CORRELATIONS OF FILTRATION FLUX ENHANCED BY ELECTRIC-FIELDS IN CROSS-FLOW MICROFILTRATION

The steady state filtration flux in electrically-enhanced crossflow mi crofiltration is estimated using a correlation equation proposed for s everal kinds of suspensions. Baker's yeast and Rhodotorula glutinis we re used as model samples of microbial cells, and PMMA particles were u sed as samples of non-living solds. Application of the electric field in crossflow microfiltration is a useful method for improving the filt ration flux of these samples. High flux levels for the cells were achi eved when an electric field above 3000 V/m was applied. The effect of the electric field in increasing the filtration flux of the steady sta te was analyzed theoretically using a force balance model where the vi scous drag force, F-J, the electrophoretic force, F-E, and the re-entr aining force, F-B, were considered to act on a particle on the membran e surface under a steady state of filtration, respectively. From force balance analysis, it is found that on application of an electric fiel d, the electro-osmotic effect on be neglected in the present study, so that the filtration flux of the steady state, J(ES), can be presented by, J(ES) = UEPE + J(OS) where U-EP is the electrophoretic mobility o f particles and E is the electric field applied. J(OS) is the filtrati on flux in the absence of an electric field, which is correlated with the operating parameters for suspensions tested.