BACKGROUND: The presence of sulfonamide antibiotics in aquatic environments has received increasing attention. In this study, the nanocomposite Fe3O4-Mn3O4 was synthesized, characterized and used as a catalyst for the degradation of sulfamethazine (SMT) in a heterogeneous Fenton-like process. RESULTS: The composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), BET specific surface area, vibrating sample spectrometry (VSM), Raman and Fourier transform infrared (FTIR) spectroscopy before and after use. The catalytic activity was evaluated under different conditions, including pH value, H2O2 dosage, catalyst dosage, temperature and initial concentration of SMT. The removal efficiency of SMT was more than 99% in 50 min at pH=3, T=45 degrees C, H2O2=6 mmol L-1, Fe3O4-Mn3O4 dosage=0.5 g L-1, SMT=20mgL(-1). CONCLUSIONS: Fe3O4-Mn3O4 composite was an efficient catalyst for degradation of SMT in a Fenton-like process. (C) 2016 Society of Chemical Industry