No abstract

A flux-stepping method was used to determine the critical flux of 2 wt% gum arabic using flat sheet polysulfone membranes. These were found to be 27 L m -2 h -1 , 10 L m -2 h -1 and 22 L m -2 h -1 for 0.1, 0.5 and 0.8 µm polysulfone membranes, respectively. Increasing the cross flow velocity was found to raise the critical flux, although the effect diminished at higher velocities. These values were then used to assess the fouling and the fractionation performance of the three membranes above and below their critical fluxes.