Removal of polyethylene terephthalate plastics waste via Co–CeO2 photocatalyst–activated peroxymonosulfate strategy

Polyethylene terephthalate (PET) plastic, widely used for packaging owing to its excellent properties, has become a major contributor to plastic waste, for which satisfactory recycling and upgrading treatment technologies are lacking. In this study, Co-doped CeO2 was used as a photocatalyst to degrade PET plastics in water, and PET degradation was measured according to the weight loss rate. Peroxymonosulfate (PMS) addition to the photocatalytic system enabled the degradation of 53.82 ± 4.48 % of PET plastics, highlighting the excellent PET plastic degradation capability of the photocatalytic PMS system. The study investigated the effects of the catalyst-to-plastic ratio, PMS concentration, initial pH, inorganic anions, humic acid concentration, and hydrogen peroxide (H2O2) addition on the catalytic oxidation system. Contrast experiments revealed that H2O2 addition to the photocatalysis/PMS oxidation system further improved the PET plastic degradation efficiency (91.61 ± 1.50 %). Liquid product analysis, electron paramagnetic resonance, and free radical quenching experiments confirmed that SO4− played the most significant role in PET degradation. Finally, a possible mechanism for the degradation of PET plastics in water using the photocatalysis/PMS oxidation system was proposed.