Separation of solutes with different diffusivities in a hybrid membrane cell comprising semi and fully permeable membranes

Abstract

A hybrid separation membrane cell comprising semi and fully-permeable membrane sections is employed to fractionate solutions containing a solvent and two solutes, namely BSA and dextran. The separation technique takes advantage of the difference between diffusivities of the solutes. The semi-permeable membranes are permeable to the solvent and impermeable to both solutes and the fully-permeable membranes are permeable to all components. Numerical simulations are used to understand the role of the physical mechanisms involved in the process and to determine the influence of the cell characteristics (e.g. number of sections), solute properties (e.g. diffusivities) and operational parameters (e.g., velocity of the solvent stream, velocity of the concentrate stream). For the solutes in study, BSA and Dextran, the separation depends also on the physical properties, like viscosity of the solution, and osmotic pressure of the solutes. These are concentration dependent properties and so they change along the cell. This numerical code is presently under development.