Retracted Article: Reductive immobilization of uranium by PAAM–FeS/Fe3O4 magnetic composites

Abstract

Ternary magnetic composites of poly(acrylamide)-stabilized FeS/Fe₃O₄ (denoted as PAAM–FeS/Fe₃O₄) were in situ synthesized by chemical coprecipitation of FeS/Fe₃O₄ in the presence of acrylamide (AAM), followed by dielectric barrier discharge (DBD) plasma-induced polymerization of AAM on the FeS/Fe₃O₄ surface. The modified PAAM improved greatly the stabilization and dispersion properties of PAAM–FeS/Fe₃O₄ in aqueous solutions. This as-prepared composite was applied as an adsorbent for the preconcentration of U(VI) cations from aqueous solutions. The maximum enrichment capacity of U(VI) on this adsorbent at pH 5.0 and 20 °C was calculated to be 311 mg g⁻¹. The presence of other cations had no obvious influence on the sorption of U(VI) on PAAM–FeS/Fe₃O₄, suggesting that this absorbent can remove U(VI) with high selectivity. According to the results of XPS spectra analysis, both FeS and amide groups on PAAM–FeS/Fe₃O₄ surfaces have strong chemical affinities to U(VI), and FeS can also reduce U(VI) to U(IV) effectively. The coagulation of magnetic U-laden PAAM–FeS/Fe₃O₄ can be easily separated and recovered from aqueous solution by simple magnet separation. This paper highlights the potential application of PAAM–FeS/Fe₃O₄ composites as suitable materials for the preconcentration and extraction of trace U(VI) ions from aqueous solutions in environmental radioactive pollution control and peaceful utilization of nuclear energy, such as the extraction of trace U(VI) ions from seawater.