Utilization of plastic bottle waste of polyethylene terephthalate as a low-cost membrane and its modifications for gas separation.

Abstract

Polyethylene terephthalate (PET) is a widely used polymer in packaging products, leading to the daily disposal of millions of PET bottles as waste. 1.1 to 8.8 million tonnes of plastic waste enter the sea each year. The environmental challenge of non-biodegradable PET waste can be addressed by utilizing it as a thin-layer membrane for gas separation. This study modified the PET membrane by blending it with Pebax polymer and adding zeolite as a filler to enhance its performance. Characterization techniques, including FTIR, SEM, TGA, tensile strength testing, and contact angle measurements, were performed on all modified membranes. The membranes were prepared using phase inversion via immersion precipitation. The results showed that the PET waste membrane had a denser surface pore morphology and asymmetrical cross-sectional pores than other membranes. Adding Pebax and zeolite resulted in a more regular sponge-like pore structure. The PET, PET-Pebax, and PET-Zeolite NaY-Pebax membranes exhibited hydrophilic properties, as indicated by contact angle values ranging from 48-78°. Regarding CO2/CH4 separation, the 9% PET-Pebax membrane had the highest CO2 permeability, a 21% increase from the original PET waste membrane. Adding zeolite to the 9% PET-Pebax membrane increased CO2 permeability to 1044%.