GREEN SYNTHESIS OF ZnO AND COFe₂O₄ NANOMATERIALS AND EVALUATION OF THEIR PHOTOCATALYTIC PERFORMANCE IN DEGRADATION OF METHYLENE BLUE IN WATER

Abstract

ZnO and CoFe₂O₄ nanoparticles were successfully synthesized by green synthesis using lime juice extract at
the annealing temperature of 500°C. XRD analysis confirmed that the obtained materials exhibited single
phase crystalline structures, with crystallite sizes of 13.9 nm (ZnO) and 10.0 nm (CoFe₂O₄). SEM and EDX
analyses revealed spherical morphologies and elemental compositions consistent with their stoichiometric
formulas. UV-Vis DRS studies indicated that ZnO primarily absorbs ultraviolet light (<400 nm), while
CoFe₂O₄ exhibited significant visible-light absorption. Bandgap energies determined via Tauc plot method
were 3.11 eV (ZnO) and 2.12 eV (CoFe₂O₄). Photocatalytic degradation of methylene blue achieved
efficiencies of 64.2% (ZnO) and 85.3% (CoFe₂O₄) after 180 minutes of irradiation.