Modeling of transient permeate flux in cross-flow membrane filtration incorporating multiple particle transport mechanisms


Journal Article

Dominant mechanisms of particle transport in cross-flow membrane filtration are unified to obtain a generalized model for time-dependent permeate flux. The unified model extends an earlier model based on shear-induced diffusion and a concentrated flowing layer to include Brownian diffusion and inertial lift. It is applicable over a broad range of contaminant sizes encompassing macromolecules, colloidal and fine particles, and large particles. The combined theory predicts an unfavorable particle size, of the order of 10-1 μm, where the net back-transport away from the membrane attains a minimum, leading to maximum cake growth. For the system simulated in this work, this implies minimum permeate fluxes in the size range of 0.01-0.1 μm, depending on the operating time. Inside-out hollow-fiber geometry is predicted to be favorable for feed suspensions with small particles and/or low concentrations which form thin resistive cakes. However, larger particles, which form thick cakes, may result in reduced surface area available for filtration due to curvature effects in inside-out membranes, making the slit or outside-in geometry more favorable for these particles. Fine particles (< 0.1 μm) are predicted to demonstrate mass-transport limited behavior. For larger particles, different combinations of fiber radius and cross-flow velocity, resulting in the same shear rate, demonstrate different permeate fluxes.

Full Text

Duke Authors

Cited Authors

  • Sethi, S; Wiesner, MR

Published Date

  • December 10, 1997

Published In

Volume / Issue

  • 136 / 1-2

Start / End Page

  • 191 - 205

International Standard Serial Number (ISSN)

  • 0376-7388

Digital Object Identifier (DOI)

  • 10.1016/S0376-7388(97)00168-3

Citation Source

  • Scopus