Permeate flux feed sources

TABLE 13.4 Permeate Flux for Different Feed Sources... 

The main problem in membrane usage for water purification is the fouling layer that adheres to the membrane. The source of the fouling layer is the different species existing in the feed water and their increased concentration next to the membrane wall. When water permeates through the membrane, all rejected species accumulate next to the membrane wall, their concentration increases in comparison to the bulk concentration, and the motion away from the membrane is controlled by diffusion to the bulk of flow against the flux of the water flowing to the membrane. 

The membrane permeation test measures the flux of drug across a synthetic membrane into an organic sink (permeate). For the test, a synthetic semipermeable membrane is used to separate the feed solution (i.e., simulated intestinal medium) and permeate (sink) solution (e.g., 80 % decanol and 20 % decane, by weight). Aliquots of permeate are taken at specific time points and the concentfation of drug is measured by HPLC. High flux indicates a formulation s ability to rapidly dissolve and source a high concentration of free drug. 

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