ABSTRACT
The solution-diffusion model was outlined in Chapter 5 as a transport model for reverse osmosis. Models other than the solution-diffusion model exist, the most typical ones being the irreversible thermodynamic model [177]—[181] and the fine-pore model [182]—[187]. The fine-pore model was developed assuming the presence of open micropores on the active surface layer of the membrane through which the mass transport occurs. In contrast, the presence of pores is not assumed in the solution-diffusion model, and the mass transport is considered to occur through a film without heterogeneous structure. In the preferential sorption-capillary flow model proposed by Sourirajan [51], the influence of the interaction force between the solute, solvent, and membrane material on the flow of mass through the open capillaries is considered. Because the radii of the micropores that are present in the reverse osmosis membrane are so small that the flowing mass cannot escape from the influence of the interaction force exerted from the membrane material, Sourirajan’s model seems to be the closest to reality. Later a quantitative expression was given to the above model by various authors, in developing the surface force-pore flow model [188–207].
