Study of the removal of ciprofloxacin by Zn–GO@SA aerogel microspheres

Graphene oxide (GO) has the advantages of a high specific surface area and great mechanical properties, which make it useful in the field of adsorption; however, it is difficult to obtain and utilize nano-size GO for adsorption and separation. In this study, zinc ion crosslinked GO and sodium alginate aerogel microspheres (Zn–GO@SA) were prepared using the ion–gel method and used for ciprofloxacin (CIP) adsorption, and this was easy to separate and collect from solutions. Methods such as SEM, EDX, FT-IR, and TGA were used for physical and chemical characterization. The adsorption properties and mechanisms were examined via static and dynamic adsorption experiments. The results indicated that the Zn–GO@SA aerogel microspheres had abundant and ordered cavities. The adsorption isotherm and kinetic data fitting results showed that the adsorption process was consistent with the Freundlich model and a quasi-second-order kinetics model. The adsorption of CIP was a multi-layer adsorption process dominated by chemical adsorption. At 308 K, the maximum adsorption capacity was 134.85 mg g−1, while increasing the adsorption temperature had an adverse effect on CIP adsorption. The results of regeneration and dynamic adsorption experiments showed that Zn–GO@SA aerogel microspheres maintained good adsorption performance after repeated use, which means they have potential for practical applications.