Enhanced photocatalytic degradation of diazinon using Ni:ZnO/Fe₃O₄ nanocomposite under solar light

Background: The increasing photocatalytic activity of Ni:ZnO/Fe₃O₄ nanocomposite in the diazinon degradation under solar light compared to bare ZnO and Ni:ZnO nanoparticles was examined. Methods: The synthesized nanoparticles and nanocomposite were characterized by SEM, MAP-EDX, XRD, FTIR, DLS, Zeta Potential and UV–Vis Spectrophotometer methods. The photocatalytic degradation of diazinon was investigated under sunlight illumination while continuously mixing on a stirrer for 180 min. Significant findings: The highest degradation efficiency was achieved for 1.5 wt% Ni:ZnO nanoparticles and 1.0 wt% Ni:ZnO/Fe₃O₄ nanocomposite at a diazinon concentration of 10 mg/L for the nanoparticle dose equal to 2 g/L was 95 % and 93 %, respectively. The recycling photocatalysts were investigated. Application of H₂O₂, potassium peroxymonosulfate (PMS) and S₂O₈²⁻ as chemical oxidants increased the photocatalytic activity of the nanocomposite. The use of 1.0 wt% Ni:ZnO/Fe₃O₄ nanocomposite along with 0.01 M H₂O₂ displayed the increasing photocatalytic performance. The simultaneous photocatalytic degradation efficiency of combined H₂O₂ and 1.0 wt% NZF nanocomposite for 100 mg/l of diazinon increased from 44 to 82 %. The photocatalytic mechanism of diazinon was proposed in three pathways.