Novel mesocellular silica foam supported poly(amidoxime-ethyleneimine) network for fast and highly efficient uranium extraction from seawater

According to the global vision of "carbon peak and carbon neutrality", extracting uranium from natural seawater is regarded as a promising candidate for meeting nuclear fuel demand. Nevertheless, owing to the very low uranium concentration and complexity of natural seawater, the development of adsorbent materials for extracting uranium from seawater with satisfactory efficiencies remains a great challenge. In this work, we for the first time developed a novel mesocellular silica foam (MSF) supported hyperbranched poly(amidoxime-ethyleneimine) (PAO-PEI) network (MSF@PAO-PEI). After systematic evaluation, the MSF@PAO-PEI exhibited high adsorption capacity and excellent reusability, fast adsorption kinetics as well as good adsorption selectivity and affinity towards uranyl ions, simultaneously. Besides the obtained short equilibrium time of -20 h, the MSF@PAO-PEI achieved a remarkable adsorption capacity of 926.2 mg-U/g-Ads. for 100 mg/L of uranium water solution. Meanwhile, the MSF@PAO-PEI showed evident higher selectivity towards uranium (29.3 mg g-1) against vanadium (7.2 mg g-1) and other coexisting metal ions in simulated seawater. Moreover, excellent reusability of MSF@PAO-PEI in eight consecutive adsorption-desorption cycles was also observed. More importantly, satisfactory extraction efficiencies (90.6-92.9 %) for U-spiked real seawater was obtained in 48 h. Finally, a uranium adsorption capacity of 1.102 mg g- 1 for coastal seawater in 20 days was obtained. All these findings demonstrate the relatively good potential of MSF@PAO-PEI for extracting uranium from real seawater.