Magnetically separable CoFe2O4/CoxFey/activated carbon composites for Cd(II) removal from wastewater

CoFe2O4 and CoxFey were anchored into activated carbon (AC) to synthesize CoFe2O4/CoxFey/AC composites using the sol-gel method for Cd(II) adsorption from wastewater. The results indicated that CoFe2O4 and CoxFey nanoparticles existed in the pores of AC. The magnetic properties of CoFe2O4/CoxFey/AC indicated it could be separated and retrieved easily using an external magnet after Cd(II) adsorption. The effects of solution pH, temperature and initial Cd(II) concentration on the Cd(II) adsorption of AC and CoFe2O4/CoxFey/AC were investigated. The standard free energy, enthalpy change and entropy change were evaluated. The kinetic parameters of Langmuir and Freundlich isothermal equation were analyzed, and the Freundlich kinetic model was feasible for describing the Cd(II) adsorption process of CoFe2O4/CoxFey/AC composites.