unknown. A fit function of the unknown solution’s osmotic pressure was created, correlating it with the recovery rate, limited by solubility. The osmotic concentration was derived and used in the subsequent simulation of the permeate flux in the considered FO membrane. For comparison, magnesium chloride and magnesium sulfate solutions were used since these show a particularly strong deviation from the ideal osmotic pressure according to Van’t Hoff and are, thus, characterized by an osmotic coefficient unequal to 1. The simulation is based on the solution–diffusion model with consideration of external and internal concentration polarization phenomena. Here, a membrane module was subdivided into 25 segments of equal membrane area, and the module performance was solved by a numerical differential. Experiments in a laboratory scale for validation confirmed that the simulation gave satisfactory results. The recovery rate in the experimental run could be described for both solutions with a relative error of less than 5%, while the calculated water flux as a mathematical derivative of the recovery rate showed a bigger deviation. Full article
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21 pages, 1374 KiB  
Article
Membrane-Based Solvent Exchange Process for Purification of API Crystal Suspensions
by Fatima Anjum, Maximilian Wessner and Gabriele Sadowski
Membranes 2023, 13(3), 263; https://doi.org/10.3390/membranes13030263 - 23 Feb 2023
Cited by 2 | Viewed by 1880
Abstract
Bottom-up approaches to producing aqueous crystal suspensions of active pharmaceutical ingredients (APIs), such as anti-solvent crystallisation, are gaining interest as they offer better control over surface properties compared to top-down approaches. However, one of the major challenges that needs to be addressed is [...] Read more.
Bottom-up approaches to producing aqueous crystal suspensions of active pharmaceutical ingredients (APIs), such as anti-solvent crystallisation, are gaining interest as they offer better control over surface properties compared to top-down approaches. However, one of the major challenges that needs to be addressed is the removal of organic solvents after the crystallisation step due to strict limitations regarding human exposure. Within this work, we investigated a process concept for the removal of solvent (i.e., ethanol) from the API crystal suspension using membrane-based diafiltration. A four-stage diafiltration process successfully reduced the ethanol concentration in the API (here, naproxen) crystal suspension below 0.5 wt% (the residual solvent limit as per ICH guidelines) with a water consumption of 1.5 g of added water per g of feed. The solvent exchange process had no negative influence on the stability of the crystals in suspension, as their size and polymorphic form remained unchanged. This work is a step towards the bottom-up production of API crystal suspension by applying solvent/anti-solvent crystallisation. It provides the proof of concept for establishing a process of organic solvent removal and offers an experimental framework to serve as the foundation for the design of experiments implementing a solvent exchange in API production processes. Full article
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12 pages, 3097 KiB  
Article
Electrodialysis for the Concentration of Lithium-Containing Brines—An Investigation on the Applicability
by Frank Rögener and Lena Tetampel
Membranes 2022, 12(11), 1142; https://doi.org/10.3390/membranes12111142 - 15 Nov 2022
Cited by 1 | Viewed by 2215
Abstract
The importance of lithium as a raw material is steadily increasing, especially in the growing markets of grid energy and e-mobility. Today, brines are the most important lithium sources. The rising lithium demand raises concerns over the expandability and the environmental impact of [...] Read more.
The importance of lithium as a raw material is steadily increasing, especially in the growing markets of grid energy and e-mobility. Today, brines are the most important lithium sources. The rising lithium demand raises concerns over the expandability and the environmental impact of common mining techniques, which are mainly based on the evaporation of brine solutions (Salars) in arid and semiarid areas. In this case, much of the water contained in the brine is lost. Purification processes lead to further water losses of the ecosystems. This calls for new and improved processes for lithium production; one of them is electrodialysis (ED). Electrodialysis offers great potential in accessing lithium from brines in a more environmentally friendly way; furthermore, for the recovery of lithium from spent lithium-ion batteries (LIB), electrodialysis may become a vital technology. The following study focused on investigating the effect of varying brine compositions, different ED operation modes, and limiting factors on the use of ED for concentrating lithium-containing brine solutions. Synthetic lithium salt solutions (LiCl, LiOH) were concentrated using conventional ED in batch-wise operation. While the diluate solution was exchanged once a defined minimum concentration was reached, the concentrate solution was concentrated to the respective maximum. The experiments were conducted using a lab-scale ED-plant (BED1-3 from PCCell GmbH, Germany). The ion-exchange membranes used were PCSK and PCSA. The treated solutions varied in concentration and composition. Parameters such as current density, current efficiency, and energy requirements were evaluated. ED proved highly effective in the concentration of lithium salt solutions. Lithium chloride solutions were concentrated up to approximately 18-fold of the initial concentration. Current efficiencies and current densities depended on voltage, concentration, and the composition of the brine. Overall, the current efficiencies reached maximum values of around 70%. Furthermore, the experiments revealed a water transport of about 0.05 to 0.075% per gram of LiCl transferred from the diluate solution to the concentrate solution. Full article
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14 pages, 2105 KiB  
Article
A Combined Ultrafiltration/Diafiltration Process for the Purification of Oncolytic Measles Virus
by Daniel Loewe, Hauke Dieken, Tanja A. Grein, Denise Salzig and Peter Czermak
Membranes 2022, 12(2), 105; https://doi.org/10.3390/membranes12020105 - 18 Jan 2022
Cited by 4 | Viewed by 3384
Abstract
Measles virus (MV) is an important representative of a new class of cancer therapeutics known as oncolytic viruses. However, process intensification for the downstream purification of this fragile product is challenging. We previously found that a mid-range molecular weight cut-off (300 kDa) is [...] Read more.
Measles virus (MV) is an important representative of a new class of cancer therapeutics known as oncolytic viruses. However, process intensification for the downstream purification of this fragile product is challenging. We previously found that a mid-range molecular weight cut-off (300 kDa) is optimal for the concentration of MV. Here, we tested continuous and discontinuous diafiltration for the purification of MV prepared in two different media to determine the influence of high and low protein loads. We found that a concentration step before diafiltration improved process economy and MV yield when using either serum-containing or serum-free medium. We also found that discontinuous diafiltration conferred a slight benefit in terms of the permeate flow, reflecting the repetitive dilution steps and the ability to break down parts of the fouling layer on the membrane. In summary, the combined ultrafiltration/diafiltration process is suitable for the purification of MV, resulting in the recovery of ~50% infectious virus particles with a total concentration factor of 8 when using 5 diavolumes of buffer. Full article
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