The use of chitosan/Fe3O4 grafted graphene oxide for effective adsorption of rifampicin from water samples

The environmental pollution caused by the introduction of antibiotics into the water resources poses serious threats to aquatic organisms and human health due to their toxicity and lasting harmful effects. In this research, the magnetized nanoparticles coated by chitosan (CS/Fe3O4) were grafted with graphene oxide (GO) to develop a biopolymer composite and study its efficiency for the removal of rifampicin (RIF), a semisynthetic antibiotic, from aqueous solution. The physiochemical properties of the GO/CS/Fe3O4 nanocomposite were characterized using the FTIR, XRD, FE-SEM, EDS, VSM, TGA, and BET analyses. The impacts of experimental parameters including the medium pH, contact time, adsorbent dosage, temperature, initial RIF concentration, and ionic strength on the adsorption efficiency were further investigated through batch experiments. The results indicated that in a solution with an initial RIF concentration of 20 mg L(-1)and a pH value of 5 at a temperature of 328 K, RIF removal efficiency was achieved higher than 95% using 10 mg of the GO/CS/Fe3O4 composite for a contact time of 75 min. The adsorption kinetics and isotherm were assessed using different models. The maximum adsorption capacity (q(max)) of the GO/CS/Fe3O4 was found to be 102.11 mg g(-1). Thermodynamic studies demonstrated the endothermic and spontaneous nature of the RIF adsorption. The high removal efficiency (over 70%) after seven successive adsorption-desorption cycles with the GO/CS/Fe3O4 showed the satisfactory regeneration performance of the adsorbent. Overall, the results of this study confirmed the capability of the GO/CS/Fe3O4 in enhanced removing RIF from aqueous media for environmental remediation applications.