Coupling of CdS and g-C3N4 decorated dendritic fibrous nano-silica for efficient photocatalytic reduction of uranium (VI)

Uranium (VI) removal and recovery from wastewater is crucial for sustainable development of nuclear energy and environmental remediation. Among various techniques, the photocatalytic reducing uranium (VI) to immobile uranium (IV) has been regarded as one of the most effective strategies. As a result, the design and fabrication of photocatalysts have attracted extensive attention. In this study, g-C3N4 decorated dendritic fibrous nano-silica was fabricated first and then coupled with CdS. The fibrous photocatalyst showed high surface area and extended visible light absorption. More importantly, it exhibited a satisfying performance for the photocatalytic reduction of uranium (VI) under air atmosphere with solar irradiation. The SEM images and XPS spectrum confirmed that uranium (VI) was indeed photo-reduced to uranium (IV). Meanwhile, quenching experiments showed that O2− played a key role in uranium (VI) reduction.