Scalable Fe@FeO core-shell nanoparticle-embedded porous wood for high-efficiency uranium(VI) adsorption

Abstract The effective removal of toxic and radioactive uranium (VI) (UO22+) is very important for environmental protection and human health. Nevertheless, there is a lack of scalable adsorption materials for high-efficient and cost-effective removal of UO22+ from water. In the present work, Fe@FeO core-shell nanoparticle (NP)-embedded wood is utilized for adsorption of UO22+ from stimulated wastewater. The effect of various experimental conditions such as pH, reaction time, reaction temperature, and UO22+ are investigated. The maximum adsorption capacity of UO22+ is obtained at pH 4 (2.08 g UO22+ of g Fe@FeO NPs), which is comparable to that of the reported FeNP and much higher than other Fe-containing nanoparticles for UO22+ adsorption. The adsorption mechanism is ascribed to the redox reaction between Fe@FeO nanoparticles and UO22+, which reduce UO22+ to UO2 that is immobilized at the center of nanoparticles, while the wood matrix provides a support and does not adsorb UO22+. Meanwhile, the Fe@FeO NP-embedded wood is able to float on the surface of wastewater, which is easily separated and reused. More importantly, the low-cost Fe@FeO NP-embedded wood allows for scalable preparation, further improving the adsorption performance toward UO22+ using the large-scale wood for future practical applications.