Study on the adsorption of common antibiotics in water by cellulose-based adsorbents derived from sugarcane bagasse

Potassium acetate-modified cellulose biochar (PCB) derived from bagasse cellulose was utilized as an adsorbent. The adsorption performance and mechanism of PCB were evaluated using a typical mixture of antibiotics in simulated river water, including sulfamethoxazole (SMX), sulfadiazine (SMT), ofloxacin (OFL), ciprofloxacin (CIP), chloramphenicol (CAP), and florfenicol (FF). The PCB had a high specific surface area of 1693.22 m²/g. At 298 K, the maximum adsorption capacities of PCB for OFL, CIP, CAP, SMT, SMX, and FF were 158.492, 131.068, 76.391, 62.701, 38.802, and 33.417 mg/g, respectively. The adsorption of the six mixed antibiotics by PCB conforms to the pseudo-second-order kinetics and the Langmuir model. Competitive adsorption occurred among the mixed antibiotics, with OFL and CIP occupying the adsorption sites. The effect of pH on the adsorption capacity is significant. The adsorption mechanisms of typical antibiotics were investigated by integrating quantum chemical theoretical calculations. The contributions of electrostatic interactions, hydrogen bonding, and π-π interactions to the adsorption performance were quantitatively analyzed.