Removing Efficiency and Mechanism of Ciprofloxacin from Aqueous Solution Using Rectorite

This work found that rectorite (REC) has a good adsorption effect on cationic pollutants such as ciprofloxacin (CIP), with a maximum adsorption capacity of 79.73 mg/g for CIP. The zeta potential analysis showed that the electronegativity of the REC surface would be weakened after CIP adsorption under acidic conditions. Through adsorption kinetics, isotherm study, XRD, FTIR, and other characterizations, the phenomenon of reduced negative charge on the surface of REC adsorbed with CIP under acidic conditions was explained. Based on the Langmuir and Temkin models, the adsorption process of CIP on REC is a spontaneous endothermic adsorption process. The adsorption kinetics can be better described using a pseudo-second-order model, indicating that the adsorption rate is mainly controlled by chemical adsorption. The characterization further proved that REC adsorbed ciprofloxacin mainly through hydrogen bonding, cation exchange, and electrostatic gravitational interaction. CIP, as an emerging contaminant discharged into the water environment, will be harmful to the ecological environment and human health. Therefore, the utilization of REC for the removal of CIP from an aqueous solution has potential prospects.