The preparation of amino-reinforced phosphorylated biochar for efficient uranium adsorption

Biomass transformation is considered as a green, economical and sustainable strategy in the field of wastewater treatment. Herein, we demonstrate a novel amino-reinforced phosphorylated biochar by the modified phosphoric acid (H 3 PO 4 )/urea/N,N-dimethylformamide method for highly effective U(VI) capture. The introduction of urea provides new amino sites on the surface of carbon and plays a decisive role in the phosphorylation modification of biochar. The adsorption process of the amino-reinforced phosphorylated biochar presents pseudo-second-order kinetics, and the maximum adsorption capacity calculated by Langmuir isotherm model can reach 150.38 mg g −1 . Moreover, the adsorbent still maintains an excellent removal efficiency after four adsorption–desorption recycles and shows superior selectivity. Structural analysis results after adsorption demonstrate that the adsorption performance of phosphorylated carbon is predominantly attributed to the chelating and electrostatic interaction.