Magnetic Nitrogen–Doped biochar for adsorptive and oxidative removal of antibiotics in aqueous solutions

Pollution by antibiotics has received attention worldwide because they are difficult to remove in wastewater. Extensive researches on antibiotics removal using adsorption and advanced oxidation processes has not resulted in ideal and effective methods for widespread implementation. Herein, nickel–containing and nitrogen–doped biochars (Ni@NBCs) are synthesized via polymer–assisted metal deposition and pyrolysis processes. These Ni@NBCs exhibit good adsorption capacities and act as catalysts to activate potassium persulfate (PPS) for producing reactive oxygen species, which react with the broad–spectrum antibiotic sulfachloropyridazine (SCP) in an oxidative degradation process. Experimental results of SCP adsorption confirm that the adsorption process follows pseudo–second–order kinetics and Langmuir isotherm models. Oxidative degradation results show that the constructed heterogeneous Ni@NBC/PPS system has excellent SCP degradation ability with degradation rates exceeding 90% within 40 min under certain conditions. The Ni@NBC also exhibits excellent reusability and durability (>75% degradation rate after 20 cycles). The catalytic mechanism and possible degradation pathways for SCP removal are proposed. Considering the adsorption and catalytic properties of Ni@NBCs, such materials show great application prospects for antibiotics removal in water environments.