The role of membrane pressure in reverse osmosis

Liquid transport occurs through reverse osmosis membranes as a result of an applied pressure differential. The pressure within the membrane continuum is an important thermodynamic parameter in the formulation of solution-diffusion models for this process. It is shown that this membrane pressure is the same throughout the membrane for supported flat and tubular membranes and for hollow fibers. The use of this parameter in calculating the induced concentration differential is discussed.