Waste to treasure: A superwetting fiber membrane from waste PET plastic for water-in-oil emulsion separation

Polyethylene terephthalate (PET) plastic membrane has attracted significant attention in chemical separation and pollution control due to its high mechanical properties and excellent chemical stability. However, designing inexpensive and efficient PET membrane materials for oil-water separation from waste PET plastics is still challenging but of great significance to environmental safety and resource protection. In this work, a superwetting PET fiber membrane with excellent structural stability and wetting selectivity was prepared from waste PET plastic, via electrostatic spinning, in-situ deposition and surface modification. The obtained superwetting PET fiber membrane exhibits the flourishing pore structure, wettability of superhydrophobic/super-oleophilic, and corrosion resistance (weak acid, strong base). Due to its stable porous structure and wettability properties, the membrane is capable of separating multi-type water-in-oil emulsion successfully, while with ideal separation flux (over 1100 L ·m−2·h−1), and separation efficiency (99.0–99.9%). Additionally, after the reusability tests with the least number of 40 cycles, the membrane shows favorable separation stability and excellent reusing performance, which possesses tremendous potential for efficient and continuous separation of water-in-oil emulsions. Therefore, the simple yet effective waste-to-resource strategy for waste PET plastic can not only reduce the environmental pollution caused by microplastics, but also develop an inexpensive and efficient membrane material for industrial emulsion separation.