Highly Efficient Removal of Uranium from an Aqueous Solution by a Novel Phosphonic Acid-Functionalized Magnetic Microsphere Adsorbent

The development of adsorption materials which can efficiently isolate and enrich uranium is of great scientific significance to sustainable development and environmental protection. In this work, a novel phosphonic acid-functionalized magnetic microsphere adsorbent Fe₃O₄/P (GMA-MBA)-PO₄ was developed by functionalized Fe₃O₄/P (GMA-MBA) prepared by distill-precipitation polymerization with O-phosphoethanolamine. The adsorption process was endothermic, spontaneous and kinetically followed the pseudo second-order model. The maximum uranium adsorption capacity obtained from the Langmuir model was 333.33 mg g^-1 at 298 K. In addition, the adsorbent also had good acid resistance and superparamagnetic properties, which could be quickly separated by a magnetic field. XPS analysis showed that the adsorption of adsorbent mainly depended on the complexation of phosphonic acid group with uranium. This work offers a promising candidate for the application of magnetic adsorbents in the field of uranium separation and enrichment.