Scope and limitations of the irreversible thermodynamics and the solution diffusion models for the separation of binary and multi-component systems in reverse osmosis process

Abstract

Reverse osmosis process is used in many industrial applications ranging from solute-solvent to solvent-solvent and gaseous separation. A number of theoretical models have been developed to describe the separation and fluxes of solvent and solute in such processes. This paper looks into the scope and limitations of two main models (the irreversible thermodynamics and the solution diffusion models) used in the past by several researchers for solute-solvent feed separation. Despite the investigation of other complex models, the simple concepts of these models accelerate the feasibility of the implementation of reverse osmosis for different types of systems and variety of industries. Briefly, an extensive review of these mathematical models is conducted by collecting more than 70 examples from literature in this study. In addition, this review has covered the improvement of such models to make them compatible with multi-component systems with consideration of concentration polarization and solvent-solute-membrane interaction.

Feed Spacer Geometries and Permeability Coefficients. Effect on the Performance in BWRO Spriral-Wound Membrane Modules

“…The performance of these three membranes wound with different feed spacer geometries was simulated. Solution-diffusion [26,27], which assumes that the membrane is nonporous (without imperfections), was the method of transport used. The theory is that transport through the membrane occurs as the molecule of interest dissolves in the membrane and then diffuses through the membrane.…”

Performance analysis of a medium-sized industrial reverse osmosis brackish water desalination plant

“…A thorough review of the open literature confirms several attempts of spiral wound RO modelling based on the principles of solution diffusion model and irreversible thermodynamic model [13][14][15][16][17]. The models developed are used to quantify the transport phenomenon of water and solute through the membrane.…”

A computational tool for designing BWRO systems with spiral wound modules

“…Solution-diffusion [31,32] was the method of transport used, since it is the most widely accepted and provides results close to the real behavior of these systems. Transport equations have used mean values of membrane elements, and pressure drop in the permeate as well as temperature changes along the RO systems have been disregarded.…”