To develop an easy-to-prepare magnetic carbon-supported cobalt (MCC) catalyst, hexacyanocobaltate salt, as the first time, was employed as a precursor to prepare MCC via a simple one-step carbonization. The magnetism, porosity and carbon-supported cobalt of MCC allow it to be a promising catalyst to activate Oxone for generation of sulfate radicals which can degrade toxic Amaranth dye. Parameters influencing the Amaranth degradation were examined including catalyst loading, Oxone dosage, temperature, pH, co-existing compounds as well as inhibitors. While increases in MCC loading and Oxone dosage both enhanced the degradation extent and kinetics, the Amaranth degradation was more sensitive to the variation of Oxone dosage. The degradation was also preferable at elevated temperature and low pH. In addition, the Amaranth degradation by MCC-activated Oxone remained quite stable in the presence of salts and anionic surfactant. Through the effect of various inhibitors and ESR spectroscopic analysis, the Amaranth degradation primarily involved sulfate radicals. MCC also exhibited a consistent catalytic activity over multiple degradation cycles and stable chemical composition. Considering the magnetically controllability of MCC together with the aforementioned features, MCC can be a promising heterogeneous catalyst to activate Oxone for degradation of toxic contaminants. (C) 2016 Elsevier B.V. All rights reserved.