THE EFFECTS OF OSMOTIC-PRESSURE AND FOULING DURING A CONCENTRATION PROCESS OF BSA SOLUTIONS BY ULTRAFILTRATION

The contribution of membrane fouling and osmotic pressure on permeate flux decline and reduction was investigated during a series of ultrafi ltration experiments of BSA solutions in a plate and frame tangential flow filtration unit equipped with a flat-sheet polysulfone membrane o f 10,000 MWCO. Five concentrations, namely 4, 8, 18, 43 and 88 kg/m(3) , were investigated in the order given. The osmotic pressure-adsorptio n model was selected for the determination of both contributions. The results show that the flux decline is determined by membrane fouling w hile flux reduction is controlled by membrane fouling and osmotic pres sure at earlier stages and by osmotic pressure at later stages of the process.