Facile preparation of EDTA-functionalized magnetic chitosan for removal of co(II) from aqueous solutions.

In this study, an efficient adsorption and reusable magnetic ligand material (FeO@Chitosan-EDTA) was synthesized by binding EDTA dianhydride onto magnetic chitosan, and it was employed in removal of Co(II) from aqueous solution. The maximum adsorption capacity of Co(II) onto FeO@CS-EDTA was 48.78 mg/g at pH = 5 (303 K), which is much higher than that of FeO@Chitosan as well as chitosan. The kinetics of Co(II) on the FeO@CS-EDTA was consistent with the pseudo-second-order model. The equilibrium data were better fit with the Langmuir isothermal model than with the Freundlich isothermal model, suggesting that the adsorption mechanism was chemical monolayer homogeneous adsorption. The thermodynamic data showed that the sorption of Co(II) was spontaneous. Furthermore, after four cycles, the adsorption capacity of Co(II) onto the FeO@CS-EDTA still retained 84.5% of the capacity of the fresh adsorbent, indicating that FeO@CS-EDTA can be considered a promising recyclable adsorbent to remove heavy-metal ions from wastewater.