Document Type

Article

Publication Date

1-11-2024

Keywords

membrane process, membrane transport, modeling, simulation, membrane modeling, membrane formation

Abstract

Today, membranes play an increasing role in separation processes across a wide range of industries, including water treatment, biomedical applications, bioseparations, and gas separations (Yeom et al., 2022). Numerous different membrane types exist, which can be broadly categorized as either porous or non-porous, where pores may be or may not be filled with a separate phase from the bulk solvent and membrane phases. In addition, various driving forces exist - pressure, concentration, electric field, etc.—that lead to transport across the membrane. For a porous membrane, solute transport is usually governed by convective flow through the pores. Micron-sized pores are used to reject particles such as cells and cell debris while at the other end of the size range, nanoscale pores act as molecular sieves, selectively allowing smaller molecules to pass through. Nanoscale domains in non-porous (dense) membranes control separation selectivity and permeability by manipulating solute distribution and diffusivity. These nanostructures can also influence solute behavior, like adsorption/desorption at membrane interfaces. At intermediate pore sizes, convection and diffusion may both play a significant role in solute transport as is often observed for nanofiltration membranes. In addition surface properties such as charge can have a significant effect on performance. Simulation and modeling play an increasingly important role in the design of these separation processes. Computational methods offer the possibility of enabling rational design of new membranes and membrane processes (Kancherla et al., 2021; Samei and Raisi, 2022), supporting the optimization and understanding of complex membrane-based systems. They can be used to examine molecular interactions that lead to adsorption and desorption of species as well as fouling. This can guide the development of new membranes leading to improved performance. Nonetheless, the simulation and modeling of membrane separation processes presents a range of formidable challenges that demand our attention. In this contribution, we delve into the existing hurdles relating to simulation and modeling. Our aim is to highlight these issues and emphasize the need for increased focus by researchers engaged in the simulation and modeling field. This article is divided into three sections. The first focuses on the membrane casting process and modeling of membrane structure. The second section discusses simulation of separations using dense membranes, which includes, gas separations, pervaporation, and perstraction. The final section discusses separations involving porous membranes. Some membranes, such as those used for reverse osmosis, forward osmosis, dialysis, etc. may be considered at the boundary between dense and porous membranes and have been included with dense membranes.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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