Models for Facilitated Transport Membranes: A Review

Abstract

Facilitated transport membranes are particularly promising in different separations, as they are potentially able to overcome the trade-off behavior usually encountered in solution-diffusion membranes. The reaction activated transport is a process in which several mechanisms take place simultaneously, and requires a rigorous theoretical analysis, which unfortunately is often neglected in current studies more focused on material development. In this work, we selected and reviewed the main mathematical models introduced to describe mobile and fixed facilitated transport systems in steady state conditions, in order to provide the reader with an overview of the existing mathematical tools. An analytical solution to the mass transport problem cannot be achieved, even when considering simple reaction schemes such as that between oxygen (solute) and hemoglobin (carrier) ( A + C ⇄ A C ), that was thoroughly studied by the first works dealing with this type of biological facilitated transport. Therefore, modeling studies provided approximate analytical solutions and comparison against experimental observations and exact numerical calculations. The derivation, the main assumptions, and approximations of such modeling approaches is briefly presented to assess their applicability, precision, and flexibility in describing and understanding mobile and fixed site carriers facilitated transport membranes. The goal is to establish which mathematical tools are more suitable to support and guide the development and design of new facilitated transport systems and materials. Among the models presented, in particular, those from Teramoto and from Morales-Cabrera et al. seem the more flexible and general ones for the mobile carrier case, while the formalization made by Noble and coauthors appears the most complete in the case of fixed site carrier membranes.

CO2 Desorption Performance from Imidazolium Ionic Liquids by Membrane Vacuum Regeneration Technology

“…In addition, from the viewpoint of industrialization, recent progress on transport properties of IL fluids and process design, as well as the assessment of IL-based processes, were addressed in some reviews [17,30,31], covering relevant studies on CO 2 capture and separation with conventional ILs, functionalized ILs, IL blending solvents, and IL-based membranes.…”

Crosslinked Facilitated Transport Membranes Based on Carboxymethylated NFC and Amine-Based Fixed Carriers for Carbon Capture, Utilization, and Storage Applications

“…As an alternative to conventional polymeric membranes, facilitated transport membranes (FTMs) have attracted attention because of the potential to achieve both high permeability and high selectivity [20,21]. FTMs selectively permeate CO 2 by adding to the transport of free CO 2 molecules an additional mechanism of facilitated diffusion through complexation with an agent incorporated in the membrane, named carrier [22][23][24][25], whereas gases such as H 2 , N 2 , and CH 4 will permeate exclusively by a solution-diffusion mechanism. For CO 2 separation, amine moieties represent a quite reasonable choice as carriers which was exploited in several works [26][27][28][29][30].…”

Various Techniques for Preparation of Thin‐Film Composite Mixed‐Matrix Membranes for CO2 Separation

“…These membranes have metal ions as a carrier with a distinct attraction route for the target of a gas molecule, and this interface regulates the sum of gas transport. It is expected that these membranes can be an effective method to attain high selectivity and permeability , .…”