Insights into CQDs-doped perylene diimide photocatalysts for the degradation of naproxen

Abstract

Advanced efficacious catalytic technologies have the capacity to enhance the degradation of emerging anthropogenic contaminants. Herein, the supramolecular nanofibers, namely carbon quantum dots doped perylene diimide (PDI/CQDs), was prepared via a one-step acidification polymerization method. The results showed that the rate constants of naproxen (NPX) were of 3.50 times in contrast to pristine PDI. When the doping amount of CQDs on PDI was 2%, the half-life of NPX was only 0.66 min in the PDI/CQDs photocatalytic system. The main active substances in the photocatalytic degradation of NPX were h+, O2•−, 1O2, H2O2 and •OH. Degradation mainly occurred through four paths, including the decarboxylation reaction, classical Ipso-substitution reaction, electron-dominated reaction, and intramolecular dehydration reaction paths. The obvious inhibitory effects of HA, Cl−, NO2– and HCO3– was observed, where a lower pH value was beneficial for the degradation of NPX. An overall mechanism was proposed through Density Functional Theory calculations of high-efficiency electron-hole separation of PDI/CQDs. To improve the nanomaterial applicability, PDI/CQDs cellulose acetate membrane was synthesized and used under different water conditions, which further revealed the stability and efficient of this membrane. Ultimately, the aggregate results provided basic supportive data for the remediation of contaminants in water and wastewater.