Synthesis of magnetic graphene nanocomposites decorated with ionic liquids for fast lead ion removal

Seeking highly-efficient, low-cost and robust methods to remove metal ions from aqueous solutions is very much in demand. Here, we developed a novel magnetic composite bio-adsorbent, graphene oxide and magnetic chitosan-ionic liquids (GOMCS-ILs), for removing Pb(II) from water. This was the first time to combine ionic liquids and graphene oxide and magnetic chitosan, and apply to the adsorption of metal ions. The addition of ionic liquids can not only improve the dispersivity of the adsorbent, but also increase the adsorption sites. The characteristic result of FTIR, SEM, and XRD showed that GOMCS-ILs were prepared with large surface area and good magnetic responsiveness. The influence of various analytical parameters on the adsorption of Pb(II) such as pH, contact time, and initial ion concentration were studied in detail. The adsorption followed a pseudo second order kinetics. The equilibrium adsorption was well-described by the Langmuir isotherm model and the maximum adsorption capacity was to be 85 mg g−1. Moreover, the GOMCS-ILs could be repeatedly used by simple treatment without obvious structure and performance degradation. These results demonstrated the potential applications of GOMCS-ILs microspheres in efficient removal of Pb(II) from wastewater and deep-purification of polluted water.