Catalytic degradation of 4-chlorophenol by persulfate activated with magnetic CuFe2O4-Fe3O4 composite

A novel heterogeneous CuFe2O4-Fe3O4 composite prepared in one pot was applied to activate persulfate for the degradation of 4-chlorophenol. The properties of CuFe2O4-Fe3O4 composite were characterized by the specific area (S-BET) measurement, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier-transform infrared spectra (FTIR). The experimental results showed that the catalytic performance of CuFe2O4-Fe3O4 is better than those of CuFe2O4 alone, Fe3O4 alone and the mixture (CuFe2O4/Fe3O4). The catalytic properties were investigated under different conditions (initial pH value, catalyst load, Na2S2O8 dosage and 4-chlorophenol concentration). It was found that the removal of the 100 mg/L 4-chlorophenol achieved 96.35% after 120 min treatment with 2 g/L Na(2)S(2)O(8 )when the initial pH value was 11. Under the same condition, total organic carbon (TOC) removal of 4-chlorophenol was 93.4% which demonstrated the degradation led to higher mineralization. Furthermore, the catalytic degradation mechanism was discussed. Cu(II), Fe(II) activated Na2S2O8 to form SO4 center dot- and (OH)-O-center dot which was demonstrated by X-ray photo-electron spectroscopy (XPS) analysis and the quenching experiments.