Antimicrobial and pressure resistant polysulfone blended ultrafiltration membranes with core-shell ZnO microspheres

摘要

Hybrid membranes prepared by blending antibacterial nanoparticles and organic materials are fascinating for creating novel filtration materials with improved properties such as excellent antimicrobial activity, good permeability and mechanical properties. In this study, composite zinc oxide microspheres with elaborate hollow structures were constructed as multi barrier layers for both effective release control and pressure resistance. Different polysulfone (PSF) membranes with competitive antimicrobial properties toward Staphylococcus aureus and Escherichia coli were synthesized by applying, single-shell ZnO microspheres (S membranes), core-shell ZnO microspheres (C1 membranes) and levodopa (dopa) coated core-shell ZnO microspheres (C2 membranes) via phase inversion with ZnO nanoparticles (Z membranes) for comparison. Since the rate of zinc ions diffusion can be limited due to the barriers created by the multi shells of hollow microspheres and adhesion layer with catechol and indole functional groups, the prepared polysulfone ultrafiltration membranes can keep good balance between structure and antimicrobial feature. In the filtration process, the novel blended membranes exhibited fascinating pure water flux at least two times higher than that of pure PSF membrane, and the rejection rate for BSA reached 91.2%. After two cycles of operation, they displayed excellent anti-fouling ability as well as long-term stability with little leakage of zinc ions. Moreover, as multi-layer structure can obviously improve the mechanical strength of colloids, the prepared membranes exhibited attractive pressure resistant ability which may effectively withstand harsh conditions in the practical pressure-driven process.