Robust 2D porphyrin metal-organic framework nanosheets for high-efficiency photoreduction-assisted uranium recovery from wastewater

The elimination of highly radioactive and chemically toxic uranium from nuclear waste is of significance for radionuclide remediation and environment protection. Herein, two-dimensional (2D) porphyrin-based nickel (Ni-TCPP) metal-organic frameworks (MOFs) are successfully prepared by a simple surfactant-assisted strategy. Owing to highly accessible active sites and low diffusion barrier, 2D Ni-TCPP nanosheets present fast uranium capture by coordination of uranyl ions with TCPP ligands and Ni paddlewheel metal nodes. Particularly, 2D Ni-TCPP nanosheets display outstanding photocatalytic activity due to the merit of dual ligand-to-metal charge transfer pathways, greatly improving photoreduction-assisted uranium recovery performance. As a result, light-irradiated 2D Ni-TCPP adsorbents display fast removal of uranium from acidic wastewater, excellent selectivity and good reusability. Moreover, a high uranium removal rate can be maintained even in the presence of excess calcium ions. These advantages combined with good structure stability make 2D Ni-TCPP MOFs promising for selective uranium separation in nuclear waste remediation.