Enhanced heterogeneous Fenton-like degradation of methylene blue by reduced CuFe 2 O 4 .

To facilitate rapid dye removal in oxidation processes, copper ferrite (CuFe 2 O 4 ) was isothermally reduced in a H 2 flow and used as a magnetically separable catalyst for activation of hydrogen peroxide (H 2 O 2 ). The physicochemical properties of the reduced CuFe 2 O 4 were characterized with several techniques, including transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and magnetometry. In the catalytic experiments, reduced CuFe 2 O 4 showed superior catalytic activity compared to raw CuFe 2 O 4 for the removal of methylene blue (MB) due to its relatively high surface area and loading Fe 0 /Cu 0 bimetallic particles. A limited amount of metal ions leached from the reduced CuFe 2 O 4 and these leached ions could act as homogeneous Fenton catalysts in MB degradation. The effects of experimental parameters such as pH, catalyst dosage and H 2 O 2 concentration were investigated. Free radical inhibition experiments and electron spin resonance (ESR) spectroscopy revealed that the main reactive species was hydroxyl radical (˙OH). Moreover, reduced CuFe 2 O 4 could be easily separated by using an external magnet after the reaction and remained good activity after being recycled five times, demonstrating its promising long-term application in the treatment of dye wastewater.