Solar light-responsive CdS/UiO-66-NH2 for ultrafast uranium reduction from uranium-containing mine wastewater without external sacrificial agents

Abstract

• 40 CUN achieved a record kinetic reaction rate reduction efficiency in air atmosphere and absence of sacrificial agents; • Cd 2+ ions are absorbed on UiO-66-NH 2 by the coordination bonds of Cd-N. • The photogenerated holes are consumed by oxidizing S 2− to SO 4 2− . • 85.62% of U(VI) in the uranium contained real mine wastewater could be removed under solar. As the nuclear industry ushered in a historical opportunity for rapid development, the massive discharge of nuclear waste liquids posed health risks to humans and environmental pollutant due to its combined chemotoxicity and radiotoxicity. Therefore, how to effectively treat uranium-containing mine wastewater is full of challenges. In this work, the CdS/UiO-66-NH 2 nanoparticles photocatalysts were prepared and applied for reduction of uranium hexavalent in the absence of any sacrificial agents. The kinetic photoreaction rate reaches 3.78 mmol/(g·h), which is a record among the reported rate. Excitingly, 85.62% of U(VI) in the mine wastewater could be removed under sunlight irradiation in the air condition. The results show that the photogenerated electrons rapidly transport from CdS to UiO-66-NH 2 due to the formation of heterojunction structure, whereas the photo-generated holes are consumed by oxidizing S 2− to SO 4 2− . This work represents an important step towards the remediation of the radioactive environment from mine wastewater, and promotes the extensive application of photocatalysis technology.