Refined regulation and nitrogen doping of biochar derived from ramie fiber by deep eutectic solvents (DESs) for catalytic persulfate activation toward non-radical organics degradation and disinfection

• EDSs achieved both fibrils separation and nitrogen introduction on biochar. • Water treatment and bacterial inactivation were realized by non-radical system. • Regular structure and aromatic compounds with N doping contribute to electron transfer. • Modification of DESs induce PDS activation pathway trend to direct electron-shuttle. • Direct two-electron transfer on PDS/NRBF/TC suffers less interference from (in)organics. Sulfate radical-based advanced oxidation process (SR-AOPs) has great promise in water treatment, there is thereby a pressing need yet still a significant challenge to rationally design an efficient and green catalyst for heterogeneous catalytic reactions. In this study, deep eutectic solvents (DESs) were prepared and employed to simultaneously achieve structural engineering of fibrils separation and surface modifying of nitrogen doping on biochar derived from filaments biomass (NRBF) of Ramie ( Boehmeria nivea (L.) Gaud). The more regular structure and pure carbon with reasonable configuration, and the N doped in hexatomic ring of NRBF were great impetus to improve the catalytic performance for peroxydisulfate (PDS) activation, with 4.5 times higher degradation rate of tetracycline than pristine biochar. The in-depth mechanistic study of PDS activation confirmed that dominated pathway was in transition from original reactive species ( 1 O 2 ) in pristine biochar system to a direct electron-shuttle pathway in NRBF system. Moreover, the non-radical dominated NRBF/PDS system showed good potential for bacteria ( Escherichia coli ) inactivation in disinfection application. Therefore, this work provides the underlying insights to guide the design of a functional and green biochar converting from Ramie filaments by an environmentally friendly facile protocol to achieve multiple purposes of wastewater decontamination and disinfection.