In this work, the novel multivalent Mn3O4-MnO2 composite catalyst was synthesized and employed for peroxymonosulfate (PMS) activation to realize ciprofloxacin (CIP) degradation. Results showed that 97.6% of CIP (50 mu M) was removed in PMS/Mn3O4-MnO2 system by adsorption and further degradation within 25 min at the dosage of 1 mM PMS and 0.1 g/L Mn3O4-MnO2. The CIP degradation followed the pseudo-first-order kinetic model and the highest kinetic constant of 0.139 min(-1) was achieved. Moreover, the effects of solution pH, coexisting anions and natural organic matter on CIP removal were investigated. The optimum pH in PMS/Mn3O4-MnO2 system for CIP removal was neutral. The coexisting anions such as HCO3, NO3 and SO42 inhibited the degradation process while Cl enhanced the process. The natural organic matter (NOM) presented positive effect on CIP degradation at 1.0 mg/L and detrimental effect at 3.0 and 5.0 mg/L. Furthermore, the mechanism of PMS activation by Mn3O4-MnO2 was interpreted. The PMS was highly activated to sulfate and hydroxide radicals by the redox pairs of Mn(III)/Mn(II) and Mn (IV)/Mn(III) in Mn3O4-MnO2 composite. Accordingly, the transformation products of CIP were determined and the degradation pathways in PMS/Mn3O4-MnO2 system were proposed. These findings would make a significant contribution towards removing antibiotics from water through PMS oxidation system. (C) 2017 Elsevier B.V. All rights reserved.