In-situ anchoring of pyrrhotite on graphitic carbon nitride nanosheet for efficient immobilization of uranium.

Enrichment of U-VI is an urgent project for nuclear energy development. Herein, magnetic graphitic carbon nitride nanosheets were successfully prepared by in situ anchoring of pyrrhotite (Fe7S8) on the graphitic carbon nitride nanosheet (CNNS), which were used for capturing U-VI. The structural characterizations of Fe7S8/CNNS-1 indicated that the CNNS could prevent the aggregation of Fe7S8 and the saturation magnetization was 4.69 emu g(-1), which meant that it was easy to separate the adsorbent from the solution. Adsorption experiments were performed to investigate the sorption properties. The results disclosed that the sorption data conformed to the Langmuir isotherm model with the maximum adsorption capacity of 572.78 mg g(-1) at 298 K. The results of X-ray photoelectron spectroscopy (XPS) demonstrated that the main adsorption mechanism are as follows: U-VI is adsorbed on the surface of Fe7S8/CNNS-1 through surface complexation initially, then it was reduced to insoluble U-IV. Thereby, this work provided an efficient and easy to handle sorbent material for extraction of U-VI.