In this study, the photodegradation rate of metronidazole aqueous solution was investigated by NiFe2O4 and ZnFe2O4 photocatalysts synthesized by co-precipitation method individually and in the heterostructure, with the magnetic feature confirmed by VSM analysis. XRD, FTIR, SEM-EDX, X-ray mapping, and DRS were also used to characterize the samples. After proving the synergistic effects of the ZnNiFe2O4 heterojunction system via a p-n junction mechanism concerning the individual ZnFe2O4 and NiFe2O4 system, the photodegradation experiments showed its best photocatalytic activity when its ZnFe2O4: NiFe2O4 molar ratio is 3:1. Thus, this catalyst was used to study of the effects of NaCl, NaHCO3, Na2SO4 and ascorbic acid as scavenging agents kinetically on the MZ photodegradation. NaCl’s critical decrease in photodegradation efficiency confirmed the significant role of hydroxyl radicals in MZ photodegradation. For the kinetics of MZ photodegradation and mineralization, the rate constants were obtained 0.0522 min-1 (t1/2 = 13.27 min) and 0.0501 min-1 (t1/2 = 13.58 min), respectively, applying the Hinshelwood model. In the kinetics study of the temperature effects, obtained parameters with the Arrhenius equation are the frequency factor (1.015 × 104 min-1) and the activation energy (17.65 kJ mol-1). Thermodynamic parameters for the degradation of MZ molecules calculated; ΔSo (- 0.243 kJ mol-1). A charge carriers transfer mechanism was proposed based on the scavenging agents results and the VB and CB potential positions. The application of the synthesized catalyst has been tried in different matrices and for the degradation of other drugs. The stability of this catalyst has been investigated and confirmed statistically.
