Abstract
Iron oxide nanocomposites (Fe(3)O(4)@BC-1, Fe(3)O(4)@BC-2, and Fe(3)O(4)@BC-3) were synthesized via an ultrasound-assisted method at 5, 10, and 15 min to investigate their morphological, optical, and photocatalytic properties. Powder X-ray diffraction (P-XRD) analysis confirmed the formation of Fe(3)O(4) with a cubic spinel structure. TEM analysis revealed that Fe(3)O(4)@BC-1 exhibited irregular rod- and plate-like structures with a particle size of 6.4 nm, Fe(3)O(4)@BC-2 displayed square-shaped particles with a mean size of 8.3 nm, and Fe(3)O(4)@BC-3 consisted of agglomerated particles with a size of 9.8 nm. Optical analysis showed a redshift in absorption peaks from 400 nm (2.36 eV) for Fe(3)O(4)@BC-1 to 417 nm (2.28 eV) for Fe(3)O(4)@BC-2, and 418 nm (2.32 eV) for Fe(3)O(4)@BC-3. The nanocomposites were evaluated as photocatalysts against Congo red (CR) and crystal violet (CV) using response surface methodology. Fe(3)O(4)@BC-3 exhibited the highest photocatalytic degradation efficiency of 99.86% of CR under optimal conditions (120 min, 3 mg, 15 ppm, pH 3) and Fe(3)O(4)@BC-2 achieved 99.28% degradation of CV under 90 min, 8 mg, and pH 8 for 5 ppm CV. Reactive species analysis confirmed hydroxyl (˙OH) and superoxide radicals (˙O(2) (-)) as the dominant contributors to the dye's degradation.