Metal-organic framework modified hydrophilic polyvinylidene fluoride porous membrane for efficient degerming selective oil/water emulsion separation

Developing a new type of superhydrophilic/underwater superoleophobic oil/water separation membrane with high separation efficiency, high throughput and bacteria separation has essential theoretical and practical significance for treating oily and medical wastewater. This work modified commercial PVDF membranes by knife coating and cross-linking, and PVDF/PVA/LPB/MOF hybrid separation membranes are manufactured. Hydrophilic polyvinyl alcohol (PVA) endows the separation membrane with good hydrophilicity. Lauramidopropyl Betaine (LPB) enhances intermolecular hydrogen bonding and improves the mechanical properties of the membrane. A Metal-organic framework (MOF) with excellent biocompatibility, UiO-66-NH2, plays a vital role in the separation of bacteria. The results of the morphology and surface chemistry of characterization analysis show that the PVDF/PVA/LPB/MOF hybrid separation membrane exhibits excellent superhydrophilicity (with a contact angle of 2°) and high-water flux (15600 L/m2h) and high separation efficiency (99%), and the nature of filtering bacteria while separating oil. After modification, the separation efficiency increased from 30% to 99%, showing strong oil stain resistance. Our finding suggests that the new type of super-hydrophilic/underwater superoleophobic oil/water separation membrane has potential value in practical applications.