Photocatalytic Degradation of Acetaminophen by g-C3N4/CQD/Ag Nanocomposites from Aqueous Media

Ternary g-C3N4/CQD/Ag photocatalysts were synthesized via deposition of carbon quantum dots (CQDs) and silver nanoparticles (Ag) onto graphitic carbon nitride (g-C3N4) for efficient acetaminophen degradation. The nanocomposites exhibited enhanced photoresponse and broad-spectrum photocatalytic activity under both UV (254 nm, 250 W) and Xenon (>420 nm, 500 W) irradiation. Characterization by XRD, FTIR, SEM, PL, and EDX elucidated the material’s composition, structure, morphology, and optical properties. Optimized photocatalytic degradation of acetaminophen (50 mg/L) was achieved at pH 7 with 0.6 g/L catalyst loading and 60 min irradiation, yielding degradation efficiencies of 87.5% (UV) and 85.3% (Xenon). Radical quenching experiments and GC-MS analysis identified hydroxyl radicals as the primary reactive species and revealed a gradual decrease in intermediate toxicity during mineralization. This study demonstrates the superior photocatalytic performance of the ternary g-C3N4/CQD/Ag nanocomposites compared to binary systems for effective acetaminophen removal.