Preparation of Polyamidoxime/Magnetic Graphene Oxide Composite and Its Application for Efficient Extraction of Uranium(VI) from Aqueous Solutions in an Ultrasonic Field

In this work, the polyamidoxime functionalized magnetic graphene oxide (mGO-PAO) was prepared via the surface-initiated reversible addition–fragmentation chain transfer (RAFT) polymerization, characterized by TEM, FT-IR, VSM, and TGA techniques, and applied for the extraction of uranium­(VI) from aqueous solutions in an ultrasonic field. The effects of pH, contact time, initial uranium­(VI) concentration, temperature, and competitive ions on the adsorption of U­(VI) were investigated. The adsorption speed of mGO-PAO for U­(VI) was found to be 18 times faster in the ultrasonic field than in the shaking mode, and the adsorption equilibrium, to be reached within 2 min. When the U­(VI) concentration was 10 mg/L, the temperature, 298 K, and pH, 6.0, the removal rate of U­(VI) reached 98.24% with high selectivity. The adsorption kinetics and isotherm data were well described by the pseudo-second-order and Langmuir models, respectively. The thermodynamic parameters suggested that the adsorption of U­(VI) was a typical spontaneous and endothermic process. XPS analysis suggested that the mGO-PAO bound the U­(VI) through the η2-N,O binding mode. Moreover, the mGO-PAO exhibits excellent adsorption performance in actual radioactive wastewater with an assist of ultrasound. This work provides a new approach for highly effective extraction of U­(VI) from the actual radioactive wastewater