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Zirconium-based ferromagnetic sorbent was fabricated by coprecipitation of Fe2+/Fe3+ salts in a zirconium solution and explored as a potential sorbent for removing the Cu2+, Zn2+, and Cd2+ from aqueous solution. The sorbent could easily be separated from aqueous solution under the influence of external magnetic field due to the ferromagnetism property. A trimodal distribution was obtained for the sorbent with average particle size of 22.74 μm. The –OH functional groups played an important role for efficient removal of divalent ions. The surface of the sorbent was rough with abundant protuberance while the existence of divalent ions on the sorbent surface after the sorption process was demonstrated. Decontamination of the heavy metal ions was studied as a function of initial metal ions concentration and solution pH. Uptake of the heavy metal ions showed a pH-dependent profile with maximum sorption at around pH 5. The presence of the ferromagnetic sorbent in solution at different initial pH has shown a buffering effect. Equilibrium isotherms were analyzed using Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherm models. Adequacy of fit for the isotherm models based on evaluation of R2 and ARE has revealed that heavy metal ions decontamination was fitted well with the Freundlich model. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a zirconium-based magnetic sorbent is developed by a coprecipitation technology. The characterization of the sorbent and its adsorption behavior are systematically investigated. It is shown that the sorbent has a small mean diameter of 543.7nm, a specific surface area of 151m2/g, and a pHzpc of 7. The sorbent has a rough surface and many pores developed on the surface. It has a molecular formula of ZrO(OH)2·1.6Fe3O4·2.5H2O, which was determined by the thermal gravimetric analysis, the elemental analysis, and the digestion experiments. The sorption equilibrium can be reached within 25h. Better adsorption can be obtained at lower pH, and the optimal initial pH is from 2.6 to 3.3. The maximum adsorption capacity of 45.6mg-As/g is achieved, which is much higher than many reported sorbents. FTIR spectra analysis indicates that –OH groups play an important role in the uptake. Some of the arsenate are reduced to arsenite after its adsorption onto the magnetic sorbent; the divalent iron in the sorbent may provide electrons for the reduction. A conceptual model for the adsorption of arsenate by the magnetic sorbent is proposed to illustrate the mechanism. [Copyright &y& Elsevier]