Effect of bubble size and frequency on the permeate flux of gas sparged ultrafiltration with tubular membranes

Gas sparged ultrafiltration experiments are performed using a tubular membrane module with solutions of dextran and human serum albumin (HSA) as the test media. Air is injected, in a controlled manner with the ability to adjust bubble size and frequency independently, into the membrane module to create a gas-liquid two-phase crossflow operation. The effects of bubble size and frequency on the permeate flux of the sparged ultrafiltration are studied experimentally. It is found that the permeate flux increases with the bubbling frequency in the examined range. The effect of bubble size on flux can be divided into two regions, an increasing region for smaller bubbles and a plateau region for larger slugs. The results are discussed on the basis of bubble wake hydrodynamics. (C) 1997 Elsevier Science S.A.