Work

Green synthesis and sunlight-driven photocatalytic degradation of diclofenac using biogenic Co₃O₄ nanoparticles derived from Carica papaya peel waste

Year: 2026

Type: article

Abstract: The increasing presence of pharmaceutical contaminants such as diclofenac in aquatic environments poses serious ecological and health risks, necessitating efficient and sustainable degradation approaches. In this study, Co₃O₄ nanoparticles were green-synthesized using Carica papaya peel waste extract as a natural reducing and stabilizing agent and calcinated at temperatures ranging from 300 to 900 °C . XRD analysis confirmed the formation of a highly crystalline cubic spinel Co₃O₄ phase, while FESEM images showed quasi-spherical, porous nanoparticles with sizes of 50–70 nm. Elemental analysis revealed dominant cobalt (65.26 wt%) and oxygen (28.52 wt%), consistent with Co₃O₄ stoichiometry, with only trace amounts of phosphorus and magnesium originating from intrinsic phytochemical constituents. FTIR verified Co–O vibrations and removal of organic residues, and UV-Vis/DRS analyses showed strong visible-light absorption with a tunable band gap (1.69–1.49 eV). The photocatalytic degradation of diclofenac under natural sunlight achieved 93 % efficiency at pH 2 within 270 min for the 900 °C sample (1 mg/mL dosage), following pseudo-first-order kinetics. These results demonstrate that biogenic Co₃O₄ nanoparticles serve as efficient, cost-effective, and sustainable photocatalysts for solar-assisted degradation of pharmaceutical pollutants in wastewater.

Source: Next Materials

DOI: 10.1016/j.nxmate.2026.101712