3D structure aerogels constructed by reduced graphene oxide and hollow TiO2 spheres for efficient visible-light-driven photoreduction of U(vi) in air-equilibrated wastewater

Abstract

Photocatalysis-assisted transition of uranium from the soluble U(VI) to the insoluble U(IV) is an efficient strategy for eliminating uranium. Herein, a novel 3D structure composite aerogel (3D RGO@TiO₂) was applied to photoreduction of U(VI) under visible light. The introduction of RGO could expand the light absorption region and facilitate efficient charge separation of 3D RGO@TiO₂. Therefore, 3D RGO@TiO₂-3 (where the mass ratio of GO and H-TiO₂ was 1 : 1) achieved the greatest U(VI) reduction rate (0.03752 min⁻¹) that is almost five times higher than that of RGO. Meanwhile, the reaction between photogenerated electrons and superoxide radicals ˙O₂⁻ played the dominant role in reducing U(VI) to (UO₂)O₂·2H₂O in air-equilibrated wastewater. This study not only provides new insights into remediation of the radioactive environment but also proves the application prospect of the 3D RGO@TiO₂ in the photocatalytic field.