Facile preparation of S-doped magnetite hollow spheres for highly efficient sorption of uranium(vi)

Magnetite sorbents (MS) have been widely employed for water purification; however, adsorption capacity loss frequently occurs during the formation of magnetite sorbents. In this study, we report the preparation of S-doped magnetite hollow spheres (S-doped MHS) used for the removal of UO₂²⁺ with a large adsorption capacity of 450.0 mg U per g, higher than that of pure Fe₃O₄. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM) were used to determine the effectiveness of the synthesis of S-doped MHS. The S-doped MHS was investigated for the adsorption of uranium(vi) from an aqueous solution. In addition, the adsorption process fits the Freundlich isotherm model and pseudo-second-order rate equation perfectly. The affinity and selectivity of S-doped MHS for uranium(vi) is significantly high. S-doped MHS can be easily separated using an external magnetic field. Moreover, S-doped MHS can be used for the adsorption of other heavy metal ions, which indicates their promising potential applications as adsorbents in aqueous solutions.