Preparation of Biochar Carbonized With Sulfuric Acid and Study on Its Adsorption Properties to Antibiotics

Graphical This study presents a low-temperature sulfuric acid carbonization method to convert jacaranda husk into sulfonated biochar (JSS) with enhanced antibiotic adsorption. JSS exhibits superior adsorption capacities (161.76 mg g −1 for tetracycline, 63.96 mg g −1 for ciprofloxacin) via synergistic mechanisms: electrostatic attraction, π–π interactions, and hydrogen bonding. The material retains > 80% efficiency after five regeneration cycles, offering a sustainable solution for water pollution remediation. In this study, an innovative low-temperature sulfuric acid carbonization method was developed to convert agricultural waste jacaranda husk into high-performance biochar (JSS), which overcomes the problems of surface ash coverage and functional group loss caused by traditional high-temperature pyrolysis (>500 °C). By introducing a sulfonic acid group (-SO₃H) and retaining abundant oxygen-containing functional groups (-OH, -COOH), the adsorption capacity of JSS for tetracycline (TC) and ciprofloxacin (CIP) reached 161.76 and 63.96 mg g −1 , respectively, which was about three times higher than that of conventional pyrolysis biochar (JST). Experiments show that JSS exhibits the best adsorption performance in the pH range of 6–7, and efficient removal is achieved through the synergistic action of electrostatic attraction, π–π interaction, and hydrogen bonding. In addition, the adsorption efficiency of JSS remained above 80% after five regeneration cycles, demonstrating excellent stability and reusability.