Anchoring nanoscale iron sulfide onto graphene oxide for the highly efficient immobilization of uranium (VI) from aqueous solutions

Uranium is one of the most important radioactive elements using in the nuclear technology application, but it is hazardous for environment and human health because of its high mobility and toxicity. Hence, designing effective materials for uranium immobilization is highly desirable. In this paper, a novel adsorbent of GO/FeS prepared using a simple and convenient manner, by anchoring graphene oxide on nanoscale FeS was investigated for the immobilization of U(VI) from aqueous solutions. The mechanism of U(VI) immobilized onto GO/FeS was unveiled by X-ray photoelectron spectroscopy (XPS). The results revealed that FeS nanoparticles were successfully anchored onto GO surface, resulting in more reactive sites than pristine FeS or GO. Impressively, it was found that GO/FeS can enhance the immobilization of U(VI), leading to high adsorption capacity up to 347.2 mg/g. The kinetics of U(VI) immobilization was in accordance with the pseudo-second order kinetic model, and the isotherm of U(VI) immobilization was described by the D–R model, indicating chemical interaction mainly contributed to U(VI) immobilization on GO/FeS. The synergy between surface adsorption and reduction/precipitation mainly accounted for the immobilization mechanisms of U(VI) on GO/FeS, making GO/FeS to be as potential materials for remediation of U(VI)-contaminated wastewater.