Efficient adsorption of ciprofloxacin using Ga2S3/S-modified biochar via the high-temperature sulfurization

• Ga 2 S 3 /S-modified biochar (Ga/S-BC) was prepared by high-temperature sulfurization. • Ga/S-BC exhibited the efficient adsorption capacity for ciprofloxacin removal. • Electrostatic interaction was vital for the physisorption process of Ga/S-BC. Ga 2 S 3 and sulfur co-modified biochar (Ga/S-BC) composites were prepared for enhancing the adsorption of ciprofloxacin from sugarcane bagasse via the high-temperature sulfurization. In contrast with sulfur-modified biochar, Ga/S-BC exhibited the better adsorption capacity for ciprofloxacin removal. The increasing Ga content induced to the climbing and then declining adsorption activity of Ga/S-BC. Among these obtained Ga/S-BC composites, optimal 3-Ga/S-BC with a Ga content of 7.40% and surface area of 681.67 m 2 g −1 exhibited the superior capacity of 330.21 mg g −1 . The adsorption capacity of 3-Ga/S-BC declined to 301.66 mg g −1 after nine cycles. pH and inorganic salts also affected the adsorption capacity of 3-Ga/S-BC for ciprofloxacin removal. The adsorption isotherms of obtained Ga/S-BC composites were well described by Langmuir isotherm, and their adsorption kinetics were well estimated via second-order model. The adsorption performance of 3-Ga/S-BC in ciprofloxacin removal was a physisorption and spontaneous process.