In this study, an environmentally friendly and economically viable bamboo biochar (BB) was modified by Fe3O4 and was applied for the treatment of real river sediments containing the endocrine disruptor chemical (EDC) 4-nonylphenol (4-NP). The microporosity of Fe3O4-BB was clearly observed from the N-2 adsorption isotherms. The catalytic performance of Fe3O4-BB is highly dependent on pH and the catalyst dosage. The degradation efficiency of 4-NP (85%) was achieved at pH 3.0 using an initial dosage of 3.33 g L-1 Fe3O4-BB and 2.3 x 10(-5) M persulfate (PS) in a biochar-sediment system. The kinetic behavior of 4-NP degradation with catalysis can be accounted by using the Langmuir-Hinshelwood type kinetic model. The MTT assay results indicated that Fe3O4-BB has a low potent cytotoxic effect and is therefore suitable for application in remediation of contaminated sediment.