Effects of bagasse-derived biochar aging on its performance for levofloxacin adsorption

The surface texture and chemical characteristics of biochar can be altered through natural aging processes, affecting its adsorption performance for antibiotics. In this study, chemical oxidation was used to age bagasse- derived biochar pyrolyzed at 500 degrees C to simulate its natural aging process. The results indicated that the aging process expanded the pore structure of the biochar and increased the specific surface area (SSA) from 10.0 m2/g to 20.7 m2/g. The oxidative aging process resulted in the destruction of aromatic structures in biochar accompanied by an increase in oxygen-containing functional groups, leading to an increase in its polarity. The adsorption of levofloxacin (LEV) by biochar increased significantly from 2.0 mg/g to 14.8 mg/g after oxidative aging process. The pseudo-second order kinetic model and the Freundlich isotherm model accurately described the adsorption behavior of LEV by biochar. The adsorption process was demonstrated to be predominantly governed by the chemisorption mechanism of the non-homogeneous multimolecular layer. Furthermore, the adsorption of LEV by bagasse-derived biochar was mainly attributed to hydrogen bonding and it-it interactions.