Study on photocatalytic performance of hexagonal SnS2/g-C3N4 nanosheets and its application to reduce U (VI) in sunlight

In the present work, the photocatalytic technology is applied to remove hexavalent uranium(U(VI)) to purify the uranium-containing wastewater which discharged from the nuclear industry. To improve the optical performance of g-C3N4 nanosheets (g-CNNs), two-dimensional (2D) hexagonal SnS2 nanosheets were introduced, and the hererostructured catalysts show excellent removal performance for U(VI). It is worth noting that in the actual photocatalytic experiment under sunlight, the removal rate of U(VI) by 0.08-SnCN reached 90% at 2 h, indicating its high-efficiency catalytic performance and energy-saving potential. Subsequently, the introduction of organic matter simulates the actual uranium-bearing wastewater environment. Meanwhile, a series of characterization methods such as XRD, FT-IR, SEM, TEM, and UV–vis DRS were used to investigate the structure, morphology, and photoelectric properties of the photocatalysts. Furthermore, TEM, XPS, XRD and ESR were used to explore the catalytic mechanism. The results indicated that U(VI) was reduced by superoxide radical (⋅O2–) while competing electrons on the material surface, and deposited on the interface between SnS2 and g-CNNs in the form of (UO2)O2·H2O.