Preparation of Fe 3 O 4 @SiO 2 @MnO 2 microspheres as an adsorbent for Th(IV) removal from aqueous solution

A magnetic nano-composites Fe 3 O 4 @SiO 2 @MnO 2 were fabricated for efficient removal of Th(IV) from aqueous solutions, and characterized by SEM, TEM, XRD, FT-IR, BET, VSM, TGA and XPS. And the sorption of Th(IV) on Fe 3 O 4 @SiO 2 @MnO 2 were investigated as a function of pH, adsorbent dosage and initial Th(IV) concentration. The results showed that the adsorption maximum was 53.19 mg g −1 for Th(IV) at pH = 3.5 and T = 298 K. In addition, the adsorption kinetics followed the second-order kinetic model, and the adsorption isotherm could be perfectly depicted by the Langmuir model. Finally, XPS analysis illustrated that the lattice oxygen (M–O) and the surface hydroxyl oxygen (M–OH) participated in adsorption. In brief, the Fe 3 O 4 @SiO 2 @MnO 2 material could efficiently eliminate Th(IV) from aqueous solutions, which might become a promising material for adsorbing Th(IV) from environmental wastewater.