Special Issue "New Phenomenological Findings in RO/NF-Membrane Applications 2.0"

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

Deadline for manuscript submissions: closed (31 October 2022) | Viewed by 1730

Special Issue Editor

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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Special Issue Information

Dear Colleagues, 

As the Guest Editor of the Special Issue of Membranes titled "New Phenomenological Findings in RO/NF applications”, I am honored to invite you to submit your next research paper or review article for inclusion in this Special Issue.

In this Special Issue, we aim to provide a forum for publishing papers that advance our understanding of specific separation phenomena in a variety of applications. 

Our focus in this issue is in the area of new insights and separation properties of RO/NF membranes in isolating and concentrating systems at high osmotic pressures that require high operating pressures of up to 64 bar or even higher to be applied during such applications. Publications are expected to cover the broad aspects of the science and technology of the separation mechanism, selectivity, and unusual rejection phenomena in chemical, pharmaceutical, and food industry applications. The articles in this issue will also aim to illustrate some of the current developments in the field. 

Energy consumption in industrial processes is already a major concern today and will continue to be in the near future. Here, membranes offer an energy-saving alternative to conventional separation processes with phase changes in order to enrich or concentrate the substances to be recovered as much as possible. 

In the isolation and recovery of dissolved products from dilute solutions, high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO) are considered to be the most promising, as they not only enrich substances without phase change with the energy input required in the process, but in particular, they also allow them to be obtained at higher concentrations. 

In this Special Issue, original research articles and reviews are welcome. 

We look forward to receiving your contributions.

Prof. Dr. Wolfgang Samhaber
Guest Editor

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.


  • nanofiltration (NF)
  • reverse osmosis (RO)
  • concentrating
  • high pressures
  • selective transport

Published Papers (1 paper)

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16 pages, 4634 KiB  
Feasibility of Poly (Vinyl Alcohol)/Poly (Diallyldimethylammonium Chloride) Polymeric Network Hydrogel as Draw Solute for Forward Osmosis Process
Membranes 2022, 12(11), 1097; https://doi.org/10.3390/membranes12111097 - 03 Nov 2022
Cited by 1 | Viewed by 1182
Forward osmosis (FO) has been identified as an emerging technology for the concentration and crystallization of aqueous solutions at low temperatures. However, the application of the FO process has been limited due to the unavailability of a suitable draw solute. An ideal draw [...] Read more.
Forward osmosis (FO) has been identified as an emerging technology for the concentration and crystallization of aqueous solutions at low temperatures. However, the application of the FO process has been limited due to the unavailability of a suitable draw solute. An ideal draw solute should be able to generate high osmotic pressure and must be easily regenerated with less reverse solute flux (RSF). Recently, hydrogels have attracted attention as a draw solution due to their high capacity to absorb water and low RSF. This study explores a poly (vinyl alcohol)/poly (diallyldimethylammonium chloride) (PVA-polyDADMAC) polymeric network hydrogel as a draw solute in forward osmosis. A low-pressure reverse osmosis (RO) membrane was used in the FO process to study the performance of the hydrogel prepared in this study as a draw solution. The robust and straightforward gel synthesis method provides an extensive-scale application. The results indicate that incorporating cationic polyelectrolyte poly (diallyldimethylammonium chloride) into the polymeric network increases swelling capacity and osmotic pressure, thereby resulting in an average water flux of the PVA-polyDADMAC hydrogel (0.97 L m−2 h−1) that was 7.47 times higher than the PVA hydrogel during a 6 h FO process against a 5000 mg L−1 NaCl solution (as a feed solution). The effect of polymer and cross-linker composition on swelling capacity was studied to optimize the synthesized hydrogel composition. At 50 °C, the hydrogel releases nearly >70% of the water absorbed during the FO process at room temperatures, and water flux can be recovered by up to 86.6% of the initial flux after 12 hydrogel (draw solute) regenerations. Furthermore, this study suggests that incorporating cationic polyelectrolytes into the polymeric network enhances FO performances and lowers the actual energy requirements for (draw solute) regeneration. This study represents a significant step toward the commercial implementation of a hydrogel-driven FO system for the concentration of liquid-food extract. Full article
(This article belongs to the Special Issue New Phenomenological Findings in RO/NF-Membrane Applications 2.0)
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