| Abstract: | Three sets of ultrafiltration (UF) membranes were prepared containing the following proportions (w/w) of polysulfone and dimethylacetamide: 14.5/85.5, 15.0/85.0 and 15.5/84.5. The membranes were characterized in terms of water flux, molecular weight (MW) cut-off, fouling, average pore size and ratio of pore surface area to membrane area. Membrane water flux was found to decrease as the polysulfone concentration or membrane thickness was increased. Scanning electron microscopy showed an asymmetric pore structure and indicated that the variation in water flux between membrane sets were probably due to differences in the number of pores per unit membrane area and not to differences in pore diameter. The MW cut-off for all the membranes was found to be close to 66 kD. The permeate flux for standard proteins decreased with increasing protein MW. A decrease in water flux was also observed after the UF runs; this could be explained by membrane fouling. Defatted waste tuna broth, which was obtained from a fish canning plant as steam condensate after autoclaving fresh tuna, was ultrafiltered using the prepared membranes. The rejection coefficient for either protein or carbohydrate solute of the tuna broth was approximately 54.5% while solute recovery was about 90%. The ultrafiltered broth had negligible turbidity and odor. |
