Regulated dual defects of ligand defects and lattice defects in UIO-66 for ultra-trace simultaneous detection and removal of heavy metal ions

Abstract

Exploring multifunctional absorbents for the concurrent detection and elimination of heavy metal ions (HMIs) presents a significant challenge. In this study, dual defective bimetallic metal–organic framework materials (D-D-UIO-66) are synthesized by the solvothermal method. The incorporation of an acid and Ce³⁺ simultaneously introduces ligand defects and lattice defects, which provides a massive defective synergistic effect to enhance the intrinsic properties of D-D-UIO-66. D-D-UIO-66 can simultaneously detect Pb(II), Cd(II), Hg(II), and Cu(II), exhibiting high sensitivities of 15.209, 10.092, 2.829, and 1.347 μA μM⁻¹, respectively. D-D-UIO-66 also demonstrate excellent stability and anti-interference capabilities, and it has been effectively applied in real water environments. On the other hand, D-D-UIO-66 can remove Pb(II) from the water environment and achieve a maximum adsorption of 667.04 mg g⁻¹. The mechanisms behind the electrochemical detection and adsorption activities of D-D-UIO-66 are explored, which reveal that the synergistic interplay between distinct defects enhances the electronic microstructure, consequently boosting both electrochemical detection and adsorption capabilities. This study presents a strategy for multifunctional adsorbents, advancing the understanding of defect engineering and its influence on the fundamental mechanisms of material behavior.