Relying on the non-radical pathways for selective degradation organic pollutants in Fe and Cu co-doped biochar/peroxymonosulfate system: The roles of Cu, Fe, defect sites and ketonic group

Abstract

• Fe and Cu co-doped biochar (FeCu-MSBC) was prepared using mild pyrolysis conditions. • FeCu-MSBC/peroxymonosulfate (PMS) system selectively degraded contaminants. • The humic acid in sewage accelerated degradation process in FeCu-MSBC/PMS system. • The enhancement effect of doped Fe and Cu on carbon promoted the catalysis. • The whole degradation process was controlled by non-radical pathways. The green and low-cost heterogeneous peroxymonosulfate (PMS) systems with non-radical degradation pathways have a huge applied potentiality in actual water treatment. In present study, low concentration Fe and Cu co-doped biochar (FeCu-MSBC) was successfully acquired using moderate pyrolysis temperature, and employed it to activate PMS for degrading organic pollutants. The experimental results proved that the FeCu-MSBC/PMS system possessed the selective degradation for electron-rich pollutants, the outstanding resistance for interferences in actual bodies and the good regeneration performance. Besides, the possible degradation pathways of RhB in the system were explored. Meanwhile, the specific enhancement effect was found, which could be summarized as Cu doping effectively improving adsorption capacity, Fe doping greatly reducing electrical impedance and Fe and Cu co-doping increasing active sites of FeCu-MSBC. The non-radical pathways including singlet oxygen ( 1 O 2 ) and electron transfer mediated by FeCu-MSBC controlled the whole degradation process, and the Cu, Fe, ketonic groups (C = O) and defective sites played significant roles in activating PMS and degrading pollutants. This work was helpful for developing metals co-doped carbon-based catalyst/PMS systems to selectively degrade pollutants by non-radical oxidation.