Novel N-doped hierarchically porous carbons derived from sustainable shrimp shell for high-performance removal of sulfamethazine and chloramphenicol

In this research, shrimp shell, as an abundant, environmental-friendly and renewable biomass source, was successfully converted into novel N-doped hierarchically porous carbons (N-HPCs) via a simple self-template carbonization and KOH activation. The physical-chemical properties of N-HPCs were characterized by FT-IR, SEM, TEM, Raman, BET and elemental analysis. The optimum N-HPCs (named N-HPC-850-2) exhibited the highest specific surface area (3171m²/g) and total pore volume (1.934cm³/g), and was used to effectively eliminate sulfamethazine (SMZ) and chloramphenicol (CAP) from water. Batch adsorption results showed increasing temperature was in favor of adsorption and the N-HPC-850-2 had a high adsorption affinity toward two antibiotics over a broad pH range. Adsorption isotherm data were fitted with Langmuir model very well, with the maximum monolayer adsorption capacity of 699.3 and 742.4mg/g for SMZ and CAP at 318K, respectively. The pseudo-second-order rate model described adsorption kinetics data well and adsorption processes were governed predominately by intra-particle diffusion and film diffusion. The thermodynamic parameters indicated the spontaneous and endothermic adsorption. Importantly, the N-HPC-850-2 adsorbent also exhibited a good regeneration capacity. Here, we provided a promising approach to prepare low-cost and high-performance biomass-based N-HPCs for fast and highly efficient removal of antibiotics from aquatic system.