Analysis of permeate flux by hyperbolic-tangent model for ultrafiltration in hollow-fiber membrane modules

A correlation equation of permeate flux for membrane ultrafiltration of a dilute polymer solution in hollow-fiber membrane modules, has been derived based on the hyperbolic tangent model with consideration of the declination of transmembrane pressure along the axial direction in the hollow fibers. The results show that the validity of correlation prediction from the experimental data increases as the feed velocity decreases, or when the solute concentration increases. It is believed that correlation prediction may be improved if the exact pressure distribution is employed and more experimental data are used to correlate the equation for the proportion constant in this model.