Janus Nanofiber Antibacterial Membrane for Switchable Separation of Oil/Water Emulsions

Abstract

Treatment and recycling reuse of oily wastewater caused by offshore oil spill accidents and the discharge of food industry have become an urgent hot issue and promote the development of oil/water separation materials. However, the efficient separation of oily wastewater still remains a big challenge. Simple, low-cost, and easily scale-up processes for the fabrication of materials to effectively separate oil/water mixtures, especially stabilized emulsions, with high efficiency and that are durable in wastewater treatment are urgently desired. Herein, a scalable, lowcost, and antibacterial Janus AgNPs@PVA-co-PE (PVA, polyvinyl alcohol; PE, polyethylene) membrane was developed by spraying the hydrophilic PVA-co-PE nanofiber on both surfaces of the polypropylene substrate (denoted as PP) and then selectively decorating one side with hydrophobic fluorosilane. The obtained Janus PVA-co-PE membranes can effectively separate stabilized emulsions, including nonionic, cationic, and anionic types, and they display high separation efficiency (>99.9%) and promising flux solely driven by gravity. The synergistic effect between the bactericidal properties of Ag + and antiadhesion of superhydrophobicity endows the AgNPs@PVA-co-PE membrane with a strong antibacterial activity against Escherichia coli and Staphylococcus aureus.

Recent advances in superwetting materials for separation of oil/water mixtures

“…12b). 123 Other Janus membranes for on-demand separation include Janus SSM, 124 Janus AgNPs@PVA- co -PE (PVA, polyvinyl alcohol; PE, polyethylene), 125 Janus PDA/PET/PVDF (polydopamine/polyethylene terephthalate/polyvinylidene fluoride), 126 etc .…”

Large-Area Preparation of a Robust Superamphiphobic Coating for Chemical Mechanical Polishing Application

“…In recent years, superamphiphobic surfaces inspired by the lotus leaf in nature have attracted great attention because of their potential application in self-cleaning, − anti-icing, , drag reduction, , corrosion resistance, , flame retardant, , oil–water separation, − and other applications. It is known that low surface energy and surface microstructure are two prerequisites for the formation of superamphiphobic surfaces. , Various special shapes that mimic organisms and plants in nature have been prepared to obtain superamphiphobic surfaces, − but most of the hierarchical structures have poor mechanical strength, not suitable for the long-term service of coatings. , Polydimethylsiloxane (PDMS) is commonly used for the preparation of superamphiphobic surfaces due to its inherent chemical robustness and low surface energy. , Additionally, PDMS is flexible and highly elastic, allowing it to resist mechanical damage through energy deformation .…”

Durable Polycationic Superhydrophilic Membrane toward Excellent Antibacterial Performance and Oil–Water Separation

“…33,34 The bacteria lingering on the membrane will block the pores and decrease the separation ability of the membrane against the oil, leading to performance degradation. 35,36 More importantly, the membrane will be damaged and discarded once it fails to perform its duties under mechanical attack. The discarded PVDF membrane is hard to degrade, causing a series of durable environmental and ecological problems.…”

“…A hydration layer could be formed preferentially on the hydrophilic PVDF membrane surface before oil and water separation, − which prevents the surface from being contaminated by the oil . However, the fouling coming from the bacteria in water is inevitable. , The bacteria lingering on the membrane will block the pores and decrease the separation ability of the membrane against the oil, leading to performance degradation. , More importantly, the membrane will be damaged and discarded once it fails to perform its duties under mechanical attack. The discarded PVDF membrane is hard to degrade, causing a series of durable environmental and ecological problems.…”