Fabrication of the novel Ag-doped SnS2@InVO4 composite with high adsorption-photocatalysis for the removal of uranium (VI)

作者：He, Shan; Yang, Zhiquan^*; Cui, Xiandi; Zhang, Xinyi; Niu, Xiaojun

来源：Chemosphere, 2020, 260: 127548.

DOI：10.1016/j.chemosphere.2020.127548

• Ag-doped SnS2@InVO4
• Visible light
• Adsorption-photocatalysis
• Uranium (VI) reduction

A novel Ag-doped SnS2@InVO4 composite was successfully synthesized for efficient uranium removal from wastewater through a facile hydrothermal method. The structure, morphology and optical property of materials were characterized using various instruments. The results proved that Ag-doped SnS2@InVO4 composite presented as hexangular nanosheets with about 4.87 nm pore size and 101.58 m(2)/g specific surface area. Further characterization demonstrated that photo-adsorption ability of visible light was enhanced and band gap was narrowed. The adsorption kinetics and isotherm of U(VI) on Ag-doped SnS2@InVO4 composite could be depicted via the Langmuir model and pseudo-second-order mode, and the maximum adsorption capacity of U(VI) reached 167.79 mg/g. The elimination of U(VI) of as-synthesized composites was studied by a synergy of adsorption and visible-light photocatalysis, and the optimal content of InVO4 was found to be 2 wt% with the highest removal efficiency of 97.6%. In addition, compared with pure SnS2 and Ag-doped SnS2, the Ag-doped SnS2@InVO4 composites exhibited superior photocatalytic performance for the conversion of soluble U(VI) to insoluble U(IV) under visible light. The excellent photocatalytic performance was mainly attributed to numerous surface-active sites, strong optical adsorption ability and narrow band gap. Simultaneously, the heterojunction between Agdoped SnS2 and InVO4 promoted the separation and transfer of photoexcited charges. The cyclic experiments indicated the Ag-doped SnS2@InVO4 composite remained good structural stability and reusability. Finally, the possible mechanism was discussed based on the experimental analysis.