Nitrogen-doped flower-like porous carbon nanostructures for fast removal of sulfamethazine from water.

The increasing concern for the toxicity of sulfamethazine (SMT) in water requires the establishment of effective water treatment processes to remove it. In this study, a novel adsorbent of nitrogen-doped flower-like porous carbon nanostructures (N-doped FPC) was proposed for the adsorption removal of SMT. The N-doped FPC possessed high surface area, good water dispersibility, and alkaline surface, endowing it with great adsorption efficiency towards SMT. The adsorption equilibrium data can be well fitted by both the Langmuir and Temkin models, and the maximum monolayer adsorption capacity of N-doped FPC was 610 mg g for SMT at 298 K. The N-doped FPC exhibited fast adsorption rate for SMT and adsorption equilibrium reached within only 5 min. The pseudo-first-order model described adsorption kinetics data well and the external mass transport was the rate-limiting step. The thermodynamic parameters (ΔG, ΔH, and ΔS) showed that the adsorption of SMT onto N-doped FPC was a feasible, spontaneous, and endothermic physisorption process. After five consecutive sorption/desorption cycles, the N-doped FPC retained more than 85% adsorption capacity. This study confirmed the promising potential of N-doped FPC as high-performance adsorbents for water purification.