Critical flux of gum arabic: Implications for fouling and fractionation performance of membranes

•The critical flux of 2 wt% gum arabic measured using 3 pore sizes of polysulfone membrane.•Values were 27, 10 and 22 LMH for 0.1, 0.5 and 0.8 μm PS membranes, respectively.•Critical flux increased with increasing cross flow velocity.•Performance of membranes assessed both above and below the critical flux.

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.