Uptake of uranium from wastewater by polyoxometalate modified graphene oxide

Owing to the development and utilization of nuclear energy, an excessive amount of containing uranium wastewater is generated and poses an environmental hazard. In this study, a novel polyoxometalate modified ammoniated graphene oxide (PHGO) was synthesized for the management of radioactive wastewater. The developed adsorbent was investigated by SEM/EDX, AFM, FT-IR, XRD, Raman, TAG and XPS techniques. The effects of pH, reaction time, initial U(VI) concentration, temperature, regeneration time, and co-existing ions on the removal of U(VI) by PHGO were explored. Results show that the maximum adsorption capacity of PHGO for U(VI) was 576 mg/g at pH 5.0, 298 K and 6 h under experimental conditions. In addition, PHGO displayed good stability and adsorption quantity only decreased from 199 mg/g to 150 mg/g after eight cycles. PHGO shows a high efficiency U(VI) removal of 95.4 % (C[U(VI)] = 100 μg /L) for wastewater with variety of metal ions and the residual U(VI) concentration (4.6 μg/L) in wastewater was lower than the most permissible concentration of uranium in drinking water (30 μg/L, World Health Organization). Overall, the PHGO was an excellent adsorbent for extracting uranium.