Selective mineralization of phenolic pollutants via non-radical pathways: A photochemical direct charge transfer mechanism based on peryleneimide (PDI)

Conventional free radical advanced oxidation processes are prone to inefficient mineralization and generation of toxic by-products due to the depletion of free radicals by non-target pollutants, and thus it is crucial to remove difficult-to-degrade organic pollutants efficiently and selectively in complex water bodies. Herein, we constructed a photochemical direct charge transfer elective oxidation/mineralization system based on peryleneimide supramolecular photocatalysts and variable-valent metal ions (PDI/M n+x ) to selectively oxidize and mineralize phenolic organic pollutants, achieving an 8–13-fold increase in the mineralization rate. Experimental and theoretical calculations elucidated the possible selectivity mechanism: the oxidation potentials of active species (photogenerated charge) and phenolic organic pollutants (PCs) in the system govern the oxidation kinetics and mineralization efficiency, and a typical negative correlation exists. Additionally, by leveraging the dyeing properties of PDI photocatalysts to load them onto white nonwoven fabrics, efficient degradation of organic pollutants in water under natural light conditions can be achieved. The system exhibits a mineralization capacity 2.3–4.7 times higher than that of the homogeneous Fenton system, along with lower treatment costs and comparable removal rates. This study provides a cost-effective solution for the purification of difficult-to-degrade organic pollutants in complex water bodies through non-radical pathways.