Constructing Stable N-Doped Iron-Based Porous Carbon Nanocatalyst for Antibiotic Degradation and Bactericidal Detoxification

Abstract

N-doped iron-based carbon is a promising catalyst to achieve peroxydisulfate (PDS) activation, but constructing efficient and stable N-doped iron-based carbon catalysts with uniformly distributed and firmly anchored nitrogen and iron sources remains challenging. Herein, we developed a stable N-doped magnetic porous carbon (NMPC) catalyst through self-polymerization and high-temperature pyrolysis of polydopamine and Fe³⁺ coordination complexes and explored it for PDS activation in antibiotic (tetracycline (TC) and ciprofloxacin) degradation and bactericidal detoxification. The NMPC/PDS system performed both radical and nonradical catalytic pathways for effective PDS activation, exhibiting 99.8% removal of TC. Thanks to the strong coordination of polydopamine with Fe³⁺, the resulting NMPC could firmly confine iron species in the porous N-carbonaceous matrices and efficiently prevent severe iron leaching, demonstrating good recyclability. It could maintain a removal rate as high as 92.4% after 5 cycles. After cycling, the iron leaching of the NMPC catalyst is only 0.026 mg/L, which is much lower than the WHO guideline value limits for drinking water of 0.3 mg/L. Moreover, the NMPC catalyst exhibits excellent stability and compatibility with various water conditions, including pH variations (3–9), coexisting substances, and different water sources. In addition, this NMPC/PDS system exhibits an excellent disinfection of both Escherichia coli and Staphylococcus aureus, with a high disinfection ratio of more than 99.9%. Toxic intermediate prediction and cell toxicity experiments further prove that the toxicity of the TC wastewater is significantly reduced after the treatment with the NMPC/PDS system.