Removal of cobalt ion from aqueous solution using magnetic graphene oxide/chitosan composite

The magnetic graphene oxide (GO)/chitosan composite was prepared, characterized, and applied for the removal of cobalt ions from aqueous solutions. One‐step coprecipitation method was used to synthesize magnetic GO/chitosan beads, which were characterized by VMS, FTIR, SEM, and EDX. The composites show a good porous structure and magnetic separation ability. The adsorption process is endothermic (ΔH 0 = 12.08 kJ mol −1 ) and pH in the range of 5–9 has a slight effect on Co 2+ adsorption. The adsorption kinetic data could be fitted with the pseudo‐second‐order model (R 2 = 0.995) best, followed by the intraparticle diffusion (R 2 = 0.950) and pseudo‐first‐order (R 2 = 0.943) models. In addition, the Langmuir model (R 2 = 0.995) was better at fitting the adsorption equilibrium data than that of the Freundlich (R 2 = 0.814) and the Temkin (R 2 = 0.806) models. The maximum adsorption capacity (q m ) was calculated to be 15.24 mg·g −1 based on the weight of chitosan and GO by the Langmuir model. The magnetic GO/chitosan composite beads can be used for the removal of cobalt ions from aqueous solutions. © 2018 American Institute of Chemical Engineers Environ Prog, 38: S32–S41, 2019