β-Cyclodextrin Functionalization of Nitrogen-Doped Graphene to Enhance Dispersibility and Activate Persulfate for Trace Antibiotic Degradation in Water

The functionalization of nitrogen-doped graphene with β-Cyclodextrin (designated β/N-rGO) was employed to enhance the dispersibility of graphene materials and to establish an adsorption-catalytic oxidation system using peroxymonosulfate (PMS) for the removal of trace antibiotics from water. The experimental results indicated that β-Cyclodextrin was effectively dispersed on the support structure of nitrogen-doped graphene, which enhanced the specific surface area and dispersibility of the material. The adsorption-catalytic oxidation system comprising β/N-rGO and PMS degraded 92.35% of sulfamethoxazole within 12 min and exhibited significant removal efficiency for sulfonamides, quinolones, macrolides, tetracyclines, β-lactams, and chloramphenicol antibiotics across a pH range of 3–12. The reaction time was reduced by over 10% compared to the unmodified material, with a more pronounced improvement in treatment efficiency, particularly under low-pH conditions. The activation energy of β/N-rGO was estimated to be approximately 4.5 kJ/mol, and elevated temperatures accelerated the reaction, with the removal rate remaining above 85% after five regeneration cycles. Quenching experiments and EPR spectra confirmed that the primary pathway for PMS activation by β/N-rGO was a non-radical process dominated by singlet oxygen. These findings broaden the research and application scope of cyclodextrin–graphene interactions and provide a feasible approach for the removal of trace antibiotics from water.