| 内容提要: |
The metal sulfides are promising materials for their superior performance in the capture of radioactive nuclides from wastewater. Herein, Na/Zn/Sn/S (NaZTS) quaternary metal sulfide nanosheets were fabricated by a hydrothermal method. A series of characterizations reveal that the NaZTS nanosheets had the identical structure to Na5Zn3.5Sn3.5S13·6H2O, consisting of [Zn3.5Sn3.5S13]5– frameworks and Na+ ions located at the center and corner of the open channels. The S2– ligands on the structure endowed NaZTS with soft Lewis basic nature, which showed high affinity toward Sr2+ ions. NaZTS was employed to remove Sr2+ from aqueous solutions, and exhibited the ultrafast kinetics (equilibrium time of 5 min), broad active pH range (removal rate > 98.4% in the pH range of 3–12), and non-desorption feature (Sr2+ desorption rate < 0.04%). Meanwhile, the maximum adsorption capacity from Langmuir model was 40.4 mg g–1 at 318 K. The effects of adsorbent dosage and co-existing ions on Sr2+ adsorption were also discussed. X-ray photoelectron spectroscopy characterizations were used to study the adsorption mechanism, and the ion exchange and strong Sr···S bonding could be employed to explain the ability of NaZTS to capture Sr2+ ions. This work highlights the excellent adsorption performance of Sr2+ by NaZTS, thereby giving it a promising future for application in removal of radioactive Sr2+ in radioactive pollution cleanup. |