Fabrication of poly(ethylene terephthalate)-based porous sponges for oil-water separation

The accumulation of plastic waste poses a long-term threat to the environment, while oil pollution causes immediate and serious damage. In this study, we proposed a method to repurpose poly(ethylene terephthalate) (PET), one of the most abundant plastics, into an oil sorbent . By mixing and crosslinking with polyethylene glycol (PEG) using hexamethylene diisocyanate trimer (HDIT), the PET can be reformed as a porous sponge with high porosity and moderate mechanical strength. The sponge can absorb floating oil from water with a capacity of up to 22 g/g, demulsify O/W emulsions of different oil contents (1–4 %) with efficiencies of over 97 %, and have a high flux (∼726.7 L·m −2 ·h −1 ) under gravity. The sponge prepared with recycled PET materials shows identical mechanical properties and oil-water separation efficiencies. This work demonstrates a sustainable and promising approach to simultaneously managing plastic waste and addressing various oil pollutions, aligning also with the principles of a circular economy.