Heterogeneous catalytic degradation of phenol by a Fenton-type reaction using copper ferrites (CuFe2O4)

The potential application of copper ferrite (CuFe2O4) as a heterogeneous catalyst in the process of phenol degradation was investigated using high performance liquid chromatography (HPLC). CuFe2O4 nanoparticles were synthesized by sol-gel auto combustion and co-precipitation methods, and subsequently were calcined at 500 degrees C and 750 degrees C. The prepared ferrites were characterized for their morphology, crystallinity, purity, and stability using various techniques such as X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and BET surface area analysis. The sol-gel derived CuFe2O4 particles exhibited spinel phases of higher porosity and crystallinity as well as higher catalytic activity toward the degradation of phenol. Calcination of CuFe2O4 resulted in larger particles of higher purity and crystallinity, but of lower catalytic activity towards the degradation of phenol. The catalytic activity of the sol-gel CuFe2O4 was compared with the activity of two other sol-gel prepared ferrite catalysts, zinc ferrite (ZnFe2O4) and magnesium ferrite (MgFe2O4) catalysts, and with a commercial titanium dioxide (TiO2) catalyst. Among these catalysts, HPLC results demonstrated that CuFe2O4 exhibited the highest catalytic activity towards the degradation of phenol. Furthermore, the effects of several experimental parameters on the degradation rate of phenol over CuFe2O4 were investigated including the solution pH, reaction temperature, H2O2 concentration, catalyst loading, H2O2 addition mode, stirring, and the presence of UV or sunlight radiations. The degradation rate was enhanced by increasing the H2O2 concentrations, the CuFe2O4 catalyst loadings, or the reaction temperature. A faster and complete removal of phenol was observed under acidic conditions or under the presence of UV or sunlight radiation. CuFe2O4 was successfully regenerated and reused for five degradation cycles without noticeable loss in its activity.