Facile Synthesis and Characterization of Zn(II)-Impregnated Chitosan/Graphene Oxide: Evaluation of Its Efficiency for Removal of Ciprofloxacin from Aqueous Solution

Zn(II)-impregnated chitosan/graphene oxide composite (Zn(II)-CS/GO) was prepared and applied for adsorptive removal of ciprofloxacin (CFN) from aqueous solutions. The material was characterized by FTIR, XRD, SEM coupled with EDX, and TGA-DTA. The experimental variables were optimized by Box-Behnken design. Under optimized conditions, the adsorption capacity of Zn(II)-CS/GO for CFN was 210.96 mg/g at pH 6.5. The experimental adsorption data fitted well to Langmuir model with R-2 >= 0.9914. The sorption kinetic data were well described by pseudo-second-order kinetic model (R-2 >= 0.9989). Elovich model with R-2 (>) 0.986 indicated towards the chemical nature of adsorption. The adsorption of CFN on the adsorbent occurs through electrostatic and pi-pi interactions. The values of thermodynamic parameters (Delta G degrees, Delta S degrees, and Delta H degrees) indicated that the sorption of CFN on the Zn(II)-CS/GO was an endothermic and spontaneous process. Adsorption-desorption studies suggested that the Zn(II)-CS/GO composite can be used effectively for CFN removal from water.