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ORIGINAL RESEARCH article

Front. Membr. Sci. Technol.
Sec. Membrane Transport, Modeling and Simulation
Volume 4 - 2025 | doi: 10.3389/frmst.2025.1513591

Transport in Reverse Osmosis Membranes: Observations and Comments on the Pore Flow Model versus the Solution-Diffusion Model

Provisionally accepted
Takeshi Matsuura Takeshi Matsuura 1*Michael D. Guiver Michael D. Guiver 2Woei Jye Lau Woei Jye Lau 3Ahmad Fauzi Ismail Ahmad Fauzi Ismail 3
  • 1 University of Ottawa, Ottawa, Ontario, Canada
  • 2 Tianjin University, Tianjin, China
  • 3 University of Technology Malaysia, Johor Bahru, Johor Darul Takzim, Malaysia

The final, formatted version of the article will be published soon.

    Sixty-four years have passed since the announcement of the cellulose acetate membrane for seawater desalination by Loeb and Sourirajan at UCLA on Aug 23, 1960. Reverse osmosis (RO) is now well established as a process for desalination of seawater, brackish water, as well as for wastewater treatment. The number of research papers on RO is growing. In contrast to the numerous publications on RO membrane preparation and applications, studies on transport mechanisms have been largely neglected. However, this changed recently when M. Elimelech's research group from Yale University published several papers challenging the applicability of the solution-diffusion (S-D) model. Especially, in the most recent paper published in 2024, they have shown seven reasons why the well-accepted S-D model appears to be wrong. It is interesting to note that, according to S. Sourirajan, one of the co-inventors of cellulose acetate RO membrane, their work was guided by the Preferential Sorption-Capillary Flow model.Moreover, he wrote that this pore model was based on the presence of a pure water layer at the salt solution-air interface, which could be predicted by the Gibbs Adsorption Isotherm. The purpose of this short communication is to present some observations and discussion in response to the 2024 paper published by Elimelech's group in Desalination journal. In addition, the Gibbs Adsorption Isotherm was revisited to examine if there is a pure water layer at the sodium chloride-cellulose acetate membrane interface.

    Keywords: Reverse osmosis, Solution-diffusion model, Gibbs adsorption isotherm, Preferential Sorption-Capillary Flow Model, Membrane desalination

    Received: 18 Oct 2024; Accepted: 07 Jan 2025.

    Copyright: © 2025 Matsuura, Guiver, Lau and Ismail. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Takeshi Matsuura, University of Ottawa, Ottawa, K1N 6N5, Ontario, Canada

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.