Kelp-derived N-doped biochar activated peroxymonosulfate for ofloxacin degradation.

N-doped carbon materials have been proven to be effective catalysts for activating peroxymonosulfate (PMS). Marine algae biomass is rich in nitrogenous substances , which can reduce the cost of N-doping process and can obtain excellent N-doped catalysts cheaply and easily. In this study, kelp biomass was selected to prepare N-doped kelp biochar (KB) materials. The high defect degree, high specific surface area, and participation of graphite N make KB have excellent catalytic degradation ability. The KB degraded 40 mg/L ofloxacin (OFL) close to 100% within 60 min, applied with PMS. Through quenching experiments and electron paramagnetic resonance spectroscopy, the degradation process dominated by non-radical pathways was determined. At the same time, O2·- and 1O2 were closely related, and a significant impact of quenching O2·- on the reaction was observed. The non-radical approach made the system excellent performance over a wide pH range and in the presence of multiple anions. The experiments of reusability confirmed the stability of the material. Its catalytic performance was restored after low-temperature pyrolysis. This research supports the use of endogenous nitrogen in biomass. It provides more options for advanced oxidation process application and marine resource development.