Degradation of acetaminophen using persulfate activated with P-doped biochar and thiosulfate

Abstract

• Acetaminophen was rapidly degraded in persulfate/P-doped biochar/thiosulfate system. • A synergistic effect existed among persulfate, p-doped biochar and thiosulfate. • Electron transfer could be responsible for the degradation of acetaminophen. • The system maintained high removal efficiency in the water from difference sources. In the study, p-doped biochar (PBC) was prepared by the pyrolysis of H 3 PO 4 -impregnated cyanobacteria and used together with thiosulfate (TS) to activate persulfate (PS) for the degradation of acetaminophen (ACP). The biochar was characterized and the results showed that H 3 PO 4 treatment had a pronounced effect on the surface structure and chemical composition of biochar. ACP (0.05 mmol/L) could be completely removed within 90 min under the optimal conditions: 2.0 mmo/L of PS, 0.1 g/L of PBC and 2.0 mmol/L of TS. A synergistic effect existed among PS, PBC and TS. The PS/PBC/TS system maintained high removal efficiency for ACP in the water from difference sources and Cl - (< 2.0 mmol/L) had little effect on it. Quenching experiments, electron paramagnetic resonance measurements and ion analysis revealed that free radicals (SO 4 • − and •OH) and singlet oxygen were not the main reactive species and biochar-mediated electron transfer could be responsible for the degradation of ACP. This work provides a novel method for the degradation of pharmaceutical and personal care products through non-radical pathway and will be benefit for the development of efficient persulfate-based advanced oxidation processes.