High-efficiency removal of U(VI) from low-concentration uranium-bearing wastewater using ZnCl2-modified activated carbon loading nZVI.

ZnCl₂-modified activated carbon supported nanoscale zero-valent iron material (nZVI/BC600) was synthesized by green carbothermal reduction and liquid phase reduction to explore the removal efficiency of U(VI) under different conditions. The results showed that under the optimal conditions (C₀ = 10 mg/L, C/Fe = 5:1, pH = 5.5, t = 30 min), the removal rate of U(VI) by nZVI/BC600 was 99.68%, which was 9.18% higher than that of ZnCl₂-modified activated carbon and conformed to the pseudo-second-order kinetic model. SEM and XPS analysis showed that nZVI was uniformly distributed on activated carbon, and U(VI) was reduced to U(IV) or U(V). The removal mechanism of U(VI) by nZVI/BC600 is chemical adsorption, redox and co-precipitation. [ABSTRACT FROM AUTHOR]