Sk. Karode, A predictive model for ultrafiltration: Combination of osmotic pressure model and irreversible thermodynamics, SEP SCI TEC, 36(12), 2001, pp. 2659-2676
An unsteady state model for ultrafiltration that describes transport within
the pores of the ultrafiltration membrane is presented. The new, improved
model combines the osmotic pressure model for transport in the polarization
layer and the irreversible thermodynamics approach. The model is capable o
f simultaneously predicting 1) the permeate flux, 2) the permeate concentra
tion, and 3) the concentration at the membrane feed surface when all the tr
ansport parameters are fixed. The model data are comparable to the experime
ntal data cited in the literature. Model simulations conducted by varying 1
parameter while the others are kept constant show that the entire range of
observed transmissions is a function of permeate flux. For certain paramet
er values, the model predicts observed transmission greater than unity. Hen
ce, in principle, an ultrafiltration system in which the product of interes
t is concentrated in the permeate stream can be designed. The model also co
rrectly predicts the experimental observation that the magnitude of observe
d transmission that is greater than unity decreases as the feed concentrati
on increases.