Abstract
A mathematical model of membrane distillation of aqueous solutions of organic substances (alcohols) using hydrophilic membranes has been developed. The membrane is modeled as a capillary-porous body all the pores of which are rectilinear capillaries of the same length and radius. The study was carried out for moderately intense processes, when the radius of curvature of the meniscus of a cylindrical pore exceeds the radius of the capillary, that is, there is no deepening of the evaporation front. An analytical formula was obtained, its parametric study was carried out and the extreme behavior of the separation coefficient of the most membrane-trapped component of the mixture was revealed depending on the concentration of solvent vapor in the blowing gas stream, which qualitatively corresponds to the behavior of this coefficient during the pervaporation of aqueous ethanol solutions using crosslinked hydrophilic pullulane membranes and hydrophilic chitosan membranes, as well as chitosan membranes crosslinked with glutaraldehyde.