Levofloxacin Removal in Aquatic System Using Swine Manure-Derived Biochar

This study investigated the physicochemical properties of swine manure (SM)-derived biochar (BC), and its adsorption capacity for levofloxacin (LEV). Raw SM exhibited a BET surface area of 0.46 m²/g, a pore volume of 0.0007 cm³/g, and a pore size of 62.50 Å. In contrast, SM-BC produced via pyrolysis (600^oC, 3 h) showed a significantly higher BET surface area (362.48 m²/g), approximately 788 times greater than that of raw SM. Pore volume increased to approximately 0.028 cm³/g, while pore size decreased to 33.68 Å. Adsorption kinetic analysis indicated that the pseudo-second order (R² = 0.92) and Elovich models (R² = 0.94) fitted experimental data better than the pseudo-first order model (R² = 0.56), suggesting that LEV adsorption onto SM-BC is primarily governed by chemisorption rather than physisorption. The Freundlich isotherm model demonstrated a better fit (R² = 0.96) than the Langmuir model (R² = 0.85), indicating multilayer LEV adsorption on a heterogeneous surface. The maximum adsorption capacity of SM-BC for LEV is 148.65 mg/g, higher than that of various other adsorbents (2.71–41.35 mg/g) and comparable to commercial activated carbons (82–164 mg/g). Collectively, these results suggest that SM-BC has strong potential as an adsorbent for the removal of levofloxacin from aqueous environments.