Waste-to-adsorbent strategy: Bagasse-derived hemicellulose functionalized graphene oxide for the efficient removal of chlortetracycline from aqueous media

A sustainable waste-to-adsorbent strategy was developed using hemicellulose functionalized graphene oxide (HC-GO) for the adsorption-based removal of the antibiotic chlorotetracycline (CTC) from water, where hemicellulose was extracted from discarded sugarcane bagasse and the precursor of graphene oxide (GO) was graphite recovered from waste dry cell batteries. The synthesized HC-GO was characterized by SEM-EDS, TEM, XRD, FTIR, DLS which confirmed the successful preparation of HC-GO from waste materials. Batch adsorption experiments were conducted to optimize the operational parameters, revealing that at pH 5 with an adsorbent dosage of 0.1 g L -1 , an initial CTC concentration of 0.2 mg L -1 , and an equilibrium time of 15 minutes, over 98% of CTC was removed from water. The adsorption process was well described by the Freundlich isotherm and followed Pseudo-second-order kinetics. Thermodynamic analysis showed the adsorption process was exothermic and spontaneous over the temperature range of 30-50 °C, indicating a thermodynamically favorable process. The HC-GO adsorbent demonstrated excellent reusability over eight cycles which highlights its potential as a cost-effective material. The novelty of this study lies in valorizing sugarcane bagasse and waste dry cell batteries to produce a low-cost, green adsorbent. Overall, HC-GO exhibits outstanding adsorption performance, sustainable reusability, and practical applicability for mitigating antibiotic contamination in aqueous environments.