Neglected but Efficient Electron Utilization Driven by Biochar-Coactivated Phenols and Peroxydisulfate: Polyphenol Accumulation Rather than Mineralization

• DOI: 10.1021/acs.est.3c00022
• Publication Date: 2023-03-18T12:53:52Z
• Authors: Jibo Dou; Yao Tang; Zhijiang Lu; Guangzhi He; Jianming Xu; Yan He
• Keywords: Peroxydisulfate; Electron acceptor

We report an unrecognized but efficient nonradical mechanism in biochar-activated peroxydisulfate (PDS) systems. Combining a newly developed fluorescence trapper of reactive oxygen species with steady-state concentration calculations, we showed that raising pyrolysis temperatures biochar (BC) from 400 to 800 °C remarkably enhanced trichlorophenol degradation inhibited the catalytic production radicals (SO4•– and •OH) water soil, thereby switching radical-based activation into electron-transfer-dominated pathway (contribution increased 12.9 76.9%). Distinct previously reported PDS* complex-determined oxidation, situ Raman electrochemical results this study demonstrated simultaneous phenols PDS on surface triggers potential difference-driven electron transfer. The formed phenoxy subsequently undergo coupling polymerization reactions generate dimeric oligomeric intermediates, which are eventually accumulated removed. Such unique nonmineralizing oxidation achieved ultrahigh utilization efficiency (ephenols/ePDS) 182%. Through molecular modeling theoretical highlighted critical role graphitic domains rather than redox-active moieties lowering band-gap energy facilitate Our work provides insights outstanding contradictions controversies related inspiration for more oxidant-saving remediation technologies.