PHYSICOCHEMICAL INTERPRETATION OF THE BEHAVIOR OF A PRESSURE-DRIVEN MEMBRANE SEPARATION PROCESS.

In the pressure-driven membrane separation of binary aqueous solutions of aromatic hydrocarbons using asymmetric cellulose acetate membranes, the total solution flux is often significantly less than the pure water flux at the same pressure, even in the absence of significant osmotic pressures. This behavior can be explained using a simple model in which adsorbed solute reduces the area available for transport. Flux reduction can be correlated with composition using an adsorption isotherm, and the parameters obtained in that correlation are related to the physicochemical nature of the solute-solvent-membrane system.