Synthesis, Characterization, and Kinetic Insights of MnZnFe₂O₄/SrWO₄ Ferrite–Tungstate Nanocomposite for Rapid Photocatalytic Degradation of Imidacloprid

Imidacloprid (IMI), the commonly used neonicotinoid pesticide, has emerged as a persistent aquatic contaminant due to its high solubility and stability, posing risks to non-target organisms and ecosystem health. In this study, a MnZnFe₂O₄/SrWO₄ ferrite–tungstate nanocomposite was synthesized via a hydrothermal process and its ability to photocatalytically degrade IMI under UV light was assessed. SEM, XRD and FT-IR were used to characterize the composite to confirm its structural and morphological features. Photocatalytic performance was systematically investigated by examining the effects of operational factors, including initial pollutant concentration, catalyst dosage, pH, and irradiation time. The MnZnFe₂O₄/SrWO₄ nanocomposite exhibited significantly enhanced activity, achieving up to 87% degradation of IMI within 30 minutes at pH 9, outperforming individual components (SrWO₄: 37%; MnZnFe₂O₄: 75%) under identical conditions. The degradation kinetics followed a pseudo-first-order model consistent with the Langmuir–Hinshelwood mechanism. Effective interfacial charge transfer between the ferrite and tungstate phases, which promotes electron-hole recombination and increases the production of reactive species, is responsible for the enhanced performance. Furthermore, the composite demonstrated good stability and reusability across several cycles, indicating its practical applicability. Overall, the results demonstrate the potential of MnZnFe₂O₄/SrWO₄ nanocomposites as efficient and sustainable photocatalysts for removing imidacloprid and similar organic contaminants from aqueous systems.