Synthesis of Magnetic Ferrites by the Dosing Mode of Fe2SO4 and Their Application for Cd(II) Removal from Aqueous Environment

Abstract

At 25℃ and pH value of 9.0, magnetic ferrite (F₁)was coated with ferrous sulfate (FeSO₄·7H₂O) to synthesize the F₂ by co-precipitation, which F₁ was prepared by ferrous sulfate. Then F₁ and F₂ were applied to remove Cd(II) from aqueous solutions. As-synthesized F₁ and F₂ were characterized by the settlement ratio, the Fe²⁺/Fe³⁺ ratio, XRD, SEM and VSM. The results were represented by the settlement rate of 10%, the Fe²⁺/Fe³⁺ ratio of 0.5. Several factors effecting the adsorption of Cd(II) ions were studied, including pH, contact time, the initial Cd(II) ions concentration and ammonia nitrogen concentration. Discussed on the adsorption kinetics and isotherm models of Cd(II) ions adsorption. The results revealed that the process of Cd(II) adsorption obeyed the pseudo-second order kinetic model and followed the Freundlich isotherm, indicating the Cd(II) adsorption was a chemical sorption, and the maximum adsorption capacity was 223.71mg/g. The Cd(II) ions adsorption increased with the increase of pH value, ferrite dosage and adsorption time, but ammonia nitrogen could restrain Cd(II) ions adsorption.