Removal of uranium from aqueous solutions using amine-functionalized magnetic platelet large-pore SBA-15

A novel amine-functionalized magnetic large-pore SBA-15 obtained via in situ approach and the post-grafting method was employed as a new adsorbent for removal of uranium from aqueous solutions. Results indicated that the as-prepared adsorbent exhibited fast adsorption rates in the first hour, at the optimum pH 6. The adsorption process was fitted well to the Langmuir isothermal and the maximum adsorption capacity obtained from the Langmuir model was 395.05 mg/g for NH2-M-SBA-15 sample. The kinetics of the uranium adsorption process over NH2-M-SBA-15 was described by pseudo-second-order kinetics. In comparison with the pristine large-pore SBA-15, the adsorption performance of NH2-M-SBA-15 was improved significantly. The thermodynamic parameters revealed that the adsorption of uranium on the material was spontaneous and endothermic. Furthermore, excellent recyclability could be achieved even after four consecutive adsorption-desorption cycles.