Biomimetic “Flower-on-Fiber” Janus membrane with Z-scheme heterojunctions for synergistic oily wastewater remediation: Visible-light photocatalysis, unidirectional transport and dual-mode antibacterial activity

Biomimetic “flower-on-fiber” Janus membranes were engineered. • Achieved >99% emulsion separation and 97.4% TCH degradation under visible light. • Proposed Z-scheme supported by EPR/DFT boosts visible-light charge separation. • Asymmetric wettability enables unidirectional oil transport and “Janus boat” application. • Synergistic physical/photocatalytic mechanism confers 99.99% antibacterial rate. The remediation of complex industrial wastewater—characterized by the coexistence of emulsified oils, soluble organic micropollutants, and pathogenic bacteria—necessitates a paradigm shift from passive filtration to active, multifunctional interface engineering. To address this, a novel biomimetic “flower-on-fiber” Janus membrane was engineered via a sequential electrospinning and spray-deposition strategy. The membrane features a rationally designed asymmetric architecture, integrating a hydrophobic Z -scheme photocatalytic top-layer (BiOBr/ZnO/TiO 2 @PVDF) with a hydrophilic substrate (PAN@PEG). Molecular Dynamics (MD) simulations were used as qualitative support to examine the water/BiOBr interfacial behavior, indicating that water molecules tend to remain aggregated rather than spread on the BiOBr lattice. Consequently, the membrane achieved high-efficiency separation (>99%) of surfactant-stabilized water-in-oil emulsions with a superior flux of 2120 ± 119 L m −2  h −1 . Beyond physical separation, the constructed heterojunction promoted visible-light absorption and suppressed charge recombination. This endowed the membrane with exceptional “active” defense capabilities: a 97.4% degradation efficiency for tetracycline hydrochloride (TCH) and a 99.99% antibacterial rate against E. coli via a synergistic “physical puncture-photocatalytic oxidation” dual-mode mechanism. This work demonstrates a proof-of-concept Janus membrane platform that couples structural biomimicry with Z -scheme heterojunction engineering to integrate water-in-oil emulsion separation, visible-light-driven tetracycline degradation, and antibacterial activity against E. coli .