Microwave responsive copper-ferrite (CuFe2O4 ) encapsulated in molybdenum-disulfide (MoS2 ) nanoflower catalyst for antibiotic removal via persulfate oxidation

Microwave (MW) responsive copper-ferrite/molybdenum-disulfide (CuFe2O4/MoS2 ) nanoflower catalyst was implemented for rapid antibiotic metronidazole (MNZ) degradation via persulfate oxidation under MW irradiation. The catalyst was synthesized via co -precipitation followed by hydrothermal methods, and characterized by XRD, FTIR, SEM, TEM, VSM, XPS, and UV -DRS. As a first step, MW induced MNZ removal was studied at different initial mass of CuFe2O4 /MoS2 (2.5 -20%), where 5% CuFe2O4 in the nanocomposite performed the best. Within 5 min of MW irradiation, 100% MNZ removal was observed (K-obs - 1.063 min(-1) ) under the optimal reaction conditions (i.e., CuFe2O4 /MoS2 dose - 0.4 g/L; PS dose - 100 mg/L; temperature - 90 C-degrees; and MW power - 350 W). The MNZ removal was independent of solution pH 3 -11, and the removal was by SO4 center dot- and (OH)-O-center dot radicals alongside the limited contribution from O-2(center dot-) . PS and H2O were thermally decomposed to produce SO4 center dot- and center dot OH radicals, whereas intrinsic semiconductor CFO/MS with a narrow bandgap of 1.53 eV allowed electrons to jump into conduction band from valance band to create SO4 center dot- and O-2(center dot-) . However, the performance of MW system was inhibited by the presence of anions in the order of Cl-< NO3-1200 C-degrees) for MNZ removal. Synergistically, redox couples of transitional metals contributed to MNZ degradation.