Synthetic Studies of Aluminum-Doped Zn_0.5Mn_0.5AlxFe_2−xO₄ Ferrite for Photocatalytic Degradation of Atrazine Under Visible Light

The objective of this study was to synthesize and evaluate aluminum-doped zinc-manganese ferrite (Zn_0.5Mn_0.5AlxFe_2−xO₄ (X = 0, 0.2)) nanoparticles as efficient visible-light-driven photocatalysts for atrazine degradation in water. The nanoparticles were synthesized via the sol–gel method and characterized using XRD, FTIR, SEM–EDX, BET, UV–Vis DRS, and electrical resistivity measurements. Aluminum doping decreased the bandgap from 2.4 to 2.0 eV and improved the adsorption properties by increasing the surface area and pore volume compared to undoped Zn_0.5Mn_0.5Fe₂O₄. Photodegradation experiments revealed that Zn_0.5Mn_0.5Al_0.2Fe_1.8O₄ achieved 95% atrazine removal in 150 min under visible-light irradiation, outperforming the 75.45% removal achieved by undoped Zn_0.5Mn_0.5Fe₂O₄. This enhanced performance was attributed to aluminum-induced structural modifications that facilitated charge-separation and radical generation. The degradation followed first-order kinetics and hydroxyl radicals were identified as the primary reactive species. The effects of operational parameters, including the solution pH, atrazine concentration, catalyst dosage, temperature, light intensity, and H₂O₂ addition, were systematically investigated. Zn_0.5Mn_0.5Al_0.2Fe_1.8O₄ demonstrated reusability over five consecutive cycles with a slight decrease in efficiency. These findings highlight the potential of aluminum-doped zinc-manganese ferrites as efficient visible-light photocatalysts for environmental remediation.