Lf. Song et M. Elimelech, THEORY OF CONCENTRATION POLARIZATION IN CROSS-FLOW FILTRATION, Journal of the Chemical Society. Faraday transactions, 91(19), 1995, pp. 3389-3398
Citations number
13
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
A novel theory is developed for concentration polarization of non-inte
racting particles in crossflow-filtration systems. This theory reveals
that the extent of concentration polarization, as well as the behavio
ur of the permeate flux, are characterized by an important dimensionle
ss filtration number (N-F = 4 pi a(p)(3) Delta P/3kT). There is a crit
ical value of the filtration number for a given suspension and operati
onal conditions. When the filtration number is smaller than the critic
al value, a polarization layer exists directly over the membrane surfa
ce and the wall particle concentration is determined by the pressure a
nd temperature. At higher filtration numbers, a cake layer of retained
particles forms between the polarization layer and the membrane surfa
ce. Mathematical models are constructed for both cases and analytical
solutions for the permeate flux are derived. An increase in permeate f
lux with increasing pressure is predicted for all operational conditio
ns.