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 ZrOz-TiOJcarbon. 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,) can be reduced by increasing the crossflow velocity on the membrane surface. Analysis by the resistances-in-series model showed that, R, decreases with flow velocity with exponents of 0.49 and 0.99 for the laminar system and the turbulent system, respectively.
Separation Science and Technology 32(16), pp.2623-2640