ABSTRACT Synthetic dyes discharged into natural waters pose chronic risks to ecosystems and human health due to their chemical persistence and bioactivity. To mitigate these impacts, a magnetic ternary nanocomposite NiFe 2 O 4 /ZnO/Co 3 O 4 was engineered via a solvothermal route. The influence of postannealing (300°C, 400°C, and 500°C) was systematically examined using comprehensive characterizations such as FTIR, UV–vis, SEM with EDS, XRD, and VSM. XRD confirmed the coexistence of cubic spinel phases (NiFe 2 O 4 & Co 3 O 4 ) with hexagonal wurtzite ZnO. With increasing annealing temperature, the mean crystallite diameter grew from ∼17.51 to 28.83 nm, indicating thermally driven grain coarsening and enhanced crystallinity. VSM revealed a slight rise in remnant magnetization and decreased coercivity, consistent with improved magnetic domain ordering. Under simulated sunlight, these synergistic attributes translated to efficient photocatalysis, with mixed dye (MO + MB) degradation increasing monotonically with annealing temperature and reaching ∼100% within 180 min. Improved crystallinity, band structure tuning, magnetic separability, and broad visible‐light absorption acted in concert to deliver the high performance of this photocatalyst, making it a promising solution for mitigating synthetic dye impacts in natural waters. The nanocomposite's efficiency and magnetic properties make it an attractive option for environmental remediation.
Iqbal et al. (Sun,) studied this question.