An assessment of depolarisation models of crossflow microfiltration by direct observation through the membrane

✍ Scribed by H Li; A.G Fane; H.G.L Coster; S Vigneswaran

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 415 KB
• Volume: 172
• Category: Article
• ISSN: 0376-7388
• DOI: 10.1016/s0376-7388(00)00334-3

✦ Synopsis

Direct observation through the membrane (DOTM) has been applied to monitor the deposition of supermicron particles (3-12 m) on microfiltration membranes and to identify the critical fluxes for cake formation as a function of crossflow. The observed critical fluxes are compared with predictions from various models. It is found that the shear-induced diffusivity model predicts acceptable critical flux for latex particles of 6.4 m and yeast (5 m). A modified shear-induced diffusivity model for dilute suspensions predicts closely for yeast and latex (6.4 and 11.9 m), with the exception of 3 m latex particles.

The shear-induced hydrodynamic diffusivity model over-predicts the critical fluxes by a factor of about 2. The inertial lift model under-predicts the critical fluxes for the microfiltration of all the particles. This study also suggests that for smaller particles (3 m latex and 4 m algae), in addition to hydrodynamic effects, other factors such as surface charge may need to be considered for particle back-transport mechanisms.