Membrane fouling caused by protein-like organic matter is a major challenge during the application of ultrafiltration technology in food wastewater treatment. In this work, 0.3 mM hydrogen peroxide (H2O2) and 0.15 mM Fe2+ were added to three typical protein-rich wastewaters, and macro- and microanalyses were performed to unravel their influence on the protein fouling of membranes. The results showed that for bovine serum protein, lysozyme or soya protein, the membrane flux decline rate could be reduced by more than 50%, and the flux recovery rate could be improved by 60% after pre-treatment with H2O2&Fe2+. This is because the small quantity of Fe2+&H2O2 could induce the Fenton reaction without pH pre-adjustment, which was accompanied by the occurrence of oxidation and coagulation. Then, the synergistic effect of oxidation and coagulation promoted protein molecules to clump together to form large aggregates, while the adhesion forces of proteins at the membrane surface were weakened by oxidation. These factors eventually mitigated the deposition rate of protein onto the membrane surface and resulted in a more porous and loose fouling layer. Moreover, the iron ions added could effectively bind with protein molecules and be intercepted by the ultrafiltration membrane, which avoided secondary pollution.
