In this study, a sludge-derived biochar (SBC) was prepared, characterized and applied to activate peroxymonosulfate (PMS) for the degradation of triclosan (TCS) in water and wastewater. The results showed that SBC had porous structure with specific surface area of 157.4 m(2) g(-1). The optimal conditions for TCS degradation were examined as follows: pH 7.2, biochar dosage of 1.0 g/L and PMS concentration of 0.8 mM at 25 degrees C. The removal efficiency of total organic carbon (TOC) reached 32.5% within 240 min under optimal conditions. Hydroxyl radicals, sulfate radicals and singlet oxygen contributed to TCS degradation. Dechlorination and hydroxylation were the main pathway of TCS degradation. Based on the intermediate products detected during the TCS degradation, the degradation pathway of TCS was tentatively proposed. This study demonstrated that SBC could be an effective activator of PMS for the degradation of toxic organic pollutants in water and wastewater.