Effects of Air-Sparging on the Filtration Flux and Cake Properties in Cross-Flow Microfiltration of Size-Distributed Fine Particles

The effect of air-sparging on the performance of cross-flow microfiltration of size-distributed fine particles is studied. The filtration flux and cake properties under various air velocities are measured and discussed. A higher air velocity leads to a lighter cake due to the higher shear stress acting on the membrane surface, especially under a bubble flow regime. However, the decrease in deposited particle size causes higher average specific cake filtration resistance as well as lower pseudo-steady filtration flux. A force balance model is employed to grasp the particle deposition on the membrane surface. The drag forces due to fluid flows play a major role in determining the particle deposition probability. The interparticle forces are dominant for submicron particles, while the inertial lift and gravitational force increase the weights for those particles larger than 10 µm. The occurrences of a minimum deposited probability for 0.2–0.3 µm particles and a maximum value for ca 2 µm particles ca...