Photocatalytic uranium removal from basic effluent by porphyrin-Ni COF as the photocatalyst

Photocatalytic uranium removal from radioactive wastewater is considered as a green method to prevent environment contamination. However, almost all photocatalysts are used in anaerobic condition or with extra sacrificial agent. Herein, we report a strategy for non-sacrificial photocatalytic uranium removal from basic solution under air by photocatalyst TT-Por COF-Ni, which was synthesized via Aldamine reaction between 5,10,15,20-(tetra-4-aminophenyl)porphyrin-Ni (TPP-Ni) and thieno[3,2-b]thiophene-2,5-dicarbaldehyde (TT). Hydrogen peroxide (H2O2) is generated by photocatalytic reduction of O2, and followed by formation of met-astudtite via in situ reaction with uranyl. As a result, uranium can be photo-driven removed to 1 ppm residual in basic solution under air atmosphere without adding extra sacrificial agent, and uranium removal reached to 97.1 % upon solar illumination. Remarkably, our strategy can recover uranium with 95.5 % removal rate from simulated uranium-containing effluent from nuclear fuel cycle in basic condition, which suggests a potential for practical application.