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

[Display omitted] •A new green method for uranium removal via photocatalytic produced H2O2.•Uranium can be recovered without sacrificial agent under air.•Uranium can be removed from basic solution under solar energy.•Removal rate from simulated uranium-containing basic effluent reaches to 95.5%. 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 metastudtite 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.