An experimental study of helically stamped ceramic microfiltration membranes using bentonite suspensions

New geometries of zirconia and titania membranes were shown to enhance perm eate flux during tangential filtration. The modified membrane surface acts as an integrated turbulence promoter while the system is free from vibratio n or any other problem inherent to the addition either of turbulence promot er or a complementary device as for pulsed feed flow or rotating membranes. The aim of this work was to investigate the influence of the helical relie f on permeate flux during bentonite suspension filtration and the potential application of these new membranes for an industrial development. As with a classical smooth membrane, cake filtration occurred, but stamped membrane s were proved to reduce polarisation concentration, and to increase mass tr ansfer coefficient as well. Variations of the helical relief thread width a nd thickness, and the effect of helix direction inversions were investigate d. As regard with classical smooth membranes, stamped membranes from 125 to 380 mm long and membranes with inner diameters ranging from 5 to 16.65 mm were found to improve permeate flux in a comparable way, and some of the co nfigurations remained competitive from an energetic approach. Moreover, for a given membrane length, commercial multichannel membrane performances wer e surpassed by stamped membranes since the permeate flux was multiplied by factors up to 2.5 and 4, respectively. (C) 2001 Elsevier Science B.V. All r ights reserved.