Acceleration of peroxymonosulfate decomposition by a magnetic MoS2/CuFe2O4 heterogeneous catalyst for rapid degradation of fluoxetine

Abstract By modifying copper ferrite on the surface of molybdenum disulfide (MoS2/CuFe2O4), an excellent catalyst that can be used for interaction with peroxymonosulfate was successfully synthesized. Owing to the large number of active sites (unsaturated sulfur) on the surface of the composite material, the electron transfer and decomposition rate of the oxidant in the reaction system were significantly enhanced. The removal ability was the strongest when the molar ratio of MoS2/CuFe2O4 was 1.5. The removal efficiency of fluoxetine reached 97.7% within 20 min, which was higher than those obtained by pure MoS2 (38.6%) and CuFe2O4 (22.1%). The free radical test and electron paramagnetic resonance analysis indicated that sulfate radicals and hydroxyl radicals were the dominant reactive oxygen species in the reaction system. In addition, in situ Raman spectroscopy revealed that peroxymonosulfate was rapidly decomposed in the composite material system. Meanwhile, the degradation products of fluoxetine were explored by high-performance liquid chromatography-tandem mass spectrometry, and a transformation pathway based on nine intermediates was proposed, mainly involving the breaking of the carbon-oxygen bond around oxygen atom, hydroxylation, and ring-opening reactions of fluoxetine and its intermediates.