Highly U(VI) immobilization on polyvinyl pyrrolidine intercalated molybdenum disulfide: Experimental and computational studies

In this study, polyvinyl pyrrolidine intercalated molybdenum disulfide (PVP/MoS2) with well-interconnected nanosheets were successfully prepared by an effective and versatile one-step hydrothermal strategy. The structural characterization indicated that the PVP molecules were intercalated into MoS2 to produce widened interlayer spacing. The obtained PVP/MoS2 nanomaterials exhibited impressive adsorption performance. Specifically, the maximum adsorption capacity of U(VI) on PVP/MoS2 (∼117.9 mg/g) was apparently superior than that of pristine MoS2 (∼23.7 mg/g) at 298 K and pH = 4.5, which might be related to the enlarged specific surface area and extensive functional groups of PVP/MoS2. The kinetics investigation showed that the uptake of U(VI) with PVP/MoS2 was ultrafast and the adsorption equilibrium could be reached within 10 min. The enrichment of U(VI) on PVP/MoS2 was caused by the existence of UO2-S covalent bonds and surface complexation with PVP, which was jointly verified by systematic investigation of FT-IR, XPS and DFT calculations. These findings were intriguing for both evaluating the adsorption performance of PVP/MoS2 and advancing other polymer interacted layered metal sulfides potential applications in the field of radioactive water treatment.