My. Jaffrin et al., EFFECT OF ETHANOL ON ULTRAFILTRATION OF BOVINE ALBUMIN SOLUTIONS WITHORGANIC MEMBRANES, Journal of membrane science, 124(2), 1997, pp. 233-241
This paper investigates the ultrafiltration of albumin-ethanol solutio
ns on polysulfone hollow fiber membranes with 30 kDa cut-off. The aim
is to identify the mechanisms responsible for the observed permeate fl
ux reduction in presence of ethanol. The variations of permeate flux w
ith transmembrane pressure and wall shear rate fit the usual pattern o
f flux limitation by concentration polarization. Thus, although ethano
l significantly increases the permeate viscosity, the data show that t
he flux decrease is not a direct consequence of the viscosity increase
but rather due to reduced albumin diffusivity which decreases the bac
k transport to the bulk solution. The specific resistance of the album
in layer on the membrane was found to be unaffected by the presence of
ethanol. However the fouling potential of our solutions was found to
be significantly increased by the addition of ethanol. Thus the observ
ed flux reduction due to ethanol seems to be explained by a combinatio
n of a thicker polarization layer caused by reduced back transport and
increased membrane fouling. A 10% increase in filtrated volume can be
obtained by imposing periodic retrofiltrations which decrease fouling
.