Microwave-assisted preparation of ZnFe2O4@methyl cellulose as a new nano-biomagnetic photocatalyst for photodegradation of metronidazole.

In the present study, ZnFe2O4@methyl cellulose (MC) nano-biomagnetic photocatalyst was rapidly prepared based on a microwave-assisted method. FTIR, FESEM, EDS, UV-DRS, XRD, and VSM were performed to characterize the structure of as-prepared ZnFe2O4@MC. The removal efficiency of Metronidazole (MNZ) degradation was 92.65% and 71.12% in synthetic and real samples under optimal conditions, respectively. The removal efficiency of TOC was also reported to be 77.87% under optimal conditions. The kinetic linear models showed that the photocatalytic degradation of MNZ follows either a pseudo-first-order kinetic or the Langmuir-Hinshelwood model. The correlation coefficients (R2) were 0.92, 0.97, 0.99, and 0.94, respectively at 5, 10, 20, and 30 mg/L. The equilibrium adsorption coefficient (KL-H) of the Langmuir-Hinshelwood model and the superficial reaction rate constant (Kc) were 0.633 Lmg-1 and 0.203 mg/L min-1, respectively. The participation of active species such as holes and hydroxyl and superoxide radicals was studied during MNZ photodegradation with organic and inorganic radical scavengers. Finally, the nano-biomagnetic catalyst could be reused for six further runs without remarkable changes in catalytic efficiencies. In this study, we present a new magnetic nanocomposite and a novel strategy for antibiotic removal from aqueous media.