Ultrafiltration flux behavior

To illustrate the behavior of the ultrafiltration flux, we here adopt Michaels model of gel layer formation. As was done for reverse osmosis, let us again consider the geometry of a two-dimensional parallel plate channel with fully developed flow. Moreover, to simplify the presentation, we examine only the limiting-flux problem. 

Modification of polymeric membrane materials through incorporation of hydrophi-licity results in membranes with low fouling behavior and high flux. Thus, literature presents sulfonated polysulfone/cellulose acetate blends applied in various compositions for obtaining ultrafiltration membranes, where their performance is improved by the inclusion of polyethyleneglycol into the casting solution as a nonsolvent additive in various concentrations. In this way, total polymer concentration, cellulose acetate, sulfonated polysulfone polymer blend composition, additive concentration, and their compatibility with polymer blends are optimized [133]. 

Figure 6.3.26. Ultrafiltration, (a) UF in a batch cell macrosolute concentration profile infeed side (b) Piston driven UF in a batch cell bulk flow parallel to the force, (c) Observed behavior ofsolvent flux vs. AP in macrosolute ultrafiltration. For an explanation of (l)-(4), see the text.

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