Ultra high adsorption capacity of fried egg jellyfish-like γ-AlOOH(Boehmite)@SiO2/Fe3O4 porous magnetic microspheres for aqueous Pb(II) removal

Abstract

Fried egg jellyfish-like γ-AlOOH(Boehmite)@SiO₂/Fe₃O₄ porous magnetic microspheres were synthesized by a simple template-induced method. The products were characterized by X-ray diffraction (XRD) analysis , scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectrometry (EDS), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption–desorption techniques and vibrating sample magnetometry (VSM). Influencing factors, such as the concentration of reactants, the reaction temperature and the reaction time, were systematically investigated. The adsorption properties of the fabricated sample were investigated for aqueous Pb(II) removal. The maximum adsorption capacity (q_m) increased rapidly with an increasing void space in the shell of the microspheres, indicating that the void space is beneficial for increasing the adsorption properties of the material. The maximum adsorption capacity, q_m = 214.59 mg g⁻¹, is approximately 11.7-fold and 34.6-fold higher than SiO₂/Fe₃O₄ and Fe₃O₄ magnetic microspheres, respectively. The adsorption isotherm fitted the Langmuir model well and the square of the correlation coefficient was r² > 0.996. In addition, the effects of pH on the adsorption kinetics have also been investigated.