Superhydrophobic PET@ZnO Nanofibrous Membrane Extract from Waste Plastic for Efficient Water-In-Oil Emulsion Separation

Waste plastics and oil pollution from industry and daily life have posed a serious threat to the environment, and it is the general trend to resource recycle them. Herein, this work presents a sustainable and environmentally friendly strategy for fabricating the superhydrophobic polyethylene terephthalate@ZnO nanofibrous membrane (PET@ZnO membrane) using Coca-Cola plastic bottles as raw materials, as well as its application in oil–water separation. In this strategy, the PET membranes were fabricated by combining the dual-solvent dissolution treatment and electrospinning processes. Then, the superhydrophobic PET@ZnO membrane with hierarchical architectures was fabricated by in situ growth of hierarchical ZnO nanopillars on the PET fiber surfaces, followed by hydrophobic modification. The obtained superhydrophobic PET@ZnO membrane shows an interconnected structure and superhydrophobic properties with a static water contact angle of 153 ± 2°. Moreover, the superhydrophobic PET@ZnO membrane has excellent repellence toward a corrosive solution, implying excellent chemical stability. The separation efficiency of various water-in-oil emulsions was higher than 99.6%, solely employing the gravity-driven process. Most importantly, there is no significant effect on the separation properties and still maintains a remarkable separation efficiency of almost 99.7%, while the separation flux was retained above 992 L m–2 h–1 after using the same membrane for 10 subsequent cycles. Therefore, this work not only provides a high-value-added strategy for resource recycling of waste plastic and oil but also gives an excellent membrane material with stable chemical properties for applications in wastewater treatment and chemical separation.