Resistance analyses for ultrafiltration in tubular membrane module

The resistance analyses for ultrafiltration of macromolecular solutions by the resistances-in-series model and the modified gel-polarization model, respectively, have been extended to the turbulent ultrafiltration system in this study. The experiments are carried out by ultrafiltrating dextran T500 solutions in a tubular membrane module with membrane material of ZrO2-TiO2/carbon. It is found that the permeate fluxes are predicted very well by these models for both laminar and turbulent systems, and the resistance caused by the concentration polarization/ gel layer (R-p) can be reduced by increasing the crossflow velocity on the membrane surface, Analysis by the resistances-in-series model showed that, R-p decreases with flow velocity with exponents of 0.49 and 0.99 for the laminar system and the turbulent system, respectively.