Dual-functional CdO/Fe₂O₃ nanocomposites synthesized via ultrasonication: A route to visible-light photocatalysis and antibacterial action

Industrial effluents with persistent dyes and pathogens challenge water quality, necessitating innovative treatment methods that integrate photocatalytic and antimicrobial functions. In this study, CdO/Fe₂O₃ nanocomposites were synthesized via a co-precipitation process and calcined at 500°C to enhance crystallinity. PXRD analysis revealed a crystalline grain size of 21.40 nm, while FE-SEM showed particle sizes between 20 to 40 nm. EDAX confirmed uniform elemental distribution, with an average particle diameter of about 65.3 nm. FT-IR and Raman spectroscopy identified strong metal-oxide bonds at 400 to 850 cm⁻¹. Optical studies indicated a reduced bandgap of 2.4 eV, improving visible light absorption. Photoluminescence analysis showed decreased electron-hole recombination due to oxygen vacancies. Photocatalytic tests achieved degradation efficiencies of MO (88%) and CR (90%) under visible light irradiation of 60 minutes, with Congo red degrading more rapidly. k values of 1.76 × 10 -3 min -1 for CR and 1.17 × 10 -3 min -1 for MO suggest that the degradation process proceeds in a prominent way. Antibacterial assessment against Gram-positive ( Staphylococcus aureus, Bacillus sp .) and Gram-negative ( Escherichia coli, Pseudomonas aeruginosa ) strains showed a zone of inhibition increasing from 14 mm (25 µL) to 21 mm (100 µL), compared to the positive control (27 mm), with 78% activity at 100 µL. 1 mg of the prepared material was dissolved in 10 mL of ethanol, which served as the stock solution. The required concentrations of 25 μL, 50 μL, 75 μL, and 100 μL were then prepared from this stock solution. This nanocomposite paves the way for enhancing the dual functionality of CdO/Fe₂O₃ nanocomposites, enabling effective wastewater treatment that targets both chemical and microbiological contaminants.