Activation of peroxymonosulfate by sewage sludge biochar-based catalyst for efficient removal of bisphenol A: Performance and mechanism

Abstract

Activation of peroxymonosulfate (PMS) for organic-contaminated water remediation is a promising strategy. In this study, a sludge-derived biochar (SBC) was prepared as an efficient and low-cost metal-free catalyst to activate PMS for the abatement of bisphenol A (BPA) in water. The results demonstrate that BPA could be rapidly oxidized by the combination of SBC and PMS. Compared with the slight adsorption (8.1%) by SBC alone and limited direct oxidation (2.4%) by sole PMS, the removal efficiency of BPA was boosted to 94.5% within 60 min in the presence of both SBC and PMS. Active species participating in the rapid elimination of BPA were investigated via both chemical quenching experiment and electron paramagnetic resonance (EPR) technique. The results indicate that non-radical rather than radical process plays an important role in BPA abatement in the SBC/PMS system. The electron-transfer non-radical process was further verified by the open circuit potential test. It is proposed that PMS is bound to SBC to form a surface reactive complex (SBC-PMS*), which would abstract the electrons from the adsorbed BPA through the conductive carbon tunnel. The present work provides an alternative of controlling waste by waste.