Transforming waste polyethylene terephthalate (PET) into high-performance activated carbon-supported composites for pollutant degradation: A synergy of experiments and DFT insights

To date, the global demand for clean water and environmentally detrimental human activities are among the most significant challenges humans face. Therefore, an urgent need is to innovate and implement more effective, sustainable solutions to protect the environment and preserve our vital water resources. In particular, this study successfully developed a new and suitable nanocomposite catalyst from waste polyethylene terephthalate (PET) plastics-derived activated carbon (P-AC) and applied it for the enhanced photo-degradation of tetracycline (TCHCl). Based on the characterizations and density functional theory (DFT) calculations, we suggest that the synergistic effect of adsorption and photocatalysis by synthesizing oxygen vacancy-rich Bi4O5Br2 (BOB) and Co3(PO4)2 (COP) immobilized on P-AC play a critical role in enhancing effectively further the degradation efficiency. Interestingly, the proposed S-scheme charge transfer mechanism demonstrated an impressive TC-HCl degradation efficiency of 90.7 % within 90 min under light irradiation. It notes that the degradation mechanism involved the pre-adsorption of TC-HCl onto the surface of functional group-rich activated carbon, which assisted in hastening the attack of O2 center dot- and h+. Nine primary intermediates were identified, framing three degradation pathways for TC-HCl as per liquid chromatography - mass spectrometry (LC-MS). Lastly, results of consecutive quadruplicate degradation experiments advocated the stability and reusability of the nanocomposite, highlighting the potential of upcycling plastic waste into valuable photocatalytic materials support, offering an effective and environmentally friendly solution for removing priority pollutants from water.