Chemical Activation of Forage Grass-Derived Biochar for Treatment of Aqueous Antibiotic Sulfamethoxazole

Abstract

Chemically activated forage Bermudagrass-derived biochar (A-BC) was produced, characterized, and utilized for adsorption of sulfamethoxazole (SMX) in water for the first time. After NaOH activation, A-BC showed a higher surface area (1991.59 m2/g) and maximum adsorption capacity for SMX (425 mg SMX/g BC) than those of various biochars and commercial activated carbons. The detailed analysis for adsorption of SMX onto A-BC indicated the efficient sorption of SMX through π-πEDA and hydrophobic and hydrogen bond interactions. Additionally, the adsorption of SMX on A-BC was limited by pore and liquid film diffusions. The SMX adsorption on A-BC was found to be endothermic and spontaneous from thermodynamic studies. Furthermore, the highly efficient regeneration of SMX-saturated A-BC over multiple cycles was achieved by NaOH-driven desorption, indicating that the adsorption of SMX onto A-BC would have high potential for cost-effective solution for elimination of SMX from water.