Preparation of separable MnFe2O4/ZnO/CQDs as a visible light photocatalyst for Gentamicin treatment

In the present study, we report a method for the preparation of magnetically separable, visible-light activated ZnO photocatalyst for wastewater treatment from pharmaceutical drugs. The photocatalyst consists of Manganese Ferrite core, coated with Zinc Oxide, doped with N,S-Carbon Quantum Dots. The photocatalyst was characterized by XRD, HR-TEM, FT-IR, VSM, BET adsorption, UV–Vis absorption, and Photoluminescence. FT-IR confirmed the presence of distinct bonds characteristics of the different components. VSM showed decrease in magnetization of MnFe₂O₄ in the composite but can still be attracted to a magnet. BET results showed the surface area of photocatalyst is 22.56 m² g⁻¹, and pore diameter is 3.1 nm. Interestingly, the absorption of Zinc Oxide was shifted from UV range toward visible range. A decrease of PL spectrum was observed due to the suppression of defects emission. Electrochemical tests revealed reduced charge transfer resistance of the composite compared to pristine ZnO. The photocatalytic activity was evaluated by degrading Gentamicin antibiotic. Experimental data showed that Gentamicin degradation reached 69.1% during 2 h of