Ambivalent photocatalytic strategies for plastic waste conversion: Alkalinized carbon nitride for H2O2 production and complete mineralization

Plastic waste poses a significant environmental threat due to its widespread use and disposal, necessitating innovative upcycling methods. Here, we introduce alkalinized carbon nitride (Alk-CN) as an efficient photocatalyst for the solar-driven photoreforming of polyethylene terephthalate (PET) into hydrogen peroxide (H2O2) in alkaline environments. Alk-CN also demonstrates versatility for H2O2 production with other polyester-based plastics, including polybutylene terephthalate and polylactic acid. This study pioneers an innovative dual approach to managing PET waste: (i) photoreforming to produce H2O2 and recover TPA from bulk PET waste and (ii) utilizing an AOP system with in-situ generated H2O2 under UV irradiation for the complete mineralization of trace PET waste in wastewater. These findings offer viable strategies for transforming plastic waste into valuable products or achieving complete mineralization, leveraging solar-driven photocatalytic reactions for environmental remediation and resource recovery.