Microfiltration of deforming oil droplets on a slotted pore membrane and sustainable flux rates

Oil droplets from an emulsion were filtered using a slotted pore membrane with a 4 m slot width and 400 m slot length. Droplets up to 15 m in diameter were filtered at various flux rates (200–1200 l m−2 h−1) using oscillatory membrane microfiltration. Surface shear rates at the membrane of various intensities (0, 1200, 3200 and 8100 s−1) were applied and the effect on permeate flux rate and trans-membrane pressure were investigated. Near constant filtration flux was obtained for all the tests. Without shear the trans-membrane pressure increased quickly, but at the highest shear rate (8100 s−1) nearly constant trans-membrane pressure and flux rate were observed and may be described as sustainable, or weak form of critical flux. A filtration membrane blocking model was used to investigate the filtration and identify when sustainable, or critical, flux was achieved.