Facile construction of Fe, N and P co-doped carbon spheres by carbothermal strategy for the adsorption and reduction of U(vi)

Abstract

In this work, nitrogen and phosphorus co-doped magnetic carbon spheres encapsulating well-dispersed active Fe nanocrystals (Fe/P-CN) were fabricated via a simple copolymer pyrolysis strategy. Benefiting from heteroatoms doping, Fe/P-CN could primarily adsorb soluble U(VI) ions through abundant functional groups, and subsequently, the adsorbed U(VI) could be reduced to insoluble U(IV) by Fe nanocrystals. Fe/P-CN pyrolyzed at 800 °C (Fe/P-CN-800) exhibited excellent U(VI) removal capacity of 306.76 mg g⁻¹, surpassing nitrogen and phosphorus co-doped carbon spheres and nano zero-valent iron. In addition, the magnetic separation and thermal reactivation properties endow Fe/P-CN-800 with excellent reusability. This research, especially, provides a promising synergistic adsorption and reduction strategy to effectively remove U(VI) using heteroatom-doped composites.