Preparation of an amino-modified biochar supported sulfide nanoscale zero-valent iron composite and its efficient removal of U(vi) from wastewater by adsorption and reduction

Abstract

Nanoscale zero-valent iron (nZVI) was cured by vulcanization and biochar functionalization to overcome the tendency of oxidation and aggregation, and the sulfurized nano-zero-valent iron functional material supported by amino biochar (SnZVI–BC–NH₂) was obtained, which was used to remove U(VI) from wastewater in this study. A variety of measurements (SEM, TEM, XRD, BET, VSM, FT-IR, and XPS) were used to characterize the morphology, structure, magnetic properties, characteristic functional groups and chemical bonds of SnZVI–BC–NH₂. Analysis results confirm that the aminated biochar can support sulfurized nZVI well. The good kinetics, thermodynamics, and large removal capacity data (at pH 6, T = 298 K, Q_m = 158.1 mg g⁻¹) indicate that SnZVI–BC–NH₂ has excellent removal performance for U(VI), and the experimental data are in good agreement with the pseudo-second-order kinetic model. Cycling and anti-oxidation tests demonstrate that the FeS_x shell plays a crucial role in enhancing the removal of SnZVI–BC–NH₂ on U(VI). XPS and FT-IR analysis results show that SnZVI–BC–NH₂ removes U(VI) through the synergistic effect of adsorption and reduction.