Biodegradable Nanofiber Membrane with Designed Beaded Structure for High-Efficiency Oil–Water Separation

Membrane separation technology has been extensively applied to treat oily effluent given its high performance and ease of operation. However, conventional polymer membranes are resistant to natural degradation after use, leading to severe environmental concerns. Consequently, the development of biodegradable membranes that combine satisfactory oil–water separation performance with ecological safety has emerged as a critical research priority. In this work, we fabricated a biodegradable membrane consisting of chitosan (CS), sodium methacrylate (SMa) and polyvinyl alcohol (PVA) via electrospinning, with anionic super-hydrophilic polyacrylamide (PAM) incorporated to enhance wettability. No toxic chemicals were used throughout the fabrication process. The resulting membrane with an interpenetrating network and beaded structure not only rendered the crosslinked nanofiber more hydrophilic but also improved the porosity of membranes, which significantly enhanced the separation performance and fouling resistance of the membrane. Specifically, the CS/PVA/SMa-PAM membrane achieved a separation flux of 2.7 × 10⁴ L·m⁻²·h⁻¹·bar⁻¹ for oil–water emulsions. After 20 emulsion separation cycles, the flux of the modified membrane was stable at 2.5 × 10⁴ L·m⁻²·h⁻¹·bar⁻¹. Benefiting from its excellent anti-fouling properties, high separation efficiency, eco-friendly biodegradability, and toxic-reagent-free fabrication, the as-prepared CS/PVA/SMa-PAM membrane offers a promising and sustainable option for oily wastewater treatment.