Valorization of Polyethylene Terephthalate (PET) Plastic Wastes as Nanofibrous Membranes for Oil Removal: Sustainable Solution for Plastic Waste and Oil Pollution

The accumulation of plastic wastes has become a global environmental issue, because of their ever-growing production, slow degradation, and potential environmental hazards. Consequently, reducing their presence in the environment by upcycling has sparked tremendous research interest. Herein, we report the valorization of poly(ethylene terephthalate) (PET) plastic wastes to produce nanofibrous adsorptive membranes for their applications in oil removal. In this study, plastic wastes derived from PET bottles were dissolved in trifluoroacetic acid (TFA) or a TFA/dichloromethane (DCM) binary solvent system and then electrospun into nanofibrous recycled PET (rPET) membranes. The nanofiber morphology was tuned by adjusting the polymer concentration. The nanofibers produced via electrospinning from TFA solutions were more uniform than those produced using TFA/DCM. The influence of acid-mediated recycling on the PET structure was explored via thermogravimetric and X-ray photoelectron spectroscopy analyses. A dynamic mechanical analysis showed that the membranes exhibited high flexibility with effective Young's moduli. The sorption capacities of the nanofibrous PET membranes for crude oil, diesel, gasoline, and pump oil were 22.9 ± 2, 19.6 ± 1.8, 11.1 ± 1, and 19.3 ± 1.6 g g-1, respectively. The membrane could be recycled by squeezing and reused five times for oil removal while maintaining an sorption capacity of >75%. After the sorption tests, an apparent increase in the fiber diameter was observed due to the oil uptake into the fiber matrix. The present study provides a sustainable solution to plastic and oil pollution management, minimizing the production of new carbon-based materials and lowering carbon emissions. This work aligns with the United Nations' Sustainable Development Goals, specifically, Goal #12 on responsible consumption and production and #14 on life below water.