One-pot pyrolysis method for synthesis of Fe/N co-doped biochar as an effective peroxymonosulfate activator for RhB degradation

It was an effective method and research focus to remove recalcitrant organic pollutants by advanced oxidation processes based on persulfate activation with composite material as heterogeneous catalysts. Fe/N co-doped biochar (Fe/N-BC) was synthesized via one-pot calcination method with anhydrous FeCl3, melamine, and grape skin powder as precursors. Characterization results showed that biomass and melamine could anchor iron species on BC matrixes by coordination. The Fe/N0.1-BC exhibited significant activities toward peroxymonosulfate (PMS) activation, and 20 mg/L RhB can be degraded completely in 10 min with 0.05 g/L of the material and 0.5 g/L PMS. Electron paramagnetic resonance (EPR) study and free radical quenching experiments indicated that singlet oxygen (1O2), sulfate radicals (SO4•−), and hydroxyl radicals (•OH) were the main reactive oxidizing species, and non-radical mechanism and free radical process were considered to be involved in the degradation of the pollutants. Control experiments revealed that the enhanced active sites were mainly ascribed to rich defects as well as the synergistic effect among Fe and N doping into carbon substrate. The Fe/N-BC owned the merits of environmentally friendly raw materials, easy synthesis, and high activation efficiency, exhibiting splendid prospect for environmental application.