Surface-engineered polyethersulfone membranes with inherent Fe-Mn bimetallic oxides for improved permeability and antifouling capability.

In recent years, bimetallic oxide nanoparticles have garnered significant attention owing to their salient advantages over monometallic nanoparticles. In this study, FeO-MnO nanoparticles were synthesized and used as nanomodifiers for polyethersulfone (PES) ultrafiltration membranes. A NIPS was used to fabricate asymmetric membranes. The effect of nanoparticle concentration (0-1 wt.%) on the morphology, roughness, wettability, porosity, permeability, and protein filtration performance of the membranes was investigated. The membrane containing 0.25 wt% nanoparticles exhibited the lowest water contact angle (67°) and surface roughness (10.4 ± 2.8 nm) compared to the other membranes. Moreover, this membrane exhibited the highest porosity (74%) and the highest pure water flux (398 L/m h), which was 16% and 1.9 times higher than that of the pristine PES membrane. The modified PES membranes showed an improved antifouling ability, especially against irreversible fouling. Bovine serum albumin protein-based dynamic five-cycle filtration tests showed a maximum flux recovery ratio of 77% (cycle-1), 67% (cycle-2), and 65.8% (cycle-5) for the PES membrane containing 0.25 wt% nanoparticles. Overall, the biphasic FeO-MnO nanoparticles were found to be an effective nanomodifier for improving the permeability and antifouling ability of PES membranes in protein separation and water treatment applications.