The removal of tetracycline and metronidazole from water using zinc ferrite nanomaterials

The growing prevalence of antibiotic contaminants in aquatic environments poses significant risks to human health and the ecosystem, necessitating the development of advanced remediation strategies. This study reports the synthesis of pure spinel-phase zinc ferrite (ZnFe2O4) nanoparticles via co-precipitation and evaluates their adsorptive performance for removing tetracycline (TC) and metronidazole (MNZ) from water. The nanomaterials characterisation was conducted using X-ray diffraction, SEM, TEM, and FTIR techniques, which validated the formation of nanoscale zinc ferrite with a pHpzc of 7.2, favouring pH-dependent adsorption. Batch adsorption experiments revealed that ZnFe2O4 exhibits high removal efficiency for TC as compared to MNZ, with optimal performance at near-neutral pH, higher adsorbent dosages, and lower initial contaminant concentrations. Kinetic investigations follows pseudo-second-order model, indicating that chemisorption is the prevailing mechanism. The Langmuir isotherm model showed the best fitwith high correlation factors (R2) of 0.999, indicating monolayer adsorption on a homogenous surface in both cases. The maximum adsorption capacities (qm) for TC and MNZ were found to be 13.83 and 14.68 respectively. These results highlight the potential of ZnFe2O4 nanoparticles as a robust, reusable, and magnetically separable adsorbent for the efficient removal of multi-class antibiotics, offering a promising solution for sustainable water purification and contributing to the achievement of Sustanable Development Goal 6.