Synthesis of phosphonic acid and carboxyl functionalized core-shell magnetic polymer nanocomposite for the synergistic removal of uranium from wastewater.

Developing core-shell structured magnetic nanocomposite to remove uranium from wastewater is of importance for protecting the environment while ensuring the sustainable use of nuclear energy. Herein, a novel bifunctional core-shell magnetic polymer nanocomposite Fe3O4/P (MBA-BMP-AA) was developed by distillation-precipitation polymerization of N, N'-methylene diacrylamide (MBA), bis(2-methacryloxyethyl) phosphate (BMP) and acrylic acid (AA) on the surface of Fe3O4 modified by KH570 for disposing wastewater containing uranium. The controlled experiments and characterizations verified the collaborative interplay of phosphonic acid and carboxyl endowed Fe3O4/P (MBA-BMP-AA) with marvelous uranium removal performance. The composite not only demonstrated a maximum adsorption capacity (qmax) of 436. 1 mg g-1 for uranium at pH 4.5, but exhibited strong selectivity for uranium in the presence of other metal ions, and the separation factor (SU/M) of uranium for competing metal ions transcended 44.1. Also, Fe3O4/P (MBA-BMP-AA) could be facilely magnetically separated, and be repeatedly used at least six times with no visible reduction for removal performance. What's more, the vestigial uranium concentration in the disposed real wastewater could be decreased to below 0.03 mg L-1, which met the discharge standard. The removal of uranium primarily relied on electrostatic interactions and the surface chemical complexation, verified by the controlled experiments and characterizations. These findings demonstrated that Fe3O4/P (MBA-BMP-AA) represented a candidate for the removal of uranium from wastewater.